JP3384332B2 - Control device for hybrid vehicle - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hybrid vehicle in which an internal combustion engine and an electric motor are combined, and more particularly to switching control of a main power source.

[0002]

2. Description of the Related Art Conventionally, a hybrid vehicle has been known in which an engine and an electric motor are combined in order to reduce exhaust emission, and which is driven by either or both driving forces. "
Some are disclosed on pages 39 to 52 of the June 1997 issue of VOL.46 No7.

Further, Japanese Patent Application No. 10-
When a clutch is provided between the engine and the motor and the vehicle is propelled only by the driving force of the motor as in Japanese Patent No. 79158, the clutch is released while the driving force of the engine or the engine and the motor is used. When propulsion is carried out, there is one that engages a clutch.

[0004]

However, in the latter conventional example described above, it is necessary to engage and disengage the clutch according to the running conditions of the vehicle. However, in the case of engaging, the rotational speed of the engine and the motor If they are fastened in a state where the rotation speeds do not match, the driving force suddenly changes and a shock is generated, which gives the driver and fellow passengers a feeling of strangeness.

On the other hand, if the clutch is engaged while slipping so that the engine speed matches the motor speed, the shock can be prevented, but the durability of the clutch is reduced, and Since there is an unavoidable delay in engagement due to slip during acceleration that requires a large driving force, there is a problem that the driving force does not rise as expected by the driver and rapid acceleration cannot be performed.

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to improve the durability of the clutch while preventing the engagement shock and the delay in the rising of the driving force.

[0007]

SUMMARY OF THE INVENTION A first aspect of the present invention is directed to a first motor which is connected to driving wheels to mainly propel a vehicle, an engine which is connected to the first motor through a clutch, and the engine. A second motor which is connected to the main motor to mainly start or generate electric power, a power switching means for selecting at least one of the first motor and the engine as a main drive source according to an operating state, and the power switching means. In a control device for a hybrid vehicle, which comprises a clutch control means for engaging the clutch when a driving force from an engine is selected, the clutch control means detects a required driving force for detecting a driving force required by a driver. Means and motor driving force detection means for detecting a driving force that can be generated by the first motor,
When the clutch control means selects a driving force from the engine and engages the clutch, the clutch control means includes a comparing means for comparing the required driving force with a possible driving force of the first motor. When the required driving force is larger than the generable driving force, the clutch is set to the intermediate capacity before engaging, while when the required driving force is smaller than the generable driving force, the input side and the output side of the clutch Fastening is performed after synchronizing the rotation speeds of.

According to a second aspect of the present invention, in the first aspect of the invention, the clutch control means drives the second motor to synchronize the rotation speeds of the input side and the output side of the clutch. Control the number of rotations.

In a third aspect based on the first aspect, the motor driving force detecting means changes the drive force that can be generated according to the state of the battery that drives the first motor.

In a fourth aspect based on the first aspect, the motor driving force detecting means changes the drive force that can be generated according to the state of the first motor.

In a fifth aspect based on the first aspect, the clutch control means, when the clutch is set to an intermediate capacity, the rotational speeds of the input side and the output side of the clutch until the engagement is completed. Prohibit synchronization.

Further, in a sixth aspect based on the first aspect, the clutch control means prohibits the rotation speed synchronization between the input side and the output side of the clutch when the vehicle speed is equal to or lower than a predetermined value.

In a seventh aspect based on the first aspect, the clutch control means prohibits the setting of the intermediate capacity when the clutch continues to slip.

[0014]

Therefore, according to the first aspect of the present invention, when the driving force required by the driver is larger than the drive force that can be generated by the first motor when the driving force from the engine is selected and the clutch is engaged, By setting the clutch to the intermediate capacity and then engaging the clutch, the driving torque from the engine can be quickly transmitted and the driving force according to the driver's expectation can be obtained. When the driving force that can be generated by the motor is smaller than that, the input and output speeds of the clutch are matched before being engaged, so that it is possible to reliably prevent a shock from occurring when the clutch is engaged. It is possible to improve drivability and riding comfort, and further, it is possible to suppress slippage of the clutch at the time of engagement, so that it is possible to suppress heat generation and improve durability.

