JP2000071815A - Controller for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability of a clutch while preventing fastening shock and delay in a rise of driving force. SOLUTION: This controller is provided with a motor 4 which is connected to a driving wheel 8 and mainly propels a vehicle, an engine 2 connected to the motor 4 through a clutch 3, and a motor 1 which is connected to the engine 2 and mainly starts it or generates its power. If the required driving force of a driver is larger than the generatable driving force of the motor 4 at the time of switching the motor 4 to the driving force of the engine 2, the clutch 3 is set to middle capacity for fastening. If the required driving force is smaller than the generatable driving force, the rotational speed on the input side of the clutch 3 is synchronized with that on the output side for fastening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 Hitherto, a hybrid vehicle has been known in which an engine and an electric motor are combined to run by one or both driving forces in order to reduce exhaust emissions. "
VOL. 46 No. 7, June 1997, pp. 39-52.

Further, Japanese Patent Application No. Hei 10-1998 proposed by the present applicant.
No. 79158, when a clutch is interposed between an engine and a motor and the propulsion of the vehicle is performed only by the driving force of the motor, the clutch is released and the vehicle is driven by the driving force of the engine or the engine and the motor. In some cases, the clutch is engaged.

[0004]

However, in the latter conventional example, it is necessary to engage and disengage the clutch in accordance with the running conditions of the vehicle. If the fastening is performed in a state where the rotation speeds do not match, the driving force changes suddenly, causing a shock and giving a sense of discomfort to the driver and the passenger.

On the other hand, if the clutch is engaged while slipping so that the engine speed and the motor speed match, the occurrence of a shock can be prevented, but the durability of the clutch is reduced, and At the time of acceleration that requires a large driving force, a fastening delay due to slip is inevitable, so that the driving force does not rise as expected by the driver, and there is a problem that rapid acceleration cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to improve the durability of a clutch while preventing an engagement shock and a delay in rising of a driving force.

[0007]

According to a first aspect of the present invention, there is provided a first motor connected to driving wheels for mainly propelling a vehicle, an engine connected to the first motor via a clutch, and an engine connected to the first motor. A second motor mainly connected to the motor for starting or generating power of the engine, power switching means for selecting at least one of the first motor and the engine as a main drive source in accordance with an operation state, and the power switching means And a clutch control means for engaging the clutch when a driving force from the engine is selected, wherein the clutch control means detects a required driving force of a driver. Means, motor driving force detecting means for detecting a driving force that can be generated by the first motor,
When the clutch control means selects a driving force from an engine and engages a clutch, the clutch control means includes a comparison means for comparing the required driving force with a driving force that can be generated by the first motor, and the comparison result is If the required driving force is larger than the possible driving force, the clutch is set to the intermediate capacity before engaging.On the other hand, if the required driving force is smaller than the possible driving force, the input and output sides of the clutch are set. After the number of rotations is synchronized, the fastening is performed.

According to a second aspect of the present invention, in the first aspect, the clutch control means drives the second motor to synchronize the engine speed when synchronizing the rotational speeds of the input side and the output side of the clutch. Control the speed.

In a third aspect based on the first aspect, the motor driving force detecting means changes a possible driving force in accordance with a state of a battery for driving the first motor.

In a fourth aspect based on the first aspect, the motor driving force detecting means changes the possible driving force in accordance with 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 number of rotations of the input and output sides of the clutch until the engagement is completed. Prohibit synchronization.

In a sixth aspect based on the first aspect, the clutch control means prohibits synchronization of the rotational speeds of 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 slip of the clutch continues.

[0014]

Accordingly, the first aspect of the present invention provides a method for selecting a driving force from the engine and engaging the clutch, when the driver's required driving force is larger than the driving force that can be generated by the first motor. By setting the clutch to the intermediate capacity and then engaging the clutch, the driving torque from the engine can be quickly transmitted to obtain a driving force according to the driver's expectation. When the driving force that can be generated by the motor is smaller than that, the clutch is engaged after the input and output rotation speeds are matched, so that it is possible to reliably prevent a shock from occurring when the clutch is engaged. Drivability and riding comfort can be improved, and further, slippage of the clutch can be suppressed at the time of engagement, so that heat generation can be suppressed and durability can be improved.

In the second invention, when synchronizing the rotational speeds on the input side and the output side of the clutch, the second motor is driven to control the rotational speed of the engine.
When the motor regenerates the engine output, the input torque to the clutch can be reduced to zero, and it is possible to reliably prevent a shock from occurring when the clutch is engaged.

