JP5799493B2 - Motor rotation speed control device for mode switching of hybrid vehicle - Google Patents

Description

The present invention can be driven by power from an electric motor other than the engine, and is an electric travel (EV) mode that travels only by power from the electric motor, and a hybrid that travels by power from both the engine and the electric motor. For a hybrid vehicle having a running (HEV) mode,
In particular, the present invention relates to a motor speed control device for mode switching at the time of mode switching of a hybrid vehicle so that motor speed control at the time of mode switching between the EV mode and the HEV mode can be appropriately performed even at a low temperature.

As such a hybrid vehicle, for example, the one described in Patent Document 1 is known.
In this hybrid vehicle, a first clutch capable of changing the transmission torque capacity is interposed between the engine and the electric motor, and a second clutch and automatic transmission capable of changing the transmission torque capacity are interposed between the electric motor and the drive wheel.
By stopping the engine, releasing the first clutch and engaging the second clutch, it is possible to select the electric travel (EV) mode using only the power from the electric motor, and both the first and second clutches are engaged. Thus, the hybrid running (HEV) mode by the power from the engine and the electric motor can be selected.

In such a hybrid vehicle, it is necessary to start the engine (when switching EV → HEV mode) and stop the engine (when switching HEV → EV mode) when switching between the former EV mode and the latter HEV mode.
When switching the mode with starting / stopping of the engine, in order to prevent engine start / stop shock, the mode switching is performed under the rotational speed control of the electric motor with the second clutch slipped.

JP 2010-030428 A

  When controlling the motor speed at the time of switching the mode, controlling the speed of the electric motor by operating the torque of the electric motor to achieve the target motor speed in relation to the slip engagement state of the second clutch. Become.

By the way, when the oil temperature of the automatic transmission is low and the oil temperature is low, the operating response of the second clutch is slow due to the high hydraulic oil viscosity, and when the power supply temperature of the electric motor is low, the power supply performance is lowered. The control performance of the electric motor deteriorates.
For this reason, at the time of the low temperature, there may be a timing difference between the torque capacity change of the second clutch by the control and the motor torque change of the electric motor by the control.

If the motor torque increase of the electric motor is too early with respect to the torque capacity change of the second clutch due to the timing shift, the input side rotational speed (motor rotational speed) of the second clutch will rise and the second clutch will Causing the problem of overheating,
Conversely, if the motor torque increase of the electric motor is too slow with respect to the change in torque capacity of the second clutch due to the above timing deviation, the input side rotation speed (motor rotation speed) of the second clutch is drawn and the engine stalls. The problem of reaching.

  The present invention sets the target motor rotational speed used when controlling the motor rotational speed at the time of mode switching between the electric traveling mode and the hybrid traveling mode so as not to cause the above-described problems at low temperatures. An object of the present invention is to propose a motor speed control device at the time of mode switching of a hybrid vehicle that has solved the problem.

For this purpose, the motor speed controller at the time of mode switching of the hybrid vehicle according to the present invention has the following configuration.
First, to explain the premise hybrid vehicle,
An engine and an electric motor are provided as a power source, a first clutch capable of changing the transmission torque capacity is interposed between the engine and the electric motor, and a second clutch capable of changing the transmission torque capacity between the electric motor and the driving wheel and an automatic motor. A transmission is interposed.

As the running mode, the electric running mode can be selected only by the power from the electric motor by stopping the engine, releasing the first clutch and fastening the second clutch, and the first clutch and the second clutch By fastening together, it is possible to select a hybrid travel mode based on power from the engine and the electric motor.
When switching between the electric travel mode and the hybrid travel mode, the second clutch is caused to slip from the fully engaged state due to a decrease in the transmission torque capacity by the transmission torque capacity control , and the electric motor is operated in the slip engagement state of the second clutch. The mode switching is performed by controlling the number of revolutions of the electric motor so that the number of revolutions becomes a predetermined target motor number of revolutions.

The mode switching motor rotation speed control device of the present invention is provided with transmission oil temperature detection means and low oil temperature target motor rotation speed setting means for such a hybrid vehicle,
When the hydraulic oil temperature of the automatic transmission detected by the former transmission oil temperature detection means is low and the oil temperature is lower than the set value, the latter target motor speed setting means for the low oil temperature is set between the electric drive mode and the hybrid drive mode. This is characterized in that the target motor rotational speed used for the rotational speed control of the electric motor during the mode switching is switched from the predetermined target motor rotational speed to the following target motor rotational speed for low oil temperature.
Even if the transfer torque capacity control response of the second clutch decreases due to the low oil temperature lower than the above set value, the target motor speed for low oil temperature will be under the reduced transfer torque capacity control response of the second clutch. The motor rotation speed is determined so that the change in the motor torque due to the rotation speed control of the electric motor is not synchronized with the change in the transmission torque capacity due to the control so that the input rotation speed of the automatic transmission does not change abnormally.