The second aspect of the present invention drives the second motor to control the number of revolutions of the engine when synchronizing the number of revolutions on the input side and the output side of the clutch.
Since the motor regenerates the engine output, the input torque to the clutch can be reduced to 0, and it is possible to reliably prevent the shock from being generated when the clutch is engaged.

Further, according to the third aspect of the invention, the overdrive of the battery can be prevented and the durability can be improved by changing the drive power that can be generated according to the state of the battery that drives the first motor.

Further, according to the fourth aspect of the present invention, since the drive force that can be generated is changed according to the state of the first motor, it is possible to prevent overload of the first motor and prevent overheating.

Further, in the fifth aspect of the invention, after the clutch is set to the intermediate capacity and the engagement is started, the rotation speed synchronization between the input side and the output side of the clutch is prohibited until the engagement is completed. Hunting can be prevented.

Further, in the sixth aspect of the invention, when the vehicle speed is equal to or lower than a predetermined value, it is prohibited to synchronize and engage the rotational speeds of the input side and the output side of the clutch, and the engine stalls when the vehicle speed is low. It can be prevented from occurring.

Further, according to the seventh aspect of the present invention, when the clutch slips continuously, the setting of the intermediate capacity is prohibited to prevent overheating of the clutch and improve the durability.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an example of a hybrid vehicle to which the present invention can be applied, which is driven by using the driving force of either or both of an engine and an electric motor.

In FIG. 1, a thick solid line indicates a mechanical force transmission path, a broken line indicates an electric power path, a thin solid line indicates a control system, and a double line indicates a hydraulic system.

The power train of this vehicle includes a motor 1,
The engine 2, the clutch 3, the motor 4, the continuously variable transmission 5, the reduction gear 6 and the differential gear 7 and the drive wheels 8 are included. The output shaft of the motor 1, the output shaft of the engine 2, and the input shaft of the clutch 3 are connected to each other, and the output shaft of the clutch 3, the output shaft of the motor 4, and the input shaft of the continuously variable transmission 5 are connected to each other. ing.

At the time of engaging the clutch 3, at least one of the engine 2 and the motor 4 serves as a propulsion source for the vehicle, and when the clutch 3 is disengaged, only the motor 4 serves as a propulsion source for the vehicle. The driving force of the engine 2 or the motor 4 is transmitted to the drive wheels 8 via the continuously variable transmission 5, the reduction gear 6 and the differential gear 7.

Here, the clutch 3 is composed of, for example, a powder clutch, and can be set to an arbitrary clutch capacity (hereinafter referred to as intermediate capacity) between the released state and the engaged state. At the time of, the torque is transmitted while slipping the clutch 3, while at the time of engagement (maximum capacity), the torque is transmitted by connecting the input shaft and the output shaft.

Pressure oil is supplied to the continuously variable transmission 5 of the V-belt type or toroidal type from a pump (not shown) of the hydraulic device 9, and the pump is driven by a motor 10.

The motor 1 (second motor) is mainly used for starting the engine 2 and power generation, and the motor 4 (first motor) is mainly used for propulsion of the vehicle and energy regeneration.

Of course, when the clutch 3 is engaged, the motor 1 can be used for propulsion and regeneration of the vehicle.
Can also be used to start the engine 2 and generate electricity. The motors 1, 4 and 10 are composed of an AC machine and are connected to the battery 15 via the inverters 11 to 13, respectively.

The power train is controlled by a controller 16 mainly composed of a microcomputer. As shown in FIG. 2, the controller 16 has a vehicle speed VSP from a vehicle speed sensor 24 and an accelerator opening sensor 2 as shown in FIG.
The accelerator opening APS (or the amount of depression) from 2 and the engine speed Ne, C from the engine speed sensor 27
The input shaft speed Ni from the VT input shaft speed sensor 23,
A signal indicating the charge state is input from the battery charge state sensor 26.

