JP2970427B2 - Control device for series parallel composite electric vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a series hybrid vehicle (SHV) and a parallel hybrid vehicle (PH).
The present invention relates to a series-parallel hybrid electric vehicle (SPHV) that can also be driven as V), and particularly to a control device thereof.

[0002]

2. Description of the Related Art A hybrid vehicle (HV) is an example of a system configuration of an electric vehicle, and is characterized by mounting an engine in addition to a motor. Among the HVs, those called SHVs have a configuration in which a generator is driven by a mechanical output of an engine, a motor is driven by a power output of the generator and a discharge output of a battery, and wheels are driven by the motor. In addition, the battery mounted on the SHV is charged not only by the regenerative power of the motor and the power from the external power source, but also by the power generation output of the generator.

[0003] As the HV, there is a so-called PHV. PHV is a vehicle that drives wheels by the mechanical output of the engine. When starting, accelerating, braking, etc.
It has a configuration in which the difference between the mechanical output of the engine and the required output is compensated by a rotating machine provided on the shaft of the engine, that is, a configuration in which acceleration and deceleration are performed. In this configuration, acceleration is realized by operating the rotating machine as a motor, and deceleration is realized by operating the rotating machine as a generator. A vehicle-mounted battery supplies power to or regenerates power from a rotating machine.

[0004] In any of these configurations, fuel efficiency and emission can be improved as compared with a conventional vehicle having only an engine. That is, the engine is fully throttled (WOT)
, The thermal efficiency of the engine can be maximized, and the fuel efficiency can be improved.
Further, since the excess or deficiency of the power generation output of the generator can be compensated by charging and discharging the battery, the rate of change of the engine speed can be suppressed, and the emission of the engine can be improved.

As the HV, a system configuration in which the SHV and the PHV are combined, that is, the SHV
SPH that can be run as a car or PHV
V is known (see Japanese Utility Model Application Laid-Open No. Sho 51-103220 and JP-A-4-297330). In this type of system,
The generator and the motor are mechanically connected to each other so as to be openable and closable by a mechanism such as a clutch. That is, when the vehicle runs with the SPHV as the SHHV, the clutch is opened to disconnect the mechanical connection between the generator and the motor. Then, the power output of the generator driven by the engine is supplied to the motor via the battery. This state is equivalent to SHV. Conversely, SP
When the HV runs as a PHV, the clutch is closed and the generator and the motor are mechanically connected. Then, the mechanical output of the engine is mechanically transmitted to the drive wheels via the generator, the clutch and the motor, and the engine can be accelerated and decelerated using the generator and the motor. This state is PH
It is equivalent to V.

[0006]

As a method of extending the life of a battery, there is known a method of managing a state of charge (SOC) within a predetermined range. In SHV, this management can be realized by generator control. SP
Even in the case of the HV, the same control can be executed during the SHV traveling, so that the same advantage can be enjoyed. However, during PHV traveling, the excess and deficiency with respect to the required output torque must be covered by the generator and the motor. The control for this is basically the target control of the output, so that it is not compatible with the generator output control for SOC management involving the operation of the charge / discharge power of the battery. Therefore, if the PHV running is continued for a long time, the battery may be overcharged or overdischarged.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and performs SOC management under a predetermined condition even during PHV driving, whereby
It is an object of the present invention to prevent the battery from being overcharged or overdischarged even when the PHV traveling continues for a long time.

[0008]

In order to achieve the above object, the present invention provides an engine, a generator driven by a mechanical output of the engine, a battery charged by the power output of the generator, In a SPHV having a motor driven by a discharge output of a battery and connection opening / closing means for opening / closing a mechanical connection between the generator and the motor, the mechanical connection between the generator and the motor is opened by the connection opening / closing means. , S
Means for running the PHV as an SHV, and closing the mechanical connection between the generator and the motor by the connection opening / closing means, while using at least one of the generator and the motor for acceleration / deceleration,
Means for running the SPHV as a PHV, and the SPH when the SOC of the battery is outside the first control target range.
Means for forcibly driving V as SHV.

[0009] The present invention further forcibly reduces the SPHV when the SOC of the battery falls within the second control target range included in the first control target range as a result of forcibly driving the SPHV as the SHHV. It is characterized in that the control for causing the vehicle to run as the SHV is ended.

The present invention is also characterized in that the control for forcibly driving the SPHV as the SHHV is terminated after a predetermined time has elapsed after the forcible running of the SPHV as the SHHV is started.