According to the above-described motor speed control device for mode switching of the hybrid vehicle according to the present invention,
When controlling the rotational speed of the electric motor during mode switching between the electric travel mode and the hybrid travel mode, even if the transmission torque capacity control response of the second clutch decreases due to the low oil temperature below the set value, the decreased first (2) The transmission torque capacity change due to the control under the clutch torque control response does not cause a change in the motor torque due to the rotation speed control of the electric motor, and the input side rotation speed of the automatic transmission does not change abnormally. Since the low oil temperature target motor speed determined as described above is used instead of the predetermined target motor speed, the following effects can be obtained.
In other words, since the operational response of the second clutch when a low oil temperature above a high hydraulic oil viscosity is low, the torque capacity change due to torque transfer capacity control of the second clutch in such a slow response under rotation of the electric motor The motor torque change due to the number control cannot be timed as when the oil temperature is high. Between the torque change due to the transfer torque capacity control of the second clutch and the motor torque change due to the rotation speed control of the electric motor While the timing shift occurs, the second clutch changes the input rotation speed abnormally, causing the second clutch to overheat or engine stall.
In the present invention, the above-described target oil speed for low oil temperature is used in place of the predetermined target motor speed, so that the change in the transfer torque capacity by the transfer torque capacity control of the second clutch and the electric The timing of the motor torque change due to the motor speed control can be compensated, and the second clutch does not change the input speed abnormally, and thus the above problem does not occur , and the electric motor is as intended. The rotational speed can be controlled.

1 is a schematic plan view illustrating a power train of a hybrid vehicle to which a motor speed control device for mode switching according to the present invention can be applied. FIG. 2 is a block diagram showing a control system for the power train shown in FIG. FIG. 3 is an explanatory diagram showing a state change related to a target travel mode of the hybrid vehicle shown in FIGS. 3 is a flowchart showing a learning control program for target motor rotation speed when switching between EV mode and HEV mode (WSC mode), which is executed by an integrated controller in the control system shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
<Hybrid vehicle to which the present invention is applicable>
FIG. 1 illustrates a power train of a hybrid vehicle to which the motor speed control device for mode switching of the present invention can be applied,
This hybrid vehicle is based on a front engine and rear wheel drive vehicle (rear wheel drive vehicle), and is a hybrid of this.
Reference numeral 1 denotes an engine as a first power source, and reference numeral 2 denotes a drive wheel (rear wheel).

In the hybrid vehicle power train shown in FIG. 1, the automatic transmission 3 is arranged in tandem at the rear of the engine 1 in the vehicle front-rear direction in the same manner as a normal rear wheel drive vehicle.
A motor / generator 5 is provided in combination with a shaft 4 that transmits rotation from the engine 1 (crankshaft 1a) to the input shaft 3a of the automatic transmission 3.
This motor / generator 5 is provided as a second power source.

The motor / generator 5 functions as an electric motor (electric motor) or as a generator (generator), and is disposed between the engine 1 and the automatic transmission 3.
The first clutch 6 can be inserted between the motor / generator 5 and the engine 1, more specifically, between the shaft 4 and the engine crankshaft 1a, and the engine 1 and the motor / generator 5 can be disconnected by the first clutch 6. To join.
Here, the first clutch 6 is capable of changing the transmission torque capacity continuously or stepwise, for example, by controlling the clutch hydraulic oil flow rate and the clutch hydraulic pressure with a proportional solenoid continuously or stepwise, for example, It is composed of a wet multi-plate clutch that can be changed.

A second clutch 7 is inserted between the motor / generator 5 and the driving wheel (rear wheel) 2, and the motor / generator 5 and the driving wheel (rear wheel) 2 are detachably coupled by the second clutch 7.
Similarly to the first clutch 6, the second clutch 7 can change the transmission torque capacity continuously or stepwise. For example, the proportional hydraulic solenoid controls the clutch hydraulic fluid flow rate and the clutch hydraulic pressure continuously or stepwise. And a wet multi-plate clutch whose transmission torque capacity can be changed.

