WO2014069527A1

WO2014069527A1 - Hybrid vehicle regenerative brake control device

Info

Publication number: WO2014069527A1
Application number: PCT/JP2013/079420
Authority: WO
Inventors: 守洋長嶺; 久保　賢吾; 陽子吉岡; 加藤　芳章
Original assignee: 日産自動車株式会社; ジヤトコ株式会社
Priority date: 2012-11-01
Filing date: 2013-10-30
Publication date: 2014-05-08

Abstract

When an accelerator pedal is released (S11) and a brake pedal is depressed (S12), hybrid travel regeneration (S13) is started. When a time (ΔT) of the hybrid travel regeneration (with the brake pedal being depressed) reaches a predetermined time (ΔTs) at which both regeneration efficiency and starter motor protection are achieved, the clutch is disengaged so as to transition to electric travel regeneration (S15, S16, S18), while a dragging deceleration component (Gd) of an engine and a continuously variable transmission is added to regenerative braking force.

Description

Regenerative braking control device for hybrid vehicle

The present invention is equipped with an engine and an electric motor as a power source, and regenerative braking of a hybrid vehicle capable of selecting an electric travel mode (EV mode) using only the electric motor and a hybrid travel mode (HEV mode) using the electric motor and engine. The present invention relates to a control device.

As such a hybrid vehicle, a vehicle as described in Patent Document 1, for example, is conventionally known.
This hybrid vehicle is of a type in which an engine, which is one power source, is detachably connected to a wheel by a clutch, and an electric motor, which is the other power source, is always coupled to the wheel.

Such a hybrid vehicle is capable of electric travel (EV travel) in the EV mode only by an electric motor by stopping the engine and releasing the clutch, and by starting the engine and engaging the clutch. Hybrid running (HEV running) in HEV mode with an electric motor and engine is possible.

By releasing the clutch as described above during EV travel, the engine (and transmission if a transmission is present) is disconnected from the wheel, and the engine (transmission) is disconnected during EV travel. It is not accompanied (pulled), and energy loss can be avoided and energy efficiency can be increased.

JP 2000-199442 A

In the hybrid vehicle described above, when the accelerator pedal is released during HEV traveling and the vehicle shifts to coasting (inertia) traveling, or when the vehicle is braked by depressing the brake pedal thereafter, the vehicle is regenerated by an electric motor. The energy efficiency is also improved by converting the kinetic energy into electric power and storing it in the battery.

By the way, during regenerative braking (HEV regeneration), the engine (transmission) is separated from the wheels by releasing the clutch as soon as possible (simultaneously with the start of regenerative braking). In order to increase energy efficiency, it is important to make it possible to earn the amount of energy regeneration by eliminating the rotation of).

On the other hand, at the time of releasing the clutch, from the viewpoint of fuel consumption, the engine should be stopped so that unnecessary operation is not performed. Therefore, the fuel to the engine that was being executed during the coasting (inertia) traveling In order to stop injection (fuel cut) even when the clutch is released, it is customary to prohibit the restart of fuel injection (fuel recovery) to the engine and stop the engine when the clutch is released.

However, when the engine is stopped in this way, it is necessary to restart the engine with the starter motor due to insufficient driving force at the time of reacceleration when the accelerator pedal is depressed, and to switch from the EV mode to the HEV mode by engaging the clutch. .

Therefore, in order to increase the energy regeneration efficiency, if the clutch is released immediately at the start of regenerative braking to disconnect the engine from the wheel and stop the engine,
If you are driving by a driver who is willing to release or re-press the accelerator pedal, or if you are using the vehicle in a driving environment where you are primarily forced to do so, you must Since the restart is frequently performed, the number of start times of the starter motor for starting the engine reaches the number of start times of durability at an early stage, which is very disadvantageous from the viewpoint of protecting the starter motor.

The hybrid vehicle described in Patent Document 1 does not make any technical proposals regarding the clutch release timing for switching from HEV regeneration to EV regeneration,
In order to increase the energy regeneration efficiency using conventional means, it is appropriate to immediately release the clutch at the start of regenerative braking, disconnect the engine from the wheels, and switch from HEV regeneration to EV regeneration.

However, as usual, if the engine is disconnected from the wheel by releasing the clutch immediately at the start of regenerative braking with the highest priority on energy regeneration efficiency,
The engine restarts frequently during driving by a driver with a high accelerator change frequency or in a driving environment where the accelerator change frequency is high, and the starter motor start count reaches the endurance start count at an early stage. Cause problems with durability.

However, giving priority to the protection of the starter motor (improvement of durability) and releasing the clutch after a significant delay from the start of regenerative braking will increase the HEV regeneration period that rotates the engine (transmission). There arises a problem that the energy regeneration efficiency is deteriorated by the amount of rotation energy of the (transmission).

In the present invention, from the viewpoint that the demand for improving the energy regeneration efficiency and the protection demand for the starter motor are in a trade-off relationship, the release of the clutch is performed at a timing when both demands are compatible under a high-dimensional balance. An object of the present invention is to propose a regenerative braking control device for a hybrid vehicle configured to be performed.

For this purpose, the regenerative braking control device for a hybrid vehicle according to the present invention is configured as follows.
First, to explain the hybrid vehicle which is the premise of the present invention,
The engine is detachably drive-coupled to the wheels via a clutch, and by releasing the clutch, electric traveling only by the electric motor is possible, and by hybridizing the electric motor and the engine by engaging the clutch It is a possible hybrid vehicle.

The present invention is characterized by a configuration in which the following clutch release permission means is provided for such a hybrid vehicle.
The clutch release permission means permits the release of the clutch after a predetermined period from the start of the regenerative braking when performing regenerative braking by the electric motor in the hybrid travel state.

The regenerative braking control device for a hybrid vehicle according to the present invention, when performing regenerative braking in a hybrid running state, permits the release of the clutch after a predetermined period from the start of the regenerative braking.
The clutch is not immediately released (engine disengagement) at the start of regenerative braking, and the engine restarts even during driving by a driver with a high accelerator change frequency or in an operating environment where the accelerator change frequency increases. As a result, it is possible to solve the above-mentioned problem related to the durability of the starter motor, in which the starter motor reaches the endurance start number earlier.