[0011]

In the present invention, forcible SHV traveling is performed when the SOC of the battery is outside the first control target range. Therefore, even if PHV traveling is continued for a long time, the SOC management of the battery is performed at a certain frequency, so that overcharging or overdischarging of the battery is prevented.

Further, in the present invention, compulsory SHV
When the SOC of the battery recovers within the second control target range due to the traveling, the forced SHV traveling ends. At this time, since the second control target range is included in the first control target range,
Hysteresis occurs in the SOC control. By providing the hysteresis in this manner, the forced SHV traveling is not frequently performed repeatedly due to the change in the SOC, and frequent opening and closing of the connection opening / closing means is prevented.

In the present invention, alternatively, the forced SH
After a lapse of a predetermined time from the start of the V running, the forced SHV running is terminated. If the forced SHV traveling is continued for a certain period of time, the SOC recovers to some extent. In addition, by continuing the forced SHV traveling for a predetermined time, the forced SHV traveling is not frequently performed repeatedly due to the change in the SOC, and frequent opening and closing of the connection opening / closing means is prevented.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

(1) System configuration of serial type SPHV FIG. 1 shows a system configuration of an SPHV according to a first embodiment of the present invention. The system shown in this figure is
This is a series SPHV in which the engine 10, the AC generator 12, and the AC motor 14 are arranged in series via a clutch 16, and in a state where the clutch 16 is off (open) (SHV mode and synchronous mode), SHHV is used. In the ON (closed) state (PHV mode), P
Each functions as an HV.

As shown in FIG. 1, the output shaft of the engine 10 is connected to the shaft of the generator 12 via a gearbox 18. The speed increaser 18 is a mechanism for increasing the rotation speed to a rotation speed region suitable for input to the generator 12. The output shaft of the motor 14 is connected to a speed reducer (or transmission) 2.
0, and is connected to a drive wheel 24 via a differential gear (differential) 22 or the like. A clutch 16 is provided between the generator 12 and the motor 14. The shaft of the generator 12 and the output shaft of the motor 14 are independent of each other when the clutch 16 is off, and are connected when the clutch 16 is on.

Further, the generator 12 and the motor 14 include:
Inverters 26 and 28 are provided correspondingly. The battery 30 receives the supply of charging power from the rotating machine (the generator 12 and / or the motor 14) functioning as a generator via the inverter 26 or 28, and the rotating machine (the generator 12 and / or the motor 14), discharge power is supplied via the inverter 26 or 28.

The ECU 32 controls the system shown in FIG. Therefore, the ECU 32 inputs an accelerator opening indicating a request for acceleration from a vehicle operator, a brake pedal force indicating a request for deceleration, an emblem switch state indicating an engine brake request, and the like. Further, the ECU 32 includes the generator 1
The rotation speed of the battery 30 is determined by the rotation speed sensor 34 by the rotation speed sensor 34 and the rotation speed of the motor 14 by the rotation speed sensor 36.
By the OC sensor 38, the voltage of the battery 30 is
0 indicates that each is detected. The ECU 32 determines whether to operate the generator 12 and the motor 14 as a generator or a motor, and
By controlling the switching operations of 6 and 28, the torque of the generator 12 and the motor 14 is controlled. Although the engine 10 is based on WOT operation, the ECU 32
The throttle opening of the engine 10 is controlled in a region where the efficiency is improved by operating the throttle opening. ECU32
Also, by controlling the opening of a linear valve 44 provided between the brake master cylinder 42 and a wheel cylinder (not shown), the ECU 32
Is controlled within the required braking force range.

(2) Mode Switching The first feature of this embodiment is that a synchronous mode is provided in addition to the SHV mode and the PHV mode. The synchronous mode here is executed when the mode is switched from the SHV mode to the PHV mode, and is a mode in which the rotation speed of the generator 12 gradually approaches the rotation speed of the motor 14. Field current of inverter 2
6 is realized by controlling the switching.
Specifically, the processing shown in FIG. 2 is executed.

FIG. 2 initially assumes that the system is operating in SHV mode. ECU32
In the SHV mode, the clutch 16 is turned off, and the inverter 26 is operated as regenerative means and the inverter 28 is operated as powering means. The mechanical output of the engine 10 is input to the generator 12 via the gearbox 18, and the output of the generator 12 is converted to DC by the inverter 26. At that time, the power output of the generator 12 and, consequently, the rotation speed of the engine 10 are controlled by the field current of the generator 12. DC power obtained from the inverter 26 is converted into AC by the inverter 28 and supplied to the motor 14. The output torque of the motor 14 is target-controlled to a required output torque Tttl determined by the accelerator opening, the brake depression force, and the state of the emblem switch by the switching control of the inverter 28 by the ECU 32. The difference between the power output of the generator 12 and the output of the motor 14 is covered by charging and discharging of the battery 30.