The automatic transmission 3 may be any known one, and by selectively engaging or releasing a plurality of speed change friction elements (clutch, brake, etc.), a transmission system is obtained by a combination of engagement and release of these speed change friction elements. It is assumed that the road (speed stage) is determined.
Therefore, the automatic transmission 3 shifts the rotation from the input shaft 3a at a gear ratio corresponding to the selected shift speed and outputs it to the output shaft 3b.
This output rotation is distributed and transmitted to the left and right rear wheels 2 by the differential gear device 8 and used for traveling of the vehicle.
However, it goes without saying that the automatic transmission 3 is not limited to the stepped type as described above, and may be a continuously variable transmission.

By the way, in FIG. 1, a dedicated clutch friction element existing in the automatic transmission 3 is used instead of newly establishing a dedicated second clutch 7 for detachably coupling the motor / generator 5 and the drive wheel 2.
In this case, the second clutch 7 performs the above-described shift speed selection function (shift function) when engaged, so that the automatic transmission 3 is in a power transmission state, and in addition, the first clutch 6 is released and engaged, A mode selection function to be described later can be achieved, and a dedicated second clutch is unnecessary, which is very advantageous in terms of cost.

  However, a dedicated second clutch 7 may be newly provided. In this case, the second clutch 7 may be provided between the input shaft 3a of the automatic transmission 3 and the motor / generator shaft 4, or the automatic transmission 3 Provided between the output shaft 3b and the rear wheel drive system.

In the power train of the hybrid vehicle shown in FIG.
When electric driving (EV) mode used at low load and low vehicle speed including when starting from a stopped state is required,
The first clutch 6 is released, and the automatic transmission 3 is brought into a power transmission state by the engagement of the second clutch 7.
The second clutch 7 is a shift friction element to be engaged at the current shift stage among the shift friction elements in the automatic transmission 3, and is different for each selected shift stage.

When the motor / generator 5 is driven in this state, only the output rotation from the motor / generator 5 reaches the transmission input shaft 3a, and the automatic transmission 3 changes the rotation to the input shaft 3a to the selected shift speed. The speed is changed according to the speed and output from the transmission output shaft 3b.
The rotation from the transmission output shaft 3b then reaches the rear wheel 2 via the differential gear device 8, and the vehicle can be driven in the electric drive (EV) mode using only the motor / generator 5.

When hybrid driving (HEV) mode used for high speed driving or heavy load driving is required,
By engaging the second clutch 7, the first clutch 6 is also engaged while the automatic transmission 3 is kept in the corresponding gear selection state (power transmission state).
In this state, both the output rotation from the engine 1 and the output rotation from the motor / generator 5 reach the transmission input shaft 3a, and the automatic transmission 3 changes the rotation to the input shaft 3a to the selected shift speed. The speed is changed according to the speed and output from the transmission output shaft 3b.
The rotation from the transmission output shaft 3b then reaches the rear wheel 2 via the differential gear device 8, and the vehicle can be driven in a hybrid running (HEV) mode using both the engine 1 and the motor / generator 5.

During such HEV mode driving, when the engine 1 is operated with the optimum fuel efficiency, the energy becomes surplus,
By operating the motor / generator 5 as a generator with this surplus energy, surplus energy is converted into electric power,
By storing this generated power to be used for driving the motor of the motor / generator 5, the fuel consumption of the engine 1 can be improved.

The engine 1, the motor / generator 5, the first clutch 6, and the second clutch 7 constituting the power train of the hybrid vehicle shown in FIG. 1 are controlled by a system as shown in FIG.
The control system of FIG. 2 includes an integrated controller 20 that controls the operating point of the power train in an integrated manner.
The operating point of the power train is the target engine torque tTe, the target motor / generator torque tTm and the target motor / generator speed tNm, the target transmission torque capacity tTc1 of the first clutch 6, and the target transmission torque capacity of the second clutch 7. It is specified by tTc2.