The controller 16 determines the operating state based on the signals from these sensors, the motor control unit 30 controls the motor 1 via the inverter 11, and similarly, the fuel of the engine 2 via the engine control unit 31. Injection control and ignition timing control are performed, engagement and disengagement of the clutch 3 are controlled via the clutch control unit 32, the motor control unit 33 controls the motor 4 via the inverter 12, and the CVT control unit 34 controls the motor 10. And the hydraulic device 9 are used to perform shift control of the continuously variable transmission 5, respectively.

Here, an example of engagement control of the clutch 3 performed by the clutch control section 32 will be described in detail below with reference to the flowcharts of FIGS. In addition,
FIG. 3 shows a main routine of clutch engagement control, and FIG. 4 shows a subroutine for calculating the maximum drive torque TDAMAX of the motor 4 and the clutch engagement start drive torque TDCLON, which are executed at predetermined time intervals. It is a thing.

First, in step S1 of FIG.
After the information such as the accelerator opening APS, the engine speed Ne, the input shaft speed Ni, etc. is read from the various sensors shown in (1), the target drive torque TTD is calculated in step S2.

The calculation of this target drive torque TTD is shown in FIG.
As shown in, a target drive torque TTD corresponding to the vehicle speed VSP is calculated based on a preset map using the read accelerator opening APS as a parameter.

Next, in step S3, the maximum drive torque TDAMAX of the motor 4 is calculated from the subroutine of FIG. 4, and the engagement start drive torque TDCLON for starting the engine 2 and starting the engagement of the clutch 3 is calculated. To do.

In FIG. 4, the maximum drive torque TDAMAX of the motor 4 and the engagement start drive torque TD of the clutch 3 are shown.
The calculation of CLON is first performed in step S30 by the motor 4
Rotation speed NMA (= CVT input shaft rotation speed Ni), the torque limit value TMALIM of the motor 4 that changes according to the state of the inverter 12, and the maximum output PBMAX of the battery 15 that changes according to temperature and charging capacity. Then, in step S31, a torque limit value TMALIM that regulates the maximum torque limit value TMMAX of the motor 4 is calculated.

That is, the torque limit value TMALIM is
The maximum torque that can be generated by the motor 4 is regulated according to the state of the inverter 12 and the temperature of the motor 4.
The torque limit value TMALIM decreases as the temperature of the inverter 12 increases, and the maximum torque TMA of the motor 4 increases.
MAX is reduced.

Next, in step S32, as shown in FIG. 6, the maximum output PBMAX that varies according to the state of the battery 15 is calculated, and the maximum torque TMAM of the motor 4 is calculated.
AX is regulated so that the maximum output is within PBMAX.

Since the maximum output PBMAX of the battery 15 decreases as the remaining amount of electric power decreases and the temperature rises, the maximum torque TMMAX of the motor 4 is regulated so as to be within the maximum output PBMAX.

Then, in step S33, the maximum torque TMAX of the motor 4 regulated to the torque limit value TMALIM obtained in step S31 and the maximum output PBMAX of the battery 15 obtained in step S32 of the motor 4 are regulated. Of the maximum torque TMAX, the smaller one is set as the maximum torque TMAX of the motor 4 according to the current operating state.
As shown in FIG. 6, the value obtained by subtracting a predetermined margin ΔN from X is the clutch engagement start drive torque TMACLO.
Calculate as N.

The clutch engagement start drive torque TMA
Since CLON requires the driving force of the engine 2 in a predetermined high vehicle speed range, the CLON is set to engage the clutch 3 at a predetermined motor speed NMA or higher.

Then, in step S34, the maximum torque TMAX and the clutch engagement start drive torque TMACLON obtained in step S33 are multiplied by the gear ratio RATIO and the final reduction ratio Final respectively to obtain the maximum drive torque TDAMAX and the clutch engagement. It is calculated as the start drive torque TDCLON.

Here, the clutch engagement start drive torque TD
The relationship between CLON and the maximum drive torque TDAMAX is as shown in FIG. 7. When the target drive torque TTD exceeds the clutch engagement start drive torque TDCLON, the vehicle is driven by the output of the engine 2 instead of the motor 4, which will be described later. Such engagement control of the clutch 3 is performed.