From this state, the vehicle speed V, that is, the motor 14
When it is detected based on the output of the rotation speed sensor 36 that the rotation speed of the motor has increased and reached the predetermined value V1, the ECU 32
Shifts the operation from the SHV mode to the synchronous mode. In the synchronous mode, the ECU 32 detects the rotation speeds of the generator 12 and the motor 14 by the rotation speed sensors 34 and 36, and
The field current of the generator 12 is gradually changed so that the error in the number of rotations becomes smaller. As a result of this control, the motor 14
When the vehicle speed V reaches a predetermined value V2 (V2> V1) after the error of the rotation speed of the generator 12 with respect to the rotation speed of the ECU 12 becomes substantially zero, the ECU 32 shifts the operation from the synchronous mode to the PHV mode. . That is, the clutch 16 is turned on. At this time, since the rotation speed of the generator 12 is substantially equal to the rotation speed of the motor 14, no shock is caused by turning on the clutch 16. In the synchronous mode, the required output torque Tttl is realized in the same manner as in the SHV mode.

In the PHV mode, since the clutch 16 is on, the mechanical output of the engine 10 is transmitted to the drive wheels 24 without being converted into electric power. ECU32
Supplements the excess or deficiency with respect to the required output torque by the generator 12 and the motor 14. That is, when the engine output is excessive with respect to the required output torque, the inverter 2
By operating the generators 6 and 28 as regenerative means, the generator 12 and the motor 14 are operated as generators, and the excess is converted into electric power and stored in the battery 30. Conversely, when the engine output is insufficient for the required output torque, the motor 1 is operated by operating the inverter 28 as powering means.
4 is operated as a motor, and the shortfall is covered by the discharge power of the battery 30.

In a state where the vehicle is traveling in the PHV mode, when it is detected based on the output of the rotation speed sensor 36 that the vehicle speed V has decreased and the vehicle speed V has become less than V1, the control proceeds to E.
The CU 32 switches from the PHV mode to the SHV mode. That is, the clutch 16 is turned off, and the inverter 26 is operated as regenerative means and the inverter 28 is operated as powering means.

As described above, in this embodiment, the SHV
When the mode is switched from the mode to the PHV mode, the process goes through the synchronous mode, so that the shock caused by turning on the clutch 16 does not occur. Further, since the rotation speed adjustment in the synchronous mode is realized by the field current control of the generator 12, components that cause mechanical loss such as CVT are not required. As a result, a high-efficiency PHV mode can be realized, and particularly high efficiency and low fuel consumption can be achieved during high-speed running. Furthermore, in the synchronous mode, the rotation speed of the generator 12 is gradually approaching the rotation speed of the motor 14. As a result, a change in the number of revolutions of the engine 10 is suppressed.
Emission deterioration is prevented. In addition, the clutch 16
The vehicle speed V2 for turning on and the vehicle speed V1 for turning off are different values (V1 <V2), so that the clutch 16 does not turn off even if the vehicle speed V rises or falls near V2. That is, frequent ON / OFF of the clutch 16 can be prevented.

(3) Torque distribution in PHV mode A second feature of the present embodiment is that the torque is distributed so that the total efficiency of the generator 12 and the motor 14 becomes the best when running in the PHV mode. is there. Normally, the generator 12 is only required to supply the average running power in the SHV mode, so that it is a small-rated generator. On the other hand, the motor 14 is required to be a large-rated motor because it is necessary to realize starting performance. Therefore, when the efficiency curves are drawn for each of the generator 12 and the motor 14, the characteristics are different from each other as shown in FIG. In the present embodiment, it is possible to always assist the engine 10 or absorb excessive torque with the best efficiency despite such differences in efficiency characteristics.