Further, since the release of the clutch is permitted after the period has elapsed, the deterioration of the energy regeneration efficiency until the release of the clutch is permitted is limited.
Therefore, the regenerative braking control device for a hybrid vehicle according to the present invention can balance the requirements related to the protection of the starter motor and the requirements related to the energy regenerative efficiency in a highly balanced manner, either of which is greatly sacrificed. Can be solved.

1 is a schematic system diagram showing an overall control system related to a drive system of a hybrid vehicle including a regenerative braking control device according to a first embodiment of the present invention. 1 shows another type of hybrid vehicle to which the regenerative braking control device of the present invention can be applied, wherein (a) is a schematic system diagram showing an overall control system related to the drive system of the hybrid vehicle, and (b) is the hybrid vehicle. FIG. 6 is an engagement logic diagram of a shift friction element of a sub-transmission built in a V-belt type continuously variable transmission in the drive system of FIG. 3 is a flowchart showing a regenerative braking control program executed by the hybrid controller in FIG. FIG. 4 is a characteristic diagram showing a relationship between a clutch release delay time from the start of HEV regeneration used in the regenerative braking control of FIG. 3, engine start frequency, and regenerative energy. 4 is an operation time chart of a regenerative braking control program according to the first embodiment shown in FIG. FIG. 4 is a flowchart similar to FIG. 3, showing a regenerative braking control program of a regenerative braking control device according to a second embodiment of the present invention. 7 is an operation time chart of the regenerative braking control program according to the second embodiment shown in FIG. FIG. 6 is a flowchart similar to FIG. 3, showing a regenerative braking control program of a regenerative braking control device according to a third embodiment of the present invention. FIG. 9 is an operation time chart of the regenerative braking control program according to the third embodiment shown in FIG.

1 Engine (power source)
2 Electric motor (power source)
3 Starter motor 4 V belt type continuously variable transmission 5 Drive wheel 6 Primary pulley 7 Secondary pulley 8 V belt CVT Continuously variable transmission mechanism T / C Torque converter CL Clutch 9,11 Final gear set 12 Battery 13 Inverter 14 Brake disk 15 Caliper 16 Brake pedal 17 Negative pressure brake booster 18 Master cylinder 19 Accelerator pedal 21 Hybrid controller 22 Engine controller 23 Motor controller 24 Transmission controller 25 Battery controller 26 Brake switch 27 Accelerator opening sensor O / P Oil pump 31 Sub-transmission H / C High clutch R / B Reverse brake L / B Low brake 32 Vehicle speed sensor 33 Vehicle acceleration sensor 35 Line pressure solenoid 36 Lockup solenoid 37 Primary pulley pressure solenoid 38 Low brake pressure solenoid 39 High clutch And reverse brake pressure solenoid 41 switch valve

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<Configuration>
FIG. 1 is a schematic system diagram showing an overall control system related to a drive system of a hybrid vehicle including a regenerative braking control device according to a first embodiment of the present invention.

The hybrid vehicle is mounted with the engine 1 and the electric motor 2 as power sources, and the engine 1 is started by the starter motor 3.
The engine 1 is drive-coupled to the driving wheel 5 through a V-belt type continuously variable transmission 4 so as to be appropriately separable, and the V-belt type continuously variable transmission 4 is as outlined below.

The V-belt type continuously variable transmission 4 includes a continuously variable transmission mechanism CVT including a primary pulley 6, a secondary pulley 7, and a V belt 8 spanned between the

pulleys

6 and 7 as main components.
The primary pulley 6 is coupled to the crankshaft of the engine 1 via the torque converter T / C, and the secondary pulley 7 is coupled to the drive wheel 5 via the clutch CL and the final gear set 9 in order.

Thus, with the clutch CL engaged, the power from the engine 1 is input to the primary pulley 6 via the torque converter T / C, and then sequentially passes through the V belt 8, the secondary pulley 7, the clutch CL and the final gear set 9 to drive wheels 5 To be used for running the hybrid vehicle.

During the transmission of the engine power, the pulley V groove width of the secondary pulley 7 is increased while the pulley V groove width of the primary pulley 6 is reduced, so that the V-belt 8 wraps around the primary pulley 6 with a larger arc diameter. At the same time, the winding arc diameter with the secondary pulley 7 is reduced, and the V-belt continuously variable transmission 4 performs an upshift to a high pulley ratio.
Conversely, by increasing the pulley V groove width of the primary pulley 6 and decreasing the pulley V groove width of the secondary pulley 7, the V belt 8 is wound around the primary pulley 6 and the arc diameter of the secondary pulley 6 is reduced at the same time. The winding arc diameter with 7 is increased, and the V-belt type continuously variable transmission 4 performs a downshift to a low pulley ratio.

The electric motor 2 is always coupled to the drive wheel 5 via the final gear set 11, and the electric motor 2 is driven via the inverter 13 by the power of the battery 12.
The inverter 13 converts the DC power of the battery 12 into AC power and supplies it to the electric motor 2 and adjusts the power supplied to the electric motor 2 to control the driving force and the rotational direction of the electric motor 2.

The electric motor 2 functions as a generator in addition to the motor drive described above, and is also used for regenerative braking described in detail later.
During this regenerative braking, the inverter 13 applies a power generation load corresponding to the regenerative braking force to the electric motor 2 to act as a generator, and the generated power of the electric motor 2 is stored in the battery 12.

In a hybrid vehicle having the drive system described above with reference to FIG. 1, when the electric motor 2 is driven with the clutch CL released and the engine 1 stopped, only the power of the electric motor 2 is driven through the final gear set 11. The vehicle reaches the wheel 5 and the hybrid vehicle can perform electric traveling (EV traveling) using only the electric motor 2.
During this time, by disengaging the clutch CL, it is possible to suppress power consumption during EV traveling without causing the stopped engine 1 to rotate.

When the engine 1 is started by the starter motor 3 and the clutch CL is engaged in the EV running state, the power from the engine 1 is converted to the torque converter T / C, the primary pulley 6, the V belt 8, the secondary pulley 7, the clutch CL, The final gear set 9 is sequentially passed to reach the drive wheel 5, and the vehicle can perform hybrid travel (HEV travel) using the engine 1 and the electric motor 2.

When the hybrid vehicle is stopped from the above running state or kept in this stopped state, the brake disk 14 that rotates together with the drive wheel 5 is clamped by the caliper 15 to be braked.
The caliper 15 is connected to a master cylinder 18 that responds to the depressing force of the brake pedal 16 that the driver depresses and outputs a brake hydraulic pressure corresponding to the brake pedal depressing force under the boost of the negative pressure type brake booster 17. The caliper 15 is operated to brake the brake disc 14.