According to the third aspect of the present invention, by changing the driving force that can be generated according to the state of the battery that drives the first motor, overdischarge of the battery can be prevented and durability can be improved.

According to the fourth aspect of the present invention, the drive power that can be generated is changed according to the state of the first motor. For example, overheating of the first motor can be prevented by preventing overheating of the first motor.

According to a fifth aspect of the present 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 inhibited until the engagement is completed, thereby controlling the clutch. Hunting can be prevented.

According to a sixth aspect of the present invention, when the vehicle speed is equal to or lower than a predetermined value, the clutches are prohibited from synchronizing and engaging the rotational speeds of the input side and the output side of the clutch. It can be prevented from occurring.

According to the seventh aspect of the present invention, when the slip of the clutch is continuous, the setting of the intermediate capacity is prohibited, so that the overheating of the clutch can be prevented and the durability can be improved.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One 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. The hybrid vehicle travels by using one or both of an engine and an electric motor.

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

The power train of this vehicle is comprised of a motor 1,
The engine 2 includes a clutch 3, a motor 4, a continuously variable transmission 5, a speed reducer 6, a differential 7, and drive wheels 8. 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.

When the clutch 3 is engaged, at least one of the engine 2 and the motor 4 serves as a propulsion source for the vehicle. When the clutch 3 is released, 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 driving 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 an intermediate capacity) from the released state to the engaged state. In the case of, the torque is transmitted while the clutch 3 is slipping, and at the time of engagement (maximum capacity), the input shaft and the output shaft are connected to transmit the torque.

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

The motor 1 (second motor) is mainly used for starting and power generation of the engine 2, 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 be used for starting the engine 2 and generating power. The motors 1, 4, and 10 are constituted by AC machines, and are connected to the battery 15 via 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.
2, the accelerator opening APS (or the amount of depression) from 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 state of charge is input from the battery state-of-charge 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. It performs injection control and ignition timing control, controls engagement and disengagement of the clutch 3 via a clutch control unit 32, a motor control unit 33 controls the motor 4 via the inverter 12, and a CVT control unit 34 controls the motor 10 And the shift control of the continuously variable transmission 5 via the hydraulic device 9.

Here, an example of the 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 a maximum drive torque TDAMAX of the motor 4 and a clutch engagement start drive torque TDCLON, each of which is executed at predetermined time intervals. Things.

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

The calculation of the target drive torque TTD is shown in FIG.
As shown in (5), a target drive torque TTD corresponding to the vehicle speed VSP is calculated using the read accelerator opening APS as a parameter based on a preset map.

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. I do.

In FIG. 4, the maximum drive torque TDAMAX of the motor 4 and the engagement start drive torque TD of the clutch 3
First, the CLON calculation is performed in step S30.
Such as the rotation speed NMA (= CVT input shaft rotation speed Ni), the torque limit value TMALIM of the motor 4 that varies according to the state of the inverter 12, and the maximum output PBMAX of the battery 15 that varies according to the temperature and the charging capacity. Is read, and in step S31, a torque limit value TMALIM for regulating the maximum torque limit value TMAX of the motor 4 is calculated.

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

Next, in step S32, as shown in FIG. 6, a 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 as to be within the maximum output PBMAX.

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

In step S33, the maximum torque TMAX of the motor 4 regulated by the torque limit value TMALIM calculated in step S31 and the maximum torque PBMAX of the battery 15 determined in step S32 are calculated. Of the maximum torques TMAX, the smaller one is set as the maximum torque TMAX of the motor 4 according to the current operation state.
X minus a predetermined margin ΔN is applied to the clutch engagement start drive torque TMACLO as shown in FIG.
Calculate as N.

The clutch engagement start drive torque TMA
CLON is set so that the clutch 3 is engaged at a predetermined motor speed NMA or more because the driving force of the engine 2 is required in a predetermined high vehicle speed range.

In step S34, the maximum drive torque TDAMAX and the clutch engagement are obtained by multiplying the maximum torque TMAX and the clutch engagement start drive torque TMACLON obtained in step S33 by the speed ratio RATIO and the final reduction ratio Final, respectively. 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 driving torque TD of the motor 4
After obtaining the AMAX and the clutch engagement start drive torque TDCLON, the process proceeds to step S4 in FIG.