Therefore, in the present embodiment, a map in which the distribution ratio k is associated with the rotation speed and the torque is stored in the ECU 32 in advance as shown in FIG. When executing the PHV mode, the output of the rotation speed sensor 34 or 36, the required output torque Tttl and the engine output torque Te
The distribution ratio k is determined with reference to this map, using the difference Td of as a key. The ECU 32 calculates the required output torque Tt.
The difference Td between tl and the engine output torque Te is proportionally divided at a ratio of k: 1−k, and a portion corresponding to k is carried by the generator 12 and a portion corresponding to 1−k is carried by the motor 14. As can be understood by comparing and contrasting the efficiency characteristic shown in FIG. 3 with the map shown in FIG. 4, k becomes large in the low torque region where the generator 12 is more efficient. In the high torque region where the efficiency of the motor 14 is more efficient, k becomes smaller, so that the high efficiency region of the motor 14 can be used. Further, since the distribution ratio k is stored as a map, the operation of the ECU 32 becomes efficient.

(4) Prohibition of PHV Mode by SOC The third feature of this embodiment is that even if the vehicle is running at a high speed, if the SOC of the battery 30 is not within the target range, the PHV mode is prohibited.
The point is that the vehicle runs not in the SHV mode but in the SHV mode. That is, as shown in FIG. 5, when the SOC rises and leaves the target range of SL2 to SU2, the inhibition flag sflag is turned on accordingly. ECU
32 is SH while the prohibition flag sflag is on.
Execute the V mode. After that, the SOC recovers and SL1
When the value reaches the range of SU1, the prohibition flag sf is
The lag is turned off. The ECU 32 sets the prohibition flag sfl
When the ag is off, a mode is selected according to the speed V or the like.

Therefore, in this embodiment, even if the PHV mode continues for a long time, the prohibition flag sflag is turned on before the overcharge state or the overdischarge state of the battery 30 occurs, so that the SOC of the battery 30 can be appropriately managed. Life can be extended. Further, since SL1 to SU1 are set inside SL2 to SU2, a hysteresis relationship occurs between the change in the SOC of the battery 30 and the state of the prohibition flag sflag. Therefore, even if the SOC of the battery 30 rises or falls near SU2 or SL2, the problem that the prohibition flag sflag is repeatedly turned on and off frequently and the transition to the SHV mode is not repeated is eliminated.

(5) Operation of First Embodiment FIGS. 6 to 9 show the flow of the operation of the ECU 32 in the first embodiment.

The ECU 32 executes a predetermined initialization process in response to power-on or the like (100), and further drives the engine 10 (102). At this time, the ECU 32 performs the determination according to step 104. In step 104, the rotation speed sensor 36 is used as the rotation speed of the motor 14.
Whether the vehicle speed V detected by the vehicle is smaller than the predetermined value V0 and the vehicle can be regarded as stopped,
0 is equal to a predetermined value Vbm
It is determined whether overcharging can be considered as being larger than ax. If any of these conditions is satisfied, the ECU 32 executes a predetermined stop-time process (106). That is, the control target value of the throttle opening of the engine 10 is calculated to reduce the power output of the generator 12. After the stop processing, the operation of the ECU 32 proceeds to step 108 shown in FIG. Step 10
In step 8, the ECU 32 controls the throttle opening of the engine 10 in accordance with the control target value obtained in step 106, for example, to make the engine 10 idle. The ECU 32
Thereafter, until a key switch (not shown) is turned off (11
0), the above operation is repeated.

When it is determined in step 104 shown in FIG. 6 that the vehicle is not stopped and the battery 30 is not in an overcharged state, the ECU 32 determines a target acceleration torque T1 based on the accelerator opening and determines a target acceleration torque T1 based on the brake pedaling force. The target braking torque T2 is calculated. When the emblem switch is turned on, the emblem-equivalent regenerative torque T3 is also calculated. The ECU 32 calculates the total torque Tttl = T1 + T2 + of the target acceleration torque T1, the target braking torque T2, and the regenerative torque T3 equivalent to the emblem.
T3 is obtained (112). This total torque Tttl
Is the basis for determining the control target values of the torque of the generator 12, the torque of the motor 14, and the opening of the linear valve 44.

The following steps 114 to 120 are steps for executing the processing shown as the third feature of this embodiment, that is, the prohibition processing of the PHV mode according to the SOC. These steps are based on the prohibition flag sflag and S
The process is performed using the SOC of the battery 30 detected by the OC sensor 38.