In order to determine the operating point of the power train, the integrated controller 20
A signal from the engine rotation sensor 11 for detecting the engine speed Ne;
A signal from the motor / generator rotation sensor 12 for detecting the motor / generator rotation speed Nm;
A signal from a transmission oil temperature sensor 13 (corresponding to transmission oil temperature detection means) for detecting the hydraulic oil temperature Tempoil of the automatic transmission 3,
A signal from the output rotation sensor 14 that detects the transmission output rotation speed No,
A signal from an accelerator opening sensor 15 for detecting an accelerator pedal depression amount (accelerator opening APO) representing a required load on the vehicle;
A signal from a storage state sensor 16 for detecting a storage state SOC (carryable power) of the battery 9 that stores power for the motor / generator 5;
A signal from a motor power supply temperature sensor 17 (corresponding to a motor power supply temperature detection means) that detects the temperature Tempbat of the battery 9 is input.

  Among the sensors described above, the engine rotation sensor 11, the motor / generator rotation sensor 12, the input rotation sensor 13, and the output rotation sensor 14 can be arranged as shown in FIG.

The integrated controller 20 includes the accelerator opening APO, the battery storage state SOC, and the transmission output speed No (vehicle speed VSP) among the above input information.
While selecting the driving mode (EV mode, HEV mode) that can realize the driving force of the vehicle desired by the driver,
Target engine torque tTe, target motor / generator torque tTm, target motor / generator rotation speed tNm, target first clutch transmission torque capacity tTc1, and target second clutch transmission torque capacity tTc2 are calculated.

  The target engine torque tTe is supplied to the engine controller 21, and the target motor / generator torque tTm and the target motor / generator rotation speed tNm are supplied to the motor / generator controller 22.

The engine controller 21 controls the engine 1 so that the engine torque Te becomes the target engine torque tTe.
The motor / generator controller 22 controls the motor / generator 5 via the battery 9 and the inverter 10 so that the torque Tm and the rotational speed Nm of the motor / generator 5 become the target motor / generator torque tTm and the target motor / generator rotational speed tNm. To do.

  The integrated controller 20 supplies a solenoid current corresponding to the target first clutch transmission torque capacity tTc1 and the target second clutch transmission torque capacity tTc2 to an engagement control solenoid (not shown) of the first clutch 6 and the second clutch 7, The first clutch 6 and the first clutch 6 so that the transmission torque capacity Tc1 of the first clutch 6 matches the target transmission torque capacity tTc1, and the transmission torque capacity Tc2 of the second clutch 7 matches the target second clutch transmission torque capacity tTc2. The second clutch 7 is individually controlled for engaging force.

<Mode switching control>
The integrated controller 20 determines the target drive torque obtained using the planned target drive force map from the transmission output speed No (vehicle speed) and the accelerator opening APO (braking operation force during braking), the battery storage rate SOC, Based on the vehicle operation state such as the accelerator opening APO and the transmission output rotational speed No (vehicle speed), the target travel mode is calculated based on the planned target operation mode region map.
As shown in FIG. 3, in addition to the electric travel (EV) mode and the hybrid travel (HEV) mode described above, the travel mode is a transition period between the electric travel (EV) mode and the hybrid travel (HEV) mode. Set the transient running (WSC) mode.

  In the electric travel (EV) mode, as shown in FIG. 3 and as described above, the engine 1 is kept stopped, the first clutch 6 (CL1) is released, and the second clutch 7 (CL2) is engaged. Alternatively, the automatic transmission 3 is set to the corresponding gear selection state (power transmission state) by slip engagement, and only the output rotation from the motor / generator 5 is transmitted to the rear wheel 2 under the shift by the automatic transmission 3.

  In the hybrid travel (HEV) mode, as shown in FIG. 3 and as described above, the second transmission 7 (CL2) is engaged and the automatic transmission 3 remains in the corresponding gear selection state (power transmission state) while the second clutch 7 (CL2) is engaged. 1 Clutch 6 (CL1) is also engaged, and both the output rotation from the activated engine 1 and the output rotation from the torque controlled motor / generator 5 are transmitted to the rear wheel 2 under the shift by the automatic transmission 3. To do.

When switching the mode from the hybrid driving (HEV) mode to the electric driving (EV) mode, as shown in FIG. 3 as the transient driving (WSC) mode, the second clutch 7 (CL2) is changed from the fully engaged state to the slip engaged state, Switching to the electric travel (EV) mode is completed by releasing the first clutch 6 (CL1) and stopping the activated engine 1 while controlling the rotational speed of the motor / generator 5.
At this time, since the second clutch 7 (CL2) is in the slip engagement state, the mode switching shock can be absorbed here to take a countermeasure against the shock.