In step S4, it is determined whether 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.
When it is larger than CLON, the process proceeds to the engagement control of the clutch 3 after step S5.
The process ends as it is.

In step S5, the slip engagement flag F
It is determined whether or not SLIP is 1, and FSLIP = 1
If so, the flow proceeds to step S8 because the slip engagement control is being performed, whereas if FSLIP = 0, the flow proceeds to step S6.

In step S6, the target drive torque TTD
Is larger than the maximum drive torque TDAMAX, and the target drive torque TTD is determined to be larger than the maximum drive torque TDAMAX.
If it exceeds MAX, the routine proceeds to step S8, in which the slip engagement flag FSLIP is set to 1, and then, in step S9, the slip engagement control is performed, while the target drive torque T
If the TD is equal to or less than the maximum drive torque TDAMAX, the process proceeds to step S7 to perform a synchronous engagement control described later.

Then, step S7 or step S9
After performing the engagement control by synchronization or slip, it is determined in step S10 whether or not the engagement has been completed based on the engine speed Ne = the input shaft speed Ni. Proceeding to S11, the slip flag FSLIP is cleared to 0, and the process is terminated. On the other hand, if the engagement is not completed, the process is terminated as it is, the current value of the slip engagement flag FSLIP is held, and the next time. In preparation for the engagement control.

By executing the above control, as shown in FIG. 7, the target drive torque TTD corresponding to the vehicle speed VSP is obtained.
Exceeds the clutch engagement start drive torque TDCLON, the drive is switched from the drive by the motor 4 to the drive by the engine 2, and when the target drive torque TTD changes to a region equal to or less than the maximum drive torque TDAMAX, the engine 1 is driven by the motor 1. After starting, synchronous engagement control for engaging the clutch 3 while performing regeneration by the motor 1 is selected, while the target drive torque TTD is set to the maximum drive torque TDA.
In the case of a change to a region exceeding MAX, after the engine 2 is started by the motor 1, the slip engagement control that gradually engages using the intermediate capacity of the clutch 3 is selected.

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

First, in the synchronous engagement control using the regeneration of the motor 1, as shown in FIG. 8, the clutch 3 is released and the motor 4 alone is used until the time t0 when the start of the synchronous engagement control is determined in the step S7. The vehicle is being propelled.

When the synchronous 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 completely explodes. When the engine 2 completely explodes and the engine speed Ne starts to increase, the motor 1 is driven in the regenerative direction. Is controlled so that the sum of the engine torque Te and the torque TMB of the motor 1 becomes zero, and the input torque of the clutch 3 becomes zero.

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

On the other hand, from the time t3, the regeneration of the motor 1 is gradually reduced and the driving torque TD of the motor 4 is reduced.
A is also gradually reduced, so that the sum of the driving torques of the motor 1, the motor 4 and the engine 2 becomes the target driving torque T
It is consistent with TD.

After time t4, the driving torque TMB of the motor 1 and the driving torque TDA of the motor 4 are both 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, the engine 2 is started. Motor 1 regenerates and clutch 3
In addition to making the input torque of the engine zero, the engine speed N
Since the clutch 3 is engaged after e is made equal to the input shaft rotation speed Ni, it is possible to reliably prevent a shock from occurring when the clutch is engaged, and to improve drivability and riding comfort. In addition, since the slip of the clutch 3 can be suppressed at the time of engagement, the durability can be improved.

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

Next, when the target driving torque TTD changes to a region exceeding the maximum driving torque TDAMAX, the slip engagement control for engaging the clutch 3 from the intermediate capacity is performed as shown in FIG.
As shown in (5), when the slip engagement flag FSLIP becomes 1 in step S8, it is determined that the engagement has been started. Until the time t0, the clutch 3 is released and the propulsion of the vehicle is performed only by the motor 4.

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 completely explodes, and the time t1 when the engine 2 completely explodes and the engine speed Ne starts to increase.
At the same time when the driving of the motor 1 is completed,
After that, the clutch 3 set to the 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 difference between the target drive torque TTD and the clutch capacity from the time t1, and the drive of the motor 4 is stopped at the time t2 when the engine speed Ne matches the input speed Ni. At the same time, the clutch 3 gradually engaged with the intermediate capacity (half-clutch state) is completely engaged.

Time t during which clutch 3 is set to the intermediate capacity
From 1 to t2, the excessive engine torque Te exceeding 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 TDA of the engine 2 becomes zero.
The vehicle is propelled only by e.