In both the EV mode and the HEV mode, the hybrid vehicle is driven with the driving force command according to the driver's request by driving the wheel 5 with the torque according to the driving force command that the driver depresses the accelerator pedal 19. The

Hybrid vehicle travel mode selection, engine 1 output control, electric motor 2 rotational direction control and output control, continuously variable transmission 4 shift control and clutch CL engagement / release control, and battery 12 charge / discharge Control is performed by the hybrid controller 21 via the corresponding engine controller 22, motor controller 23, transmission controller 24, and battery controller 25, respectively.

Therefore, the hybrid controller 21 includes an accelerator opening sensor 27 that detects a signal from a brake switch 26 that is a normally open switch that switches from OFF to ON during braking when the brake pedal 16 is depressed, and an accelerator pedal depression amount (accelerator opening) APO. The signal from is input.
The hybrid controller 21 further exchanges internal information with the engine controller 22, the motor controller 23, the transmission controller 24, and the battery controller 25.

The engine controller 22 controls the output of the engine 1 in response to a command from the hybrid controller 21.
The motor controller 23 performs rotation direction control and output control of the electric motor 2 via the inverter 13 in response to a command from the hybrid controller 21.

The transmission controller 24 responds to a command from the hybrid controller 21 and controls the transmission of the continuously variable transmission 4 (V-belt continuously variable transmission mechanism CVT) using oil from the oil pump O / P driven by the engine as a medium. In addition, the clutch CL is engaged and released.
The battery controller 25 performs charge / discharge control of the battery 12 in response to a command from the hybrid controller 21.

In FIG. 1, the V-belt type continuously variable transmission mechanism CVT (secondary pulley 7) and the driving wheel 5 are detachably connected to each other, so that the continuously variable transmission 4 has a dedicated clutch CL.
As illustrated in FIG. 2 (a), when the continuously variable transmission 4 includes the auxiliary transmission 31 between the V-belt type continuously variable transmission mechanism CVT (secondary pulley 7) and the drive wheel 5, The friction element (clutch, brake, etc.) that controls the speed change of the transmission 31 can be used to detachably connect the V-belt type continuously variable transmission mechanism CVT (secondary pulley 7) and the drive wheel 5. .
In this case, there is no need to additionally install a dedicated clutch for detachably connecting the V-belt type continuously variable transmission mechanism CVT (secondary pulley 7) and the drive wheel 5, which is advantageous in terms of cost.

The sub-transmission 31 in FIG. 2 (a) includes composite sun gears 31s-1 and 31s-2, an inner pinion 31pin, an outer pinion 31pout, a ring gear 31r, and a carrier 31c that rotatably supports the pinions 31pin and 31pout. It consists of a Ravigneaux type planetary gear set consisting of
Of the composite sun gears 31s-1 and 31s-2, the sun gear 31s-1 is coupled to the secondary pulley 7 so as to act as an input rotating member, and the sun gear 31s-2 is arranged coaxially with respect to the secondary pulley 7, but freely rotates. To get.

The inner pinion 31pin is engaged with the sun gear 31s-1, and the inner pinion 31pin and the sun gear 31s-2 are respectively engaged with the outer pinion 31pout.
The outer pinion 31pout meshes with the inner periphery of the ring gear 31r, and is coupled to the final gear set 9 so that the carrier 31c acts as an output rotating member.

The carrier 31c and the ring gear 31r can be appropriately connected by the high clutch H / C, the ring gear 31r can be appropriately fixed by the reverse brake R / B, and the sun gear 31s-2 can be appropriately fixed by the low brake L / B. .

The sub-transmission 31 fastens the high clutch H / C, reverse brake R / B, and low brake L / B, which are shift friction elements, in a combination indicated by a circle in FIG. The first forward speed, the second speed, and the reverse gear position can be selected by releasing as shown by x in (b).

When the high clutch H / C, reverse brake R / B, and low brake L / B are all released, the sub-transmission 31 is in a neutral state where no power is transmitted,
When the low brake L / B is engaged in this state, the auxiliary transmission 31 enters the first forward speed selection (deceleration) state,
When the high clutch H / C is engaged, the auxiliary transmission 31 enters the second forward speed selection (direct connection) state,
When the reverse brake R / B is engaged, the auxiliary transmission 31 is in the reverse selection (reverse) state.

The continuously variable transmission 4 shown in FIG. 2 releases the variable speed friction elements H / C, R / B, L / B and makes the sub-transmission 31 neutral. The (secondary pulley 7) and the drive wheel 5 can be disconnected.
Therefore, in the continuously variable transmission 4 of FIG. 2, the shift friction elements H / C, R / B, L / B of the sub-transmission 31 correspond to the clutch CL in FIG. 1, and the clutch CL is additionally provided as in FIG. Therefore, the V-belt continuously variable transmission mechanism CVT (secondary pulley 7) and the drive wheel 5 are detachably coupled.

The continuously variable transmission 4 in FIG. 2 uses oil from an oil pump O / P driven by the engine as a working medium, and the transmission controller 24 includes a line pressure solenoid 35, a lockup solenoid 36, a primary pulley pressure solenoid 37, and a low brake. Control is performed as follows through the pressure solenoid 38, the high clutch pressure & reverse brake pressure solenoid 39, and the switch valve 41.

In addition to the signal described above with reference to FIG. 1, a signal from the vehicle speed sensor 32 that detects the vehicle speed VSP and a signal from the acceleration sensor 33 that detects the vehicle acceleration / deceleration G are input to the transmission controller 24.

In response to a command from the transmission controller 24, the line pressure solenoid 35 regulates the oil from the oil pump O / P to the line pressure P _L corresponding to the vehicle required driving force, and this line pressure P _L is always the secondary pulley 7 By supplying the secondary pulley pressure to the secondary pulley 7, the secondary pulley 7 clamps the V-belt 8 with a thrust according to the line pressure P _L.

The lockup solenoid 36 responds to a lockup command from the transmission controller 24 and directs the torque converter T / C directly between the input / output elements by appropriately directing the line pressure P _L to the torque converter T / C. Set the lockup state.