Thus, the maximum drive torque TD of the motor 4
After obtaining AMAX and the clutch engagement start drive torque TDCLON, the process proceeds to step S4 in FIG.

In step S4, it is determined whether or not the target drive torque TTD obtained in step S2 exceeds the clutch engagement start drive torque TDCLON obtained in step S34, and the clutch engagement start drive torque TD is determined.
If it is larger than CLON, the process proceeds to the engagement control of the clutch 3 after step S5, while if not,
The process is terminated as it is.

In step S5, the slip fastening flag F
FSLIP = 1 by judging whether SLIP is 1 or not
If so, the process proceeds to step S8 because the slip engagement control is in progress, while if FSLIP = 0, the process proceeds to step S6.

At step S6, the target drive torque TTD
Is greater than the maximum drive torque TDAMAX, the target drive torque TTD is equal to the maximum drive torque TDA.
If it exceeds MAX, the routine proceeds to step S8, where the slip engagement flag FSLIP is set to 1, and then the slip engagement control is performed at step S9 while the target drive torque T
When TD is equal to or less than the maximum drive torque TDAMAX, the process proceeds to step S7, and the synchronous engagement control described later is performed.

Then, step S7 or step S9
Then, after performing the fastening control by synchronization or slip, it is determined in step S10 whether or not the fastening is completed based on the engine speed Ne = the input shaft speed Ni. If the fastening is completed, the step is performed. While proceeding to S11, the slip flag FSLIP is cleared to 0 and the processing is ended. On the other hand, when the fastening is not finished, the processing is finished as it is, the current value of the slip fastening flag FSLIP is held, and the next time. To prepare for fastening control.

By executing the above control, as shown in FIG. 7, the target drive torque TTD corresponding to the vehicle speed VSP.
Exceeds the clutch engagement start drive torque TDCLON, the drive by the motor 4 is switched to the drive by the engine 2, and when the target drive torque TTD changes to a range equal to or less than the maximum drive torque TDAMAX, the engine 2 is driven by the motor 1. After the start, the synchronous drive control in which the clutch 1 is engaged while the motor 1 is regenerating is selected, while the target drive torque TTD is the maximum drive torque TDA.
When changing to a region exceeding MAX, slip engagement control is selected in which the engine 1 is started by the motor 1 and then gradually engaged using the intermediate capacity of the clutch 3.

Next, the synchronous engagement control and the slip engagement control will be described in detail with reference to FIGS. 8 and 9.

First, in the synchronous engagement control using the regeneration of the motor 1, as shown in FIG. 8, the clutch 3 is released and only the motor 4 is operated until the time t0 when the start of the synchronous engagement control is judged in step S7. Cars are being promoted.

When the synchronous engagement control is started at time t0, first, the motor 1 is driven to start cranking the engine 2.

The driving of the engine 2 by the motor 1 is performed until the time t1 when the engine 2 completes the explosion. When the engine 2 completes the explosion and the engine speed Ne starts to increase, the motor 1 is driven in the regenerative direction. , The sum of the engine torque Te and the torque TMB of the motor 1 is controlled to be 0, and the input torque of the clutch 3 is 0.

Next, by the regeneration of the motor 1, the released clutch 3 is engaged at the time t2 when the engine speed Ne matches the input shaft speed Ni of the continuously variable transmission 5.

On the other hand, from time t3, the regeneration of the motor 1 is gradually reduced and the driving torque TD of the motor 4 is increased.
By gradually decreasing A as well, the sum of the drive torques of the motor 1, the motor 4, and the engine 2 becomes the target drive torque T.
It is consistent with TD.

After time t4, the drive torque TMB of the motor 1 and the drive torque TDA of the motor 4 both become 0, and the vehicle is propelled only by the torque Te of the engine 2.

Thus, when the power source is switched from the motor 4 to the engine 2, if the accelerator opening APS target drive torque TTD exceeds the clutch engagement start drive torque TDCLON within the maximum drive torque TDAMAX, after the engine 2 is started, Motor 1 regenerates and clutch 3
In addition to setting the input torque to 0, the engine speed N
Since the clutch 3 is engaged after e is matched with the input shaft rotation speed Ni, it is possible to reliably prevent a shock from being generated when the clutch is engaged, thereby improving drivability and riding comfort. Further, since the slippage of the clutch 3 can be suppressed at the time of engagement, the durability can be improved.