In FIG. 6, first, the SOC of the battery 30 is
Step 114 is performed to determine whether or not has left the area from SL2 to SU2. If the determination condition in step 114 is satisfied, then in step 116, 1 is set to the prohibition flag sflag (prohibition flag on). Further, in step 118, the SOC
Is determined to be in an area equal to or greater than SL1 and less than SU1. If this determination is made, sflag is set to 0 in the subsequent step 120 (the prohibition flag is turned off).
However, the SOC is set to the on / off state of the inhibition flag sflag.
Since it is necessary to provide a hysteresis characteristic to the change, in step 114, sflag = 0 is added as a condition in addition to the above-described SOC condition, and in step 118, sflag is set to 1 as a condition. .

After the PHV mode prohibition processing in steps 114 to 120 is completed, step 1 shown in FIG.
Step 22 is executed. In step 122, it is determined whether the prohibition flag sflag is 1 and whether the vehicle speed V is less than a predetermined value V1. Prohibition flag sfl
If ag is 1, it is necessary to forcibly execute the SHV mode.
Move to 4. When the vehicle speed V is less than the predetermined value V1,
The operation of the ECU 32 proceeds to step 124 in order to execute the SHV mode according to FIG. If none of these conditions is satisfied, that is, sflag = 0 and V ≧ V
If it is 1, the operation of step 126 shown in FIG. 8 is executed.

In step 122, sflag = 1,
Alternatively, when it is determined that V <V1, in the following step 124, 1 is set to the variable mode indicating the driving mode.
Is set. When the variable mode is 1, the variable mode indicates the SHV mode, the variable mode 2 indicates the synchronous mode, and the variable mode 3 indicates the PHV mode. . After execution of step 124, the ECU 32 turns off the clutch 16 (12
8) The mechanical connection between the generator 12 and the motor 14 is disconnected.
As a result, the SPHV shown in FIG. 1 is in a state where it can travel as an SHHV.

The ECU 32 detects the SOC of the battery 30 using the SOC sensor 38, inputs an accelerator opening indicating the amount of depression of the accelerator pedal by the vehicle operator, and sets the target rotation speed of the engine 10 based on these amounts. An operation is performed (130). As the calculation method, the method described in Japanese Patent Application No. 6-184391 previously proposed by the present applicant can be used. However, when determining the target rotational speed of the engine 10, a change in the rotational speed is limited so that the emission of the engine 10 does not deteriorate.

The ECU 32 calculates the target value of the torque of the generator 12 (for example, the target value of the field current) so that the target rotation speed determined in this way is realized, and if necessary, the engine 10 The control target value of the throttle opening is calculated and determined (132).

The ECU 32 determines in a succeeding step 134 whether or not the total torque Tttl calculated in the above-described step 112 is a positive value. If the total torque Tttl is positive, it means that the vehicle should be accelerated, and if it is negative, it means that the vehicle should be decelerated. If it is determined that Tttl> 0,
The ECU 32 uses the total torque Tttl to
4 is compared with the maximum value Tmmax of the output torque, and the smaller one is selected (136). That is, the total output torque Tttl is limited by the maximum output torque Tmmax shown in FIG. 10, and the target output torque Tm of the motor 10 is determined.

Conversely, at step 134, Tttl ≦
If the ECU 32 determines that the total torque T
ttl is compared with the minimum output torque Tmmin of the motor 10, and the larger one is the target output torque T of the motor 10.
Select m. Accordingly, the target output torque Tm includes:
The restriction by the minimum output torque Tmmin shown in FIG. 10 is added. The ECU 32 further subtracts the restriction ΔTb by the battery voltage of the battery 30 from the control target value Tm determined in this way, and resets the obtained value to the target output torque Tm. The ECU 32 instructs the linear valve 44 to open the linear valve 44 in order to allocate a torque obtained by subtracting the target output torque Tm of the motor 10 from the total torque Tttl to the master cylinder 42, that is, the hydraulic brake (1).
40).

The ECU 32 determines in step 136 or 140
After the execution, the aforementioned step 108 is executed. That is, by controlling the switching operation of the inverter 28, the output torque of the motor 14 is controlled to the control target value Tm, and when necessary, a command regarding the throttle opening is given to the engine 10.

In step 122 described above, sflag
If none of the conditions of = 1 and V <V1 are satisfied, step 126 shown in FIG. 8 is executed. In step 126, first, the prohibition flag sf
It is determined whether or not lag is 0, whether or not the vehicle speed V is equal to or higher than the predetermined value V1, and whether or not the variable mode corresponds to one of 1 and 2. When all of these conditions are satisfied, the shift from the SHV mode to the PHV mode is not prohibited (sflag = 0), the vehicle speed V is sufficiently high (V ≧ V1), and the shift to the PHV mode is still being performed. State (mode = 1 or 2). Therefore, in this case, step 142 shown in FIG. 8 is executed, and the variable mode is set to 2 indicating the synchronous mode.