The primary pulley pressure solenoid 37 adjusts the line pressure P _L to the primary pulley pressure in response to the CVT gear ratio command from the transmission controller 24, and supplies the pressure to the primary pulley 6, thereby supplying the V groove of the primary pulley 6. The CVT gear ratio command from the transmission controller 24 is controlled by controlling the width and the V groove width of the secondary pulley 7 to which the line pressure P _L is supplied so that the CVT gear ratio matches the command from the transmission controller 24. To realize.

The low brake pressure solenoid 38 is engaged by supplying the line pressure P _L to the low brake L / B as the low brake pressure when the transmission controller 24 issues the first speed selection command for the sub-transmission 31. To achieve the first speed selection command.

High clutch pressure & reverse brake pressure solenoid 39 switches line pressure P _L as high clutch pressure & reverse brake pressure when transmission controller 24 issues second speed selection command or reverse selection command for sub-transmission 31 Supply to valve 41.
At the time of the second speed selection command, the switch valve 41 uses the line pressure P _L from the solenoid 39 as the high clutch pressure to the high clutch H / C, and by engaging this, the second speed selection command of the auxiliary transmission 31 is established. To realize.
During retraction selection command switch valve 41, the line pressure P _L from the solenoid 39 directs the reverse brake R / B as the reverse brake pressure, to achieve a backward selection command of auxiliary transmission 31 by engaging it.

<Regenerative braking control>
The regenerative braking control of the hybrid vehicle will be described below when the vehicle drive system is as shown in FIG.
When the accelerator pedal 19 is released during HEV driving and the vehicle shifts to coasting (inertia) driving, or when the vehicle is braked by stepping on the brake pedal 16, the kinetic energy of the vehicle is converted into electric power by regenerative braking by the electric motor 2. By converting and storing this in the battery 12, energy efficiency is improved.

By the way, in the regenerative braking (HEV regeneration) with HEV running, the clutch CL is in the engaged state, so the regenerative braking energy is reduced by the reverse drive force (engine brake) of the engine 1 and the friction of the continuously variable transmission 4. The energy regeneration efficiency is poor.
Therefore, if regenerative braking is started during HEV traveling, EV regeneration is achieved by separating engine 1 and continuously variable transmission 4 from drive wheels 5 by releasing clutch CL simultaneously with the start of HEV regeneration and shifting to EV traveling. In order to increase the energy efficiency, it is important to increase the amount of energy regeneration by eliminating the rotation of the engine 1 and the continuously variable transmission 4.

On the other hand, when the clutch CL is released as described above, the engine 1 is stopped during coasting (inertia) in order to stop the engine 1 from performing unnecessary driving from the viewpoint of fuel efficiency. In order to stop the fuel injection to the engine 1 (fuel cut) even when the clutch CL is released, the restart of the fuel injection to the engine 1 (fuel recovery) is prohibited and the engine 1 is stopped when the clutch CL is released. Let

However, when the engine 1 is stopped in this way, the required driving force cannot be covered only by the electric motor 2 at the time of reacceleration when the accelerator pedal 19 is depressed, and the engine 1 becomes the starter motor 3 The engine is restarted and the clutch CL is engaged to switch from EV traveling to HEV traveling.

Therefore, in order to increase the energy regeneration efficiency, the clutch is immediately released at the start of HEV regeneration, and the engine 1 and the continuously variable transmission 4 are disconnected from the drive wheel 5 and the engine 1 is stopped.
If you are driving by a driver who is willing to release the accelerator pedal 19 or depressing it frequently, or if you are using the vehicle in a driving environment where you are primarily forced to do so, you must use the engine. This is disadvantageous from the viewpoint of protection of the starter motor, since the number of restarts of the starter motor 3 for engine start reaches the endurance start number early.

However, if the priority is given to protection of the starter motor 5 (improvement of durability) and the clutch CL is released largely after the start of HEV regenerative braking, the HEV regeneration period in which the engine 1 and the continuously variable transmission 4 are rotated together. As a result, the problem arises that the energy regeneration efficiency deteriorates by the amount of entrained energy of the engine 1 and the continuously variable transmission 4.

Therefore, in this embodiment, the drive system shown in FIG. 1 is provided so that the demand for improving the energy regeneration efficiency and the protection demand for the starter motor 3 which are in a trade-off relationship as described above can be balanced at a high level. Regenerative braking control of hybrid vehicles is performed as follows.

For this purpose, the hybrid controller 21 of FIG. 1 starts the regenerative braking control program of FIG. 3 during HEV traveling.
In addition, the control program of FIG. 3 shows that when the permit condition for regenerative braking by the electric motor 2 is satisfied, for example, the temperature of the electric motor 2 is in a temperature range that is safe even if power generation is performed, and the temperature of the battery 12 Needless to say, the operation is performed when the temperature is within a possible temperature range and the battery 12 is in a storage state where the remaining charge capacity remains.

In step S11, it is checked whether or not the coasting (inertia) traveling is performed from the accelerator opening APO, and in step S12, the brake switch 26 is turned on (the brake pedal 16 is depressed). Check whether it is in the braking state).
This embodiment is based on the assumption that when the accelerator pedal 19 is released and the brake pedal 16 is depressed, regenerative braking is performed.
If it is determined in step S11 that the accelerator pedal 19 is not released or it is determined in step S12 that the brake switch 26 is not ON (non-braking state), the control is terminated as it is and the control program of FIG. 3 is exited.

Incidentally, during coasting where the accelerator pedal 19 is released, fuel supply to the engine 1 is interrupted (fuel cut) to improve fuel efficiency as usual.

When it is determined in step S11 that the accelerator pedal 19 is released and the brake switch 26 is determined to be ON (braking state) in step S12, the control proceeds to step S13 because the regenerative braking conditions are met, Regenerative braking (HEV regeneration) is performed so that a predetermined deceleration according to the driving state is obtained under HEV traveling.

In the next step S14, it is determined whether or not the brake switch ON (braking) determination in step S12 has continued for a predetermined time ΔTs or more, that is, whether or not the brake switch ON time ΔT (HEV regeneration time) is a predetermined time ΔTs or more. A check is made to determine whether or not a predetermined period has elapsed since the start of regenerative braking.

Here, the predetermined time ΔTs related to the brake switch ON time ΔT (HEV regeneration time) will be described.
FIG. 4 shows the regenerative energy (fuel consumption) obtained for each clutch release delay time ΔT from the start of HEV regeneration to the start of EV regeneration by releasing the clutch CL, and the engine restart frequency described above (starter motor 3 start-up frequency). Are shown together with the target achievement range of the regenerative energy (fuel consumption) and the number of start-ups of the starter motor 3 (the limit number of start-ups in the starter motor protection establishment range).