From the start to the end of engagement of the clutch 3, the input torque to the continuously variable transmission 5 is not interrupted and changes smoothly, so that the driver does not feel uncomfortable and the drivability is improved. It can be improved.

Next, the slip engagement control for engaging the clutch 3 from the intermediate capacity when the target drive torque TTD changes to a region exceeding the maximum drive torque TDAMAX is shown in FIG.
As shown in FIG. 5, when the slip engagement flag FSLIP becomes 1 in step S8, it is determined that engagement is started, and the clutch 3 is released and the vehicle is propelled only by the motor 4 until the time t0.

When the slip engagement control is started at time t0, first, the motor 1 is driven to start the cranking of the engine 2.

The driving of the engine 2 by the motor 1 is performed until the time t1 when the engine 2 completes the explosion, and the time t1 when the engine 2 completes the explosion and the engine speed Ne starts to increase.
At the same time when the driving of the motor 1 is completed,
From the above, the clutch 3 set to a predetermined intermediate capacity gradually increases the clutch capacity and gradually transmits the engine torque Te to the continuously variable transmission 5.

On the other hand, the motor 4 generates a torque that is the difference between the target drive torque TTD and the clutch capacity from the time t1, and the motor 4 is driven at the time t2 when the engine speed Ne and the input speed Ni match. At the same time as the end, the clutch 3 that has been gradually engaged with the intermediate capacity (half clutch state) is completely engaged.

Time t when the clutch 3 is set to the intermediate capacity
From 1 to t2, the excessive engine torque Te that exceeds the target drive torque is absorbed (heated) by the clutch 3.

Therefore, after the time t2, the drive torque TDA of the motor 4 becomes 0, and the torque T of the engine 2 is reduced.
The vehicle is propelled only by e.

Thus, when the power source is switched from the motor 4 to the engine 2, if the target drive torque TTD is equal to or greater than the current value, the clutch 3 is engaged while increasing the intermediate capacity, so the engine speed Ne is increased. Can be quickly matched to the input shaft rotation speed Ni to increase the driving torque according to the driver's expectation, and the drivability can be improved.

As described above, when the main power source is switched from the motor 4 to the engine 2, the target drive torque TTD required by the driver exceeds the clutch engagement start drive torque TDCLON in a region smaller than the maximum drive torque TDAMAX. If the torque changes, the engine 2 is started by the synchronous engagement control and then the input torque to the clutch 3 is set to 0 by the regeneration of the motor 1 before the engagement. It is possible to suppress the slippage, reduce heat generation, and improve durability.

On the other hand, the target drive torque T required by the driver
When the TD changes to a region larger than the maximum drive torque TDAMAX, the clutch 3 is set to the intermediate capacity and then gradually engaged by the slip engagement control, so that the drive torque from the engine 2 can be quickly supplied. This can be transmitted to obtain the driving force that meets the driver's expectations.

Further, the maximum drive torque TDA of the motor 4
Maximum output PBM according to the state of the battery 15 MAX
Since the AX is regulated based on the torque limit value TMALIM according to the states of the motor 4 and the inverter 12, the battery 15 is prevented from being over-discharged, and the motor 4 and the inverter 12 are prevented from being overheated to improve durability. Therefore, the drivability and durability of the hybrid vehicle can be improved.

Further, once the slip engagement control is selected, the control does not shift to the synchronous engagement control, so that the control hunting can be prevented.

In the above embodiment, only the driving torque is used as the start condition for the synchronous engagement control, but although not shown,
By prohibiting synchronous fastening control at a prescribed vehicle speed or less,
It is possible to prevent engine stalling at low vehicle speeds.

Further, since the heat generation of the clutch 3 may be excessive under operating conditions where the slip engagement control is continuous, under such operating conditions, for example, the temperature of the clutch 3 exceeds a predetermined value. During the period, the slip engagement control may be temporarily prohibited and only the synchronous engagement control may be performed to suppress the heat generation of the clutch 3.