When the power source is switched from the motor 4 to the engine 2 and the target drive torque TTD is equal to or more than the current value, the clutch 3 is engaged while the intermediate capacity is increased, so that the engine speed Ne is increased. Is quickly matched with the input shaft rotation speed Ni, the drive torque can be increased according to the driver's expectation, and the drivability can be improved.

As described above, when switching the main power source 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. In this case, after the engine 2 is started by the synchronous engagement control, the input torque to the clutch 3 is reduced to zero by the regeneration of the motor 1 before the engagement is performed. Can be suppressed, heat generation can be reduced, and durability can be improved.

On the other hand, the target driving 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 is quickly increased. The driving force can be obtained according to the driver's expectation.

Further, the maximum driving torque TDA of the motor 4
MAX is a maximum output PBM according to the state of the battery 15.
The AX and the torque limit value TMALIM according to the state of the motor 4 and the inverter 12 are regulated to prevent overdischarge of the battery 15 and improve durability by preventing overheating of the motor 4 and the inverter 12. And the drivability and durability of the hybrid vehicle can be improved.

Further, once the slip engagement control is selected, there is no transition to the synchronous engagement control, so that hunting of the control can be prevented.

In the above embodiment, only the driving torque is used as the condition for starting the synchronous engagement control.
At a predetermined vehicle speed or less, by prohibiting the synchronous engagement control,
An engine stall can be prevented from occurring at low vehicle speeds.

Further, under operating conditions in which the slip engagement control is continuous, the heat generated by the clutch 3 may be excessive. Under such operating conditions, for example, the temperature of the clutch 3 exceeds a predetermined value. During this time, 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.

As the clutch 3, instead of the powder clutch, a clutch capable of changing the engagement capacity, such as a single-plate clutch or a multiple-plate clutch, may be used as appropriate.

[Brief description of the drawings]

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

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

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

FIG. 4 is a flowchart of a subroutine showing calculation of a maximum driving torque of a motor and a driving torque for starting clutch engagement.

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

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

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

FIG. 8 is a time chart showing a state of synchronous engagement control;
The relationship between accelerator opening, input rotation 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 rotation 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

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) EA13 EB08 EC01 EC04 FA07 FB05 5H115 PA01 PG04 PI13 PI29 PU01 PU22 PU27 PU29 QN02 QN06 SE04 SE05 SE09 TB01 TE02 TI01 TO04 TO21 TU12 TU17

Claims (7)

[Claims] 1. A first motor connected to driving wheels and mainly propelling a vehicle; an engine connected to the first motor via a clutch; and an engine mainly connected to the engine for starting or starting the engine. A second motor for generating electric power, power switching means for selecting at least one of a first motor and an engine as a main drive source according to an operation state, and when the power switching means selects a driving force from the engine. A control device for a hybrid vehicle, comprising: clutch control means for engaging the clutch; wherein the clutch control means includes: a required driving force detection means for detecting a required driving force of a driver; and the first motor can be generated. A motor driving force detecting means for detecting a driving force, the clutch control means selecting a driving force from an engine to engage the clutch, and And a comparing means for comparing the generated driving force with the first motor. If the comparison result shows that the required driving force is larger than the generated driving force, the clutch is set to the intermediate capacity and the engagement is established. On the other hand, if the required driving force is smaller than the possible driving force, the control is performed after synchronizing the rotational speeds of the input side and the output side of the clutch, and then performing the engagement. 2. The system according to claim 1, wherein the clutch control means controls the engine speed by driving the second motor when synchronizing the speeds of the input side and the output side of the clutch. 3. The control device for a hybrid vehicle according to claim 1. 3. The hybrid vehicle control device according to claim 1, wherein said motor driving force detecting means changes a driving force that can be generated according to a state of a battery that drives the first motor. 4. The control device for a hybrid vehicle according to claim 1, wherein said motor driving force detection means changes a driving force that can be generated according to a state of the first motor. 5. The clutch control device according to claim 1, wherein when the clutch is set to an intermediate capacity, the clutch control unit prohibits synchronization of the rotational speeds of the input side and the output side of the clutch until the engagement is completed. A control device for a hybrid vehicle according to any one of the preceding claims. 6. The control of a hybrid vehicle 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 hybrid vehicle control device according to claim 1, wherein the clutch control unit prohibits the setting of the intermediate capacity when the clutch slips continuously.