The data shown in FIG. 4 can be obtained in advance by experiments and the like. In the GOOD region, the target of regenerative energy (fuel consumption) can be achieved, and the starter motor 3 is started less than the protection establishment limit start number, and the starter motor 3 protections can also be established.
However, in other NG areas, the target of regenerative energy (fuel consumption) cannot be achieved, or the starter motor 3 start count is more than the protection start limit start count and the starter motor 3 cannot be protected. As described above, it is impossible to satisfy both the demand for improving the energy regeneration efficiency and the protection demand for the starter motor, which are in a trade-off relationship.

In order to achieve this compatibility, the clutch release delay time ΔT from the start of HEV regeneration to the start of EV regeneration due to the release of the clutch CL is longer than the time in the GOOD region of FIG. 4, that is, ΔT1, and less than ΔT2. There must be.
Therefore, in this embodiment, the time ΔT1 in FIG. 4 is used as the predetermined time ΔTs related to the brake switch ON time ΔT (HEV regeneration time).

While it is determined in step S14 that the brake switch ON time ΔT (HEV regeneration time) is less than the predetermined time ΔTs, the control is returned to step S13, and the predetermined deceleration according to the driving state is obtained with the current HEV running. Continue HEV regeneration.
When it is determined in step S14 that the brake switch ON time ΔT (HEV regeneration time) is equal to or longer than the predetermined time ΔTs, the control proceeds to step S15 to permit the release of the clutch CL.
Therefore, step S14 and step S15 correspond to clutch release permission means in the present invention.

In the next step S16, resumption of fuel supply (fuel recovery) to the engine 1 that has been fuel cut as described above is prohibited and fuel cut is continued.
Therefore, step S16 corresponds to the fuel recovery prohibiting means in the present invention.

In step S17, drag deceleration Gd of engine 1 and continuously variable transmission 4 via clutch CL in the engaged state is calculated from CVT pulley ratio, engine speed Ne, and vehicle speed VSP.
Then, in step S18, the clutch CL is released under the condition that the HEV → EV mode switching condition is satisfied, and the engine 1 is stopped in combination with the prohibition of fuel recovery (continuation of fuel cut) in step S16, thereby shifting to EV driving. Switch from HEV regeneration to EV regeneration.

By the way, if the regenerative braking in step S13 is continued even after switching to the EV regenerative operation, the regenerative braking here is premised on HEV traveling in which the engine 1 and the continuously variable transmission 4 are dragged via the clutch CL in the engaged state. Due to the regenerative braking, the vehicle deceleration is insufficient with respect to the request by the drag deceleration of the engine 1 and the continuously variable transmission 4.
Therefore, in step S19, the drag deceleration Gd of the engine 1 and continuously variable transmission 4 obtained in step S17 is added to the regenerative braking force, and EV regeneration is performed so that the added regenerative braking force is obtained. Even after switching to regeneration, a predetermined deceleration according to the driving state is obtained under the current EV driving.

The regenerative braking in FIG. 3 will be described in detail below based on the time chart in FIG.
During HEV running with clutch CL engaged, release accelerator pedal 19 at instant t1 in FIG. 5 and shift to coasting (inertia) running with accelerator opening APO = 0 (step S11), supply fuel to engine 1 Stop (fuel cut) and set the fuel injection amount to 0 as shown in FIG.

When braking is performed by depressing the brake pedal 16 as indicated by the brake switch 26 = ON at the instant t2 (step S12), HEV regeneration is started because the regenerative braking conditions in this embodiment are met (step S13).
By this HEV regeneration, the electric motor 2 performs regenerative braking so as to obtain a predetermined deceleration according to the driving state during HEV traveling, so that power is generated as apparent from the generated power after the instant t2 in FIG. The vehicle speed VSP is gradually decreased and at the same time the battery charge state SOC is increased.

The HEV regeneration described above is continued until the instant t3 (step S14) when the brake switch ON time ΔT (HEV regeneration time) from the instant t2 reaches the predetermined time ΔTs.
From the instant t3 (step S14) when the brake switch ON time ΔT (HEV regeneration time) from the instant t2 reaches the predetermined time ΔTs to the instant t4, the clutch CL that has been engaged so far is released and the engine 1 Is stopped as indicated by the engine speed Ne = 0 by the fuel cut (fuel injection amount = 0) continued by prohibiting the fuel recovery in step S16 (step S16 and step S18).
This switches from HEV traveling to EV traveling, and EV regeneration is performed from instant t4.

In this EV regeneration, the regenerative braking force is added by the drag deceleration Gd of the engine 1 and the continuously variable transmission 4 during the HEV regeneration obtained in step S17.
As a result, the power generated by the EV regeneration is increased by the drag deceleration Gd as seen after the instant t4 in FIG.
In this way, by adding the regenerative braking force in EV regeneration by the drag deceleration Gd of engine 1 and continuously variable transmission 4, the current EV running is maintained after switching to EV regeneration as in HEV regeneration. Regenerative braking that provides a predetermined deceleration according to the operating state can be performed.

<Effect>
According to the regenerative braking control of the first embodiment described above, when the brake switch ON time ΔT (HEV regenerative time) becomes equal to or longer than the predetermined time ΔTs (step S14), that is, after HEV regeneration continues for the predetermined time ΔTs. Therefore, it is determined that a predetermined period has elapsed since the start of regenerative braking, and the release of the clutch CL (switching from HEV regeneration to EV regeneration with the engine 1 stopped) is permitted (step S15).
Release of the clutch CL (switching from HEV regeneration to EV regeneration with engine 1 stop) is after the start of HEV regeneration (when the brake switch 26 is ON) and is necessary to protect the starter motor It is permitted at a predetermined timing as early as possible.

For this reason, the clutch CL is not released immediately after starting HEV regeneration (switching from HEV regeneration to EV regeneration with the engine 1 stopped), and the driver is changing the accelerator while the accelerator is changing frequently. It is possible to prevent frequent engine restarts even in an operating environment where the frequency is high, and as a result, the starter motor 3 has an endurance start count that reaches the endurance start count early. Therefore, the starter motor 3 can be protected.