When switching from electric drive (EV) mode to hybrid drive (HEV) mode, automatic transmission 3 is supported by slip engagement of second clutch 7 (CL2), as shown in Fig. 3 as transient drive (WSC) mode. While maintaining the gear selection state (power transmission state), the engine 1 in the stopped state is cranked and started by the engagement progression control of the first clutch 6 (CL1) and the rotation speed control of the motor / generator 5, and the engine 1 And switch to hybrid running (HEV) mode.
At this time, since the second clutch 7 (CL2) is in the slip engagement state, the engine start shock can be absorbed here to take a countermeasure against the shock.

When switching from EV to HEV mode with such engine start, in order to start the engine 1 by engaging the first clutch 6 (CL1) with the second clutch in the slip engagement state as described above for preventing the engine start shock,
After the engine 1 is started by starting the engine, the second clutch 7 (CL2) needs to be completely engaged from the slip engagement state.

  Thus, when the second clutch 7 (CL2) is completely engaged from the slip engagement state, the transmission output rotational speed No (vehicle speed) becomes higher than the HEV transition permitted vehicle speed during the transient running (WSC) mode, and the second When the slip rotation | Nm− (No × gear ratio) | of the clutch 7 (CL2) becomes equal to or less than the HEV transition permission slip rotation, the control for completely engaging the second clutch 7 (CL2) from the slip engagement state is started.

<Motor rotation speed control during mode switching>
The integrated controller 20 shows the target motor rotational speed tNm (target transmission input rotational speed) used for controlling the rotational speed of the motor / generator 5 when the mode is switched between the EV mode and the HEV mode (WSC mode) as shown in FIG. Based on the control program shown, learning control is performed as follows to contribute to motor rotation speed control at the time of mode switching (in WSC mode).

  In step S11, whether or not the transmission hydraulic oil temperature (ATF temperature) Tempoil is equal to or higher than the set temperature, that is, the operation response of the second clutch 7 (CL2) is not delayed. It is checked whether or not the oil temperature is in a high oil temperature range in which there is no timing difference between the change in torque capacity of CL2) and the change in motor torque of the motor / generator 5 due to control.

  In step S12, whether or not the power supply temperature (battery temperature) Tempbat of the motor / generator 5 is equal to or higher than the set temperature, that is, the control performance of the motor / generator 5 is deteriorated due to the deterioration of the performance of the battery 9, It is checked whether or not the power supply is in a high temperature range that does not cause a timing difference between the torque capacity change of the clutch 7 (CL2) and the motor torque change of the motor / generator 5 due to control.

While it is determined in step S11 that the transmission hydraulic oil temperature (ATF temperature) Tempoil is equal to or higher than the set temperature, and in step S12, the motor power supply temperature (battery temperature) Tempbat is determined to be equal to or higher than the set temperature,
Since there is no timing difference between the torque capacity change of the second clutch 7 (CL2) due to the control and the motor torque change of the motor / generator 5 due to the control, that is,
The motor torque of the motor / generator 5 increases too quickly with respect to the torque capacity change of the second clutch 7, and the second clutch 7 overheats due to the increase in the input side rotational speed (motor rotational speed) of the second clutch 7. No problem,
The motor torque of the motor / generator 5 increases too slowly with respect to the torque capacity change of the second clutch 7, and the problem of engine stall due to the input side rotation speed (motor rotation speed) of the second clutch 7 does not occur. Therefore, control proceeds to step S13.

In step S13, it is checked whether the mode is other than the transition mode (WSC mode) between the EV mode and the HEV mode.
While it is determined in step S13 that the EV mode or HEV mode is other than the WSC mode, in step S14, the normal accelerator operation fee is set as the target motor rotational speed tNm used in the rotational speed control of the motor / generator 5 in the WSC mode. Set the ring-oriented target motor speed in the WSC motor speed control map (Map), and in response to this, determine the HEV transition permission vehicle speed (EV → HEV mode switching complete and slip the second clutch 7) The vehicle speed (completely fastened from the state) is also set as usual.

  When it is determined that the temperature is still high in step S11 and step S12 and the WSC mode is determined in step S13, the target motor speed for WSC mode and the HEV transition permission vehicle speed are set in step S14 by ending the control as it is. Therefore, based on the target motor speed for WSC mode and the HEV transition permitted vehicle speed set in step S14, the motor / generator 5 speed control is performed and the second clutch 7 EV → HEV mode switching completion engagement control is performed. Do.

  However, while it is determined in step S11 that the transmission hydraulic oil temperature (ATF temperature) Tempoil is lower than the set