Further, as the clutch 3, instead of the powder clutch, a single plate clutch, a multi-plate clutch or the like having a variable engagement capacity may be appropriately adopted.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a hybrid vehicle showing an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a controller.

FIG. 3 is a flowchart showing an example of clutch engagement control.

FIG. 4 is a flowchart of a subroutine showing calculation of a maximum drive torque of a motor and a clutch engagement start drive torque.

FIG. 5 is a map of target drive torque corresponding to vehicle speed with accelerator opening as a parameter.

FIG. 6 is a graph showing an example of the maximum drive torque of the motor and the clutch engagement start drive torque, showing the relationship between the vehicle speed and the torque.

FIG. 7 is a graph showing the relationship among vehicle speed, target drive torque, maximum drive torque, and clutch engagement start drive torque.

FIG. 8 is a time chart showing a state of synchronous engagement control,
The relationship between accelerator opening, input speed, clutch capacity, engine torque, drive torque, and time is shown.

FIG. 9 is a time chart showing the state of slip engagement control, showing the relationship between accelerator opening, input speed, clutch capacity, engine torque, drive torque, and time.

[Explanation of symbols]

1, 4 motor 2 engine 3 clutch 5 continuously variable transmission 12 inverter 15 battery 16 controller

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI B60K 6/04 551 B60K 6/04 731 731 41/00 301A 41/00 301 301B 301C 41/02 ZHV 41/02 ZHV B60L 11 / 14 B60L 11/14 15/20 S 15/20 F16D 25/14 640A F16D 48/06 640K 37/02 A (56) References JP-A-11-178110 (JP, A) JP-A-8-98322 (JP , A) JP 9-284911 (JP, A) JP 2000-71815 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F16D 48/00-48/12 F16D 37 / 02 B60K 6/02-6/06 B60K 41/00-41/28 B60L 11/02-11/14 B60L 15/20

Claims (7)

(57) [Claims] 1. A first motor, which is connected to driving wheels to mainly propel a vehicle, an engine which is connected to the first motor via a clutch, and which is connected to the engine to mainly start or A second motor for generating power, a power switching means for selecting at least one of the first motor and the engine as a main drive source in accordance with an operating state, and the power switching means for selecting a driving force from the engine In a control device for a hybrid vehicle, further comprising: a clutch control unit that engages the clutch, the clutch control unit includes a required driving force detection unit that detects a required driving force of a driver, and the first motor can be generated. Driving force detection means for detecting various driving forces, and the clutch control means selects the driving force from the engine and engages the clutch to drive the required driving force. And a comparing means for comparing the drive force that can be generated by the first motor with each other, and if the comparison result shows that the required drive force is larger than the drive force that can be generated, the clutch is set to an intermediate capacity before engaging. On the other hand, when the required driving force is smaller than the generable driving force, the hybrid vehicle control device is characterized in that the engagement is performed after synchronizing the rotational speeds of the input side and the output side of the clutch. 2. The clutch control means drives the second motor to control the engine speed when synchronizing the input and output speeds of the clutch. A control device for a hybrid vehicle according to 1. 3. The control device for a hybrid vehicle according to claim 1, wherein the motor drive force detection means changes the drive force that can be generated according to the state of the battery that drives the first motor. 4. The control device for a hybrid vehicle according to claim 1, wherein the motor drive force detection means changes the drive force that can be generated according to the state of the first motor. 5. The clutch control means, when the clutch is set to an intermediate capacity, prohibits the rotation speed synchronization between the input side and the output side of the clutch until engagement is completed. A control device for the hybrid vehicle described. 6. The hybrid vehicle control according to claim 1, wherein the clutch control means prohibits the rotation speed synchronization between the input side and the output side of the clutch when the vehicle speed is equal to or lower than a predetermined value. apparatus. 7. The control device for a hybrid vehicle according to claim 1, wherein the clutch control means prohibits setting of the intermediate capacity when the clutch slips continuously.