Even if the release of the clutch CL is permitted after the start of HEV regeneration (when the brake switch 26 is ON) (switching from HEV regeneration to EV regeneration with the engine 1 stopped), the starter motor 3 In order to command the permission at the prescribed timing as early as necessary for protection,
The clutch CL release timing (HEV regeneration → EV regeneration switching) is only delayed by the minimum time necessary to solve the problem related to the durability of the starter motor 3 from the start of HEV regeneration. The degradation in efficiency is negligible and can almost be ignored.
Therefore, the regenerative braking control device for a hybrid vehicle according to the present embodiment can satisfy both the requirements related to protection of the starter motor 3 and the requirements related to energy regenerative efficiency in a highly balanced manner, and one of them is greatly sacrificed. Does not cause the problem of becoming.

In addition, in this embodiment, when the release of the clutch CL (switching from HEV regeneration to EV regeneration) is permitted, the fuel cut to the engine 1 performed in response to the release of the accelerator pedal is continued. Because the fuel recovery is prohibited (step S16)
The engine 1 is stopped when the clutch is released, and in addition to avoiding a control collision, the fuel efficiency of the engine 1 can be expected.

<Configuration>
FIG. 6 is a regenerative braking control program similar to FIG. 3, showing a regenerative braking control device for a hybrid vehicle according to a second embodiment of the present invention.
Like the first embodiment, this embodiment also relates to the regenerative braking control of the hybrid vehicle having the drive system shown in FIG. 1 or FIG. 2 (a), but the case where the drive system is as shown in FIG. Expand the description.
Accordingly, in this embodiment, regenerative braking is performed immediately after the shift to coasting (inertia) traveling to release the accelerator pedal 19, even if the braking operation by depressing the brake pedal 16 is not performed.

In step S21 in FIG. 6 started during HEV traveling, it is checked whether or not the coasting (inertia) traveling in which the accelerator pedal 19 is released from the accelerator opening APO.
Since this embodiment is based on the premise that regenerative braking is performed only by releasing the accelerator pedal 19 as described above, when it is determined in step S21 that the accelerator pedal 19 is not in the released state, the control is ended as it is. Exit from 6 control program.

When it is determined in step S21 that the coasting (inertia) traveling is performed with the accelerator pedal 19 released, the control proceeds to step S22 because the regenerative braking conditions are met, and the current driving condition is determined based on the current HEV traveling. Regenerative braking (HEV regeneration) is performed to obtain a predetermined deceleration.

In the next step S23, it is checked whether or not the brake switch 26 is ON (braking state in which the brake pedal 16 is depressed). If the brake switch 26 is not ON (braking state), the control is returned to step S22. Continue HEV regeneration.

If it is determined in step S23 that the brake switch 26 is ON (braking state), whether or not the brake switch ON (braking) determination in step S23 has continued for a predetermined time ΔTs in step S24, that is, during HEV regeneration. It is checked whether or not the brake switch ON time ΔT has become equal to or longer than the predetermined time ΔTs, and it is determined whether or not a predetermined period has elapsed since the start of regenerative braking.
Note that the predetermined time ΔTs is determined in the same manner as described above with reference to FIG. This is the delay time from the moment the brake switch is turned on (HEV regeneration → EV regeneration switching timing).

While it is determined in step S24 that the brake switch ON time ΔT during HEV regeneration is less than the predetermined time ΔTs, the control returns to step S22, and the predetermined deceleration according to the driving state is obtained with the current HEV running. Continue HEV regeneration.
When it is determined in step S24 that the brake switch ON time ΔT during HEV regeneration is equal to or longer than the predetermined time ΔTs, the control proceeds to step S25 to permit the release of the clutch CL.
Therefore, step S24 and step S25 correspond to clutch release permission means in the present invention.

In the next step S26, fuel supply restart (fuel recovery) to the engine 1 that has been fuel cut as described above is prohibited and fuel cut is continued.
Therefore, step S26 corresponds to the fuel recovery prohibiting means in the present invention.

In step S27, drag deceleration Gd of engine 1 and continuously variable transmission 4 via clutch CL in the engaged state is calculated from CVT pulley ratio, engine speed Ne, and vehicle speed VSP.
Then, in step S28, the clutch CL is released under the condition that the HEV → EV mode switching condition is satisfied, and the engine 1 is stopped in combination with prohibition of fuel recovery (continuation of fuel cut) in step S26, thereby shifting to EV driving. Switch from HEV regeneration to EV regeneration.

By the way, if the regenerative braking in step S22 is continued even after switching to the EV regenerative operation, the regenerative braking here is premised on HEV traveling that drags the engine 1 and the continuously variable transmission 4 through the clutch CL in the engaged state. Due to the regenerative braking, the vehicle deceleration is insufficient with respect to the request by the drag deceleration of the engine 1 and the continuously variable transmission 4.
Therefore, in step S29, the drag deceleration amount Gd of the engine 1 and continuously variable transmission 4 obtained in step S27 is added to the regenerative braking force, and EV regeneration is performed so that the added regenerative braking force is obtained. Even after switching to regeneration, a predetermined deceleration according to the driving state is obtained under the current EV driving.

The regenerative braking in FIG. 6 will be described in detail below based on the time chart in FIG.
During HEV running with clutch CL engaged, release accelerator pedal 19 at instant t1 in FIG. 7 and shift to coasting (inertia) running with accelerator opening APO = 0 (step S21), supply of fuel to engine 1 Stop (fuel cut) and set the fuel injection amount to 0 as shown in FIG.

In this embodiment, since only the release of the accelerator pedal 19 is used as a regenerative braking condition, HEV regeneration is started at the accelerator pedal release instant t1 (step S22).
With this HEV regeneration, the electric motor 2 performs regenerative braking so as to obtain a predetermined deceleration according to the driving state during HEV traveling so that the power is generated clearly from the generated power after the instant t1 in FIG. The vehicle speed VSP is gradually decreased and at the same time the battery charge state SOC is increased.

When braking is performed by depressing the brake pedal 16 as indicated by the brake switch 26 = ON at the instant t2 (step S23), the required deceleration by this braking operation should be realized by cooperation between regenerative braking and friction braking by the brake unit. The regenerative braking force due to HEV regeneration is increased, and the generated power increases stepwise as at the instant t2 in FIG.