After executing step 142, the ECU 32 sets the target rotation speed of the generator 12 to the rotation speed of the motor 14 detected by the rotation speed sensor 36 (144). EC
U32 calculates the target output torque Tg of the generator 12 so that the control target value of the rotation speed determined in step 144 is realized (146).

The ECU 32 further determines that the vehicle speed V is equal to or higher than the predetermined value V2 shown in FIG. 2 (that is, the vehicle speed V is sufficiently high) and that the generator 1
The absolute value of the difference between the rotation speed of the motor 2 and the rotation speed of the motor 14 detected by the rotation speed sensor 36 is smaller than a predetermined minute value ΔN (the rotation speed of the generator 12 sufficiently matches the rotation speed of the motor 14). Is determined) (148). Unless both of these conditions are satisfied, the operation of the ECU 32 proceeds from step 148 to step 134 shown in FIG.
Move to That is, the target output torque Tg of the generator 12 determined in step 146 is output in step 108, and the output torque of the motor 14 is controlled based on the total torque Tttl determined in step 112.

If all of the conditions in step 148 are satisfied, it is considered that the condition for shifting to the PHV mode has been satisfied, so 3 is set to the variable mode (150). If the variable mode is set to 3 in step 150, the next time step 126 is executed, the determination condition of this step will not be satisfied, so that step 154 and subsequent steps shown in FIG.

Step 152 is a process in which the clutch 16 is turned on to mechanically connect the generator 12 and the shaft of the motor 14. After executing step 154, the ECU 32 calculates the output torque Te of the engine 10 based on the throttle opening and the like, and further subtracts the calculated output torque Te from the total torque Tttl to obtain the differential torque T.
d is calculated (156). When the differential torque Td thus obtained is positive, the engine 10 needs to be torque assisted by the generator 12 and the motor 14, and when negative, the excess torque of the engine 10 is reduced. It needs to be absorbed in the battery 30. Therefore, the ECU
32 determines whether or not the differential torque Td after execution of step 156 is positive;
Are executed, steps 162 to 166 are executed if the result is negative.

In step 160, the ECU 32
Sets the target output torque Tg of the generator 12 to 0 while the target output torque Tm of the motor 14
Set d. However, at that time, the maximum output torque Tmm
The smaller of the difference torque Td and the maximum output Tmmax is set as the target output torque Tm in order to add a limit by ax.

On the other hand, in step 162,
The distribution ratio k is calculated using FIG. 4 described above, that is, based on the rotational speed detected by the rotational speed sensor 34 or 36 and the differential torque Td. In step 164, the value obtained by multiplying the differential torque Td by the distribution ratio k
Is set to the target output torque Tg. However, also in this case, in order to add a limit by the minimum output torque Tgmin,
The larger of kTd and Tgmin is the target output torque T
g. Furthermore, the target output torque T of the motor 14
m is set to a value obtained by subtracting the target output torque Tg of the generator 12 from the difference torque Td. However, Td−Tg and Td are set so as to be restricted by the minimum output torque Tmmin.
The larger one of mmin is set to Tm. Further, ΔTb1 or ΔTb2 is subtracted from Tg and Tm, respectively, whereby a restriction by the voltage Vb of the battery 30 is added. In step 164, Tg is set to Tm.
The reason is determined earlier because Tgmin is smaller than Tmmin. Step 16 following step 164
In 6, the amount obtained by subtracting the total value Tm + Tg of the target output torques of the generator 12 and the motor 14 from the differential torque Tg is distributed to the hydraulic brake, and the opening degree is commanded to the linear valve 44 according to this distribution.

After execution of step 160 or 166, the ECU
The operation at 32 moves to step 108. Step 1
At 08, the target output torques Tg and Tm are output.
That is, the generator 12 and the motor 14 compensate for the excess or deficiency of the output Te of the engine 10 with respect to the total torque Tttl determined according to the accelerator opening and the like.

When the vehicle is running in the PHV mode in this manner, the SOC of the battery 30 falls within the target range (SL2).
It is assumed that the battery 30 has escaped from the above (SU1 and below) and the battery 30 has shown a tendency to overcharge or overdischarge. When this tendency appears,
Processing of steps 114 to 120 described above, especially step 1
By 16, the prohibition flag sflag is set to 1.
Then, since the determination condition of step 122 is satisfied, the operation after step 124, that is, the control operation according to the SHV mode is forcibly executed. As a result of the execution of the SHV mode running, the SOC of the battery 30 becomes SL1 or more and S
If it returns to the range below U1, steps 114 to 12
0, especially the prohibition flag sf
0 is set to lag. At this time, if the vehicle speed V is lower than V1, the traveling in the SHV mode is continued. However, if V ≧ V1, the conditions of steps 122 and 126 are satisfied, and the operation after step 142, that is, the synchronous mode Be executed. When the determination condition of step 148 is satisfied after the execution of the synchronous mode, the variable mode is set.
Is set to 3 (150), and the operation after step 154, that is, the PHV mode is executed.

The above-described functions and effects are realized by such a series of operations.

(6) Second Embodiment FIG. 11 shows a system configuration of an SPHV according to a second embodiment of the present invention. In this figure, only mechanical connection is shown for simplicity of illustration, but power wiring,
The signal wiring, the hydraulic piping and the like may be the same as those shown in FIG. The system configuration shown in this figure is a parallel SPHV. That is, the system configuration is such that the generator 12 side and the motor 14 side are connected in parallel as viewed from the engine 10 side by the mechanical connection member 46. With such a system configuration, the same operation and effect as those of the first embodiment can be obtained.

(7) Third and Fourth Embodiment FIG. 12 shows a part of the flow of the operation of the ECU 32 in the third embodiment of the present invention, and FIG. 13 shows the EC in the fourth embodiment.
A part of the operation flow of U32 is shown, respectively.
The operations shown in these figures are all part of the control operation in the PHV mode.

First, in the third embodiment shown in FIG. 12, when it is determined in step 158 that the differential torque Td is positive, the ECU 32 executes step 162 to determine the distribution ratio k. Once the distribution ratio k is determined,
The ECU 32 calculates the maximum output torques Tgmax and Tmma.
While limiting by x, kTd is set to the target output torque Tg of the generator, and Td-Tg is set to the target output torque Tm of the motor 14 (160a).

Conversely, if it is determined in step 158 that the differential torque Td is not positive, the ECU 32 executes step 164a without executing step 162. That is, the target output torques Tg and Tm of the generator 12 and the motor 14 are set to Td and 0, respectively.
However, the target output torque Tg of the generator 12 is limited by the minimum output torque Tgmin of the generator 12.
The ECU 32 executes step 166 after limiting the target output torques Tg and Tm by ΔTb1 and ΔTb2 described above. Step 160a or 166
After executing a, the ECU 32 proceeds to step 108.

As described above, in the above-described first embodiment, the motor 14 sometimes functions as a generator during the traveling in the PHV mode. On the other hand, in this embodiment, the motor 14 does not function as the generator. In the first embodiment, the generator 12 does not function as a motor, but in this embodiment, the generator 12 also functions as a motor in the PHV mode. With such a configuration, the same effect as that of the first embodiment can be obtained.

In the fourth embodiment shown in FIG.
Step 162 is performed prior to step 158, and the distribution ratio k is determined. If it is determined in step 158 that the differential torque Td is positive, step 160
If it is determined that a is not positive, steps 164 and 166 are executed, respectively. Therefore, in the fourth embodiment, the generator 12 and the motor 14 may both function as a generator and a motor. In this embodiment, the same effects as in the second and third embodiments can be obtained.

(8) Fifth Embodiment FIG. 14 shows a flow of the operation of the ECU 32, particularly a part of the operation in the SHV mode, according to a fifth embodiment of the present invention. In the process shown in this figure, once the SHV mode is started, this mode is forcibly continued for a predetermined time.

That is, in this embodiment, step 12
4 and the SHV mode is started, the mode 1 counter incorporated in the ECU 32 is turned on accordingly (168). Thereafter, the mode1 counter continuously performs counting. Once the mode1 counter is turned on, the operation of step 128 and thereafter is executed regardless of whether the condition of step 122 is satisfied (170). When the count value of the mode1 counter reaches a predetermined value (172), this counter is turned off (174).
Step 122 when the mode1 counter is turned off
If none of the determination conditions are satisfied, step 12
The operations after 6 are executed.