The HEV regeneration described above is continued until the instant t3 (step S24) when the brake switch ON time ΔT from the instant t2 reaches the predetermined time ΔTs.
While the brake switch ON time ΔT (HEV regeneration time) from the instant t2 reaches the predetermined time ΔTs, from the instant t3 (step S24) to the instant t4, the clutch CL that has been engaged is released and the engine 1 is released. In the fuel cut (fuel injection amount = 0) continued by prohibiting the fuel recovery in step S26, the engine is stopped as indicated by the engine speed Ne = 0 (step S26 and step S28).
This switches from HEV traveling to EV traveling, and EV regeneration is performed from instant t4.

In this EV regeneration, the regenerative braking force is added by the drag deceleration Gd of the engine 1 and the continuously variable transmission 4 during HEV regeneration obtained in step S27.
As a result, the power generated by the EV regeneration is increased by the drag deceleration Gd as seen after the instant t4 in FIG.
In this way, by adding the regenerative braking force during EV regeneration by the drag deceleration Gd of engine 1 and continuously variable transmission 4, even after switching to EV regeneration, as in HEV regeneration, And regenerative braking in which a predetermined deceleration according to the driving state is obtained.

<Effect>
According to the above-described regenerative braking control of the second embodiment, during HEV regeneration in response to the release of the accelerator pedal 19 (steps S21 and S22), when the brake switch ON time ΔT becomes equal to or longer than the predetermined time ΔTs (step S24). ), It is determined that a predetermined period has elapsed since the start of regenerative braking, and the release of the clutch CL (switching from HEV regeneration to EV regeneration with the engine 1 stopped) is permitted (step S25).
Release of the clutch CL (switching from HEV regeneration to EV regeneration with engine 1 stop) is later than when HEV regeneration starts (when accelerator pedal 19 is released) and is necessary to protect the starter motor It is permitted at a predetermined timing as early as possible.

For this reason, the clutch CL is not released immediately after starting HEV regeneration (switching from HEV regeneration to EV regeneration with the engine 1 stopped), and the driver is changing the accelerator while the accelerator is changing frequently. It was possible to prevent frequent engine restarts even in an operating environment where the frequency is high, and related to the durability of the starter motor 3 such that the starter motor 3 has reached the endurance start number of times early. Problems can be avoided and the starter motor 3 can be protected.

Even if the release of the clutch CL is permitted after the start of HEV regeneration (when the accelerator pedal 19 is released) (switching from HEV regeneration to EV regeneration with the engine 1 stopped), In order to command the permission at the prescribed timing as early as necessary for protection,
The clutch CL release timing (HEV regeneration → EV regeneration switching) is only delayed by the minimum time necessary to solve the problem related to the durability of the starter motor 3 from the start of HEV regeneration. The efficiency degradation is negligible and can be ignored.
Therefore, the regenerative braking control device for a hybrid vehicle according to the present embodiment can satisfy both the requirements related to protection of the starter motor 3 and the requirements related to energy regenerative efficiency in a highly balanced manner, and one of them is greatly sacrificed. Does not cause the problem of becoming.

<Configuration>
FIG. 8 is a regenerative braking control program similar to FIG. 3, showing a regenerative braking control device for a hybrid vehicle according to a third embodiment of the present invention.
Like the first embodiment, this embodiment also relates to the regenerative braking control of the hybrid vehicle having the drive system shown in FIG. 1 or FIG. 2 (a), but the case where the drive system is as shown in FIG. Expand the description.
Accordingly, in this embodiment, regenerative braking is performed immediately after the shift to coasting (inertia) traveling to release the accelerator pedal 19, even if the braking operation by depressing the brake pedal 16 is not performed.

In step S31 in FIG. 8 started during HEV traveling, it is checked whether or not coasting (inertia) traveling in which the accelerator pedal 19 is released from the accelerator opening APO.
Since this embodiment is based on the premise that regenerative braking is performed only by releasing the accelerator pedal 19, as described above, when it is determined in step S31 that the accelerator pedal 19 is not in the released state, the control is ended as it is. Exit from 8 control programs.

When it is determined in step S31 that the coasting (inertia) travel is performed with the accelerator pedal 19 released, the control proceeds to step S32 because the regenerative braking conditions are met, and the current driving condition based on the current HEV traveling is determined. Regenerative braking (HEV regeneration) is performed to obtain a predetermined deceleration.

In the next step S33, it is checked whether or not the continuation time of the accelerator pedal release, which is the regenerative braking condition, that is, the accelerator pedal release determination time ΔT (HEV regeneration time) in step S31 is equal to or longer than the predetermined time ΔTs. It is determined whether or not a predetermined period has elapsed since the start of.
Note that the predetermined time ΔTs is determined in the same manner as described above with reference to FIG. 4, and the clutch CL release timing (which can satisfy both the demand for improving the energy regeneration efficiency and the protection demand for the starter motor, which are in the trade-off relationship described above) This is the delay time from the accelerator pedal release start instant (HEV regeneration start instant) of (HEV regeneration → EV regeneration switching timing).

While it is determined in step S33 that the accelerator pedal release determination time ΔT (HEV regeneration time) is less than the predetermined time ΔTs, the control is returned to step S32, and the predetermined deceleration according to the driving state is maintained with the current HEV running. Continue HEV regeneration so that it can be obtained.
When it is determined in step S33 that the accelerator pedal release determination time ΔT (HEV regeneration time) is equal to or greater than the predetermined time ΔTs, the control proceeds to step S34 to permit the release of the clutch CL.
Therefore, step S33 and step S34 correspond to clutch release permission means in the present invention.

In the next step S35, fuel supply restart (fuel recovery) to the engine 1 that has been fuel cut as described above is prohibited and fuel cut is continued.
Therefore, step S35 corresponds to the fuel recovery prohibiting means in the present invention.

In step S36, drag deceleration Gd of engine 1 and continuously variable transmission 4 via clutch CL in the engaged state is calculated from CVT pulley ratio, engine speed Ne, and vehicle speed VSP.
Then, in step S37, the clutch CL is released under the condition that the HEV → EV mode switching condition is satisfied, and thereby, the engine 1 is stopped together with the fuel recovery prohibition (continuation of fuel cut) in step S35, thereby shifting to EV driving. Switch from HEV regeneration to EV regeneration.

By the way, if the regenerative braking in step S32 is continued even after switching to the EV regenerative operation, the regenerative braking here assumes HEV traveling that drags the engine 1 and the continuously variable transmission 4 through the clutch CL in the engaged state. Due to the regenerative braking, the vehicle deceleration is insufficient with respect to the request by the drag deceleration of the engine 1 and the continuously variable transmission 4.
Therefore, in step S38, the drag deceleration Gd of the engine 1 and the continuously variable transmission 4 obtained in step S36 is added to the regenerative braking force, and EV regeneration is performed so that the added regenerative braking force is obtained. Even after switching to regeneration, a predetermined deceleration according to the driving state is obtained under the current EV driving.

The regenerative braking in FIG. 8 will be described in detail below based on the time chart in FIG.
During HEV running with clutch CL engaged, release accelerator pedal 19 at instant t1 in FIG. 9 and shift to coasting (inertia) running with accelerator opening APO = 0 (step S31), supply of fuel to engine 1 Stop (fuel cut) and set the fuel injection amount to 0 as shown in FIG.

In this embodiment, only the release of the accelerator pedal 19 is used as a regenerative braking condition, so HEV regeneration is started at the accelerator pedal release instant t1 (step S32).
With this HEV regeneration, the electric motor 2 performs regenerative braking so as to obtain a predetermined deceleration according to the driving state during HEV traveling, so that power is generated as apparent from the generated power after the instant t1 in FIG. The vehicle speed VSP is gradually decreased and at the same time the battery charge state SOC is increased.

The HEV regeneration is continued until the instant t2 (step S33) when the accelerator pedal release determination time ΔT (HEV regeneration time) from the instant t1 reaches the predetermined time ΔTs.
From the instant t2 when the accelerator pedal release determination time ΔT (HEV regeneration time) from the instant t1 reaches the predetermined time ΔTs until the instant t3 from the instant t2 (step S33), the clutch CL that has been engaged until now is released and the engine 1 is released. Then, the fuel cut (fuel injection amount = 0) continued by prohibiting the fuel recovery in step S35, and the engine is stopped as indicated by the engine speed Ne = 0 (step S35 and step S37).
This switches from HEV traveling to EV traveling, and EV regeneration is performed from instant t3.

In this EV regeneration, the regenerative braking force is added by the drag deceleration Gd of the engine 1 and the continuously variable transmission 4 during the HEV regeneration obtained in step S36.
As a result, the power generated by the EV regeneration is increased by the drag deceleration Gd as seen after the instant t3 in FIG.
In this way, by adding the regenerative braking force during EV regeneration by the drag deceleration Gd of engine 1 and continuously variable transmission 4, even after switching to EV regeneration, as in HEV regeneration, And regenerative braking in which a predetermined deceleration according to the driving state is obtained.

<Effect>
According to the regenerative braking control of the third embodiment described above, the release time ΔT of the accelerator pedal 19, that is, the duration ΔT of HEV regeneration (step S31 and step S32) corresponding to the release of the accelerator pedal 19 is equal to or longer than the predetermined time ΔTs. In order to permit the release of the clutch CL (switching from HEV regeneration to EV regeneration with the stop of the engine 1) by determining that the predetermined period has elapsed since the start of regenerative braking (step S33). (Step S34),
Release of the clutch CL (switching from HEV regeneration to EV regeneration with engine 1 stop) is later than when HEV regeneration starts (when accelerator pedal 19 is released) and is necessary to protect the starter motor It is permitted at a predetermined timing as early as possible.

Other examples

<Configuration>
In each of the above embodiments, the case where the engine 1 is cranked by the starter motor 3 at the time of starting the engine has been described. However, instead of this, the case where the engine 1 is cranked as follows is also described. By applying the idea of the invention, similar actions and effects can be obtained.

In other words, in modern hybrid vehicles and idle stop vehicles, a normal alternator (generator) that is mounted by being coupled to the engine crankshaft is replaced with a motor / generator so that power running is possible. When the engine is restarted or when the engine is torque-assisted as necessary while the engine is running, the motor / generator may be configured to achieve the purpose by powering.

In the case of such a hybrid vehicle, the engine 1 may be cranked by powering of the motor / generator instead of the starter motor 3 when starting the engine.
The idea of the present invention can be applied to such a vehicle, and in this case, the same operation and effect as described above can be achieved.

In step S12 in FIG. 3 and step S23 in FIG. 6, the determination is made by turning on the brake switch 26. However, the determination during braking is not limited to this. For example, the brake pedal stroke amount or the brake fluid pressure sensor detection value, which is a physical amount that changes according to the operation, may be determined to be braking when the brake determination value is reached.

Claims

The engine is detachably drive-coupled to the wheels via a clutch, and by releasing the clutch, electric traveling only by the electric motor is possible, and by hybridizing the electric motor and the engine by engaging the clutch In a possible hybrid vehicle,
When performing regenerative braking by the electric motor in the hybrid traveling state, there is provided clutch release permission means for permitting release of the clutch after a predetermined period has elapsed since the start of the regenerative braking. Control device.
In the regenerative braking control device for a hybrid vehicle according to claim 1,
The releasable braking control device for a hybrid vehicle, wherein the clutch disengagement permitting means permits disengagement of the clutch after a lapse of the predetermined period after a lapse of a predetermined time from the start of the regenerative braking. .
In the regenerative braking control device for a hybrid vehicle according to claim 2,
The clutch release permission means permits the release of the clutch after a predetermined time has elapsed after a predetermined time has elapsed from the start of a brake operation for braking the vehicle. Control device.
In the regenerative braking control device for a hybrid vehicle according to claim 2,
The clutch release permission means permits release of the clutch after a predetermined time has elapsed after a predetermined time has elapsed since the accelerator release operation for setting the output command of the power source to less than 0. A regenerative braking control device for a hybrid vehicle.
In the regenerative braking control device for a hybrid vehicle according to any one of claims 1 to 4,
An engine starting motor for starting the engine;
The regenerative braking control device for a hybrid vehicle, wherein the predetermined period is a time such that the number of times of starting the engine starting motor is less than the number of durable starting times of the engine starting motor.
6. The fuel supply to the engine is interrupted by a fuel cut during regenerative braking in the hybrid running state, and the fuel supply to the engine is restarted by a fuel recovery when the engine speed decreases. In the regenerative braking control device for a hybrid vehicle described in item 1,
A fuel recovery prohibiting means is provided for continuing the fuel cut by prohibiting the fuel recovery upon receiving the clutch release permission by the clutch release permission means, and stopping the engine when the clutch is released. A regenerative braking control device for a hybrid vehicle.