Therefore, in this embodiment, mode
Since the SHV mode is forcibly executed until one counter counts up, for example, the prohibition flag sfla
In the period from when g changes from 0 to 1 to 1 to 0, at least the time required for the mode1 counter to count up is secured. Therefore, in the present embodiment, it is possible to prevent frequent changes in the value of the prohibition flag sflag, and thus frequent switching between the PHV mode and the SHV mode, without giving the hysteresis characteristic as shown in FIG. it can. Accordingly, SO
SL1, SU1 and SL2, SU2 for C
Since there is no need to provide a set of thresholds, step 1
14 to 120 can be simplified.

[0060]

As described above, according to the present invention,
When the SOC of the battery is out of the first control target range, the forcible SHV running is performed. Therefore, even if the PHV running is continued for a long time, the SOC of the battery is maintained at a certain frequency.
Management is performed to prevent the battery from being overcharged or overdischarged.

Further, according to the present invention, when the SOC of the battery is restored to the second control target range included in the first control target range by the forced SHV driving, the forced SHV driving is terminated. In addition, the forcible SHV traveling is not repeatedly executed with the change of the SOC, and the frequent opening and closing of the connection opening and closing means is prevented.

According to the present invention, or by forced SHV
Since the forced SHV traveling is terminated after a predetermined time has elapsed from the start of the traveling, the forced SHV traveling is not frequently repeated with the change of the SOC, and frequent opening and closing of the connection opening / closing means is prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a system configuration according to a first embodiment of the present invention.

FIG. 2 is a timing chart showing a mode switching operation.

FIG. 3 is a diagram showing efficiency characteristics of a generator and a motor.

FIG. 4 is a diagram showing a distribution ratio map for a generator and a motor.

FIG. 5 is a timing chart showing on / off processing of a prohibition flag according to SOC.

FIG. 6 is a flowchart illustrating a flow of an operation of an ECU according to the first embodiment.

FIG. 7 is a flowchart illustrating a flow of an operation of the ECU according to the first embodiment.

FIG. 8 is a flowchart showing a flow of an operation of the ECU in the first embodiment.

FIG. 9 is a flowchart showing a flow of an operation of the ECU in the first embodiment.

FIG. 10 is a diagram showing output characteristics of a generator and a motor.

FIG. 11 is a block diagram showing a system configuration according to a second embodiment of the present invention.

FIG. 12 is a flowchart illustrating a flow of an operation of an ECU according to the third embodiment.

FIG. 13 is a flowchart illustrating a flow of an operation of an ECU according to a fourth embodiment.

FIG. 14 is a flowchart illustrating a flow of an operation of an ECU according to a fifth embodiment.

[Explanation of symbols]

Reference Signs List 10 engine 12 generator 14 motor 16 clutch 26, 28 inverter 30 battery 32 ECU 34, 36 rotation speed sensor 38 SOC sensor 40 voltage sensor V1, V2 threshold value related to vehicle speed k distribution ratio SL1, SU1, SL2, SU2 SOC Such determination threshold value T1 Target acceleration torque T2 Target braking torque T3 Emblem-equivalent regenerative torque Tttl Total torque sflag Prohibition flag mode Variable indicating mode Tm Target output torque of motor Tg Target output torque of generator Te Engine output torque Td Differential torque

Claims (3)

(57) [Claims] 1. An engine, a generator driven by a mechanical output of the engine, a battery charged by a power output of the generator, and a motor driven by a discharge output of the battery;
A series-parallel hybrid electric vehicle comprising: a connection opening / closing means for opening / closing a mechanical connection between a generator and a motor; wherein the mechanical connection between the generator and the motor is opened by the connection opening / closing means; Means for running the series-parallel electric vehicle in parallel while closing the mechanical connection between the generator and the motor by the connection opening / closing means, and using at least one of the generator and the motor for acceleration / deceleration. Means for running as a hybrid vehicle, and means for forcibly running the series-parallel hybrid electric vehicle as a series hybrid vehicle when the state of charge of the battery is outside the first control target range. Control device. 2. The control device according to claim 1, wherein the state of charge of the battery is included in the first control target range as a result of forcibly running the series-parallel hybrid electric vehicle as a series hybrid vehicle. A control device for terminating control for forcibly driving the series-parallel hybrid electric vehicle as a series hybrid vehicle when the value falls within the range. 3. The control device according to claim 1, wherein the series-parallel hybrid electric vehicle is forcibly driven after a lapse of a predetermined time after the series-parallel hybrid electric vehicle is forcibly started running as a series hybrid vehicle. A control device for terminating control for running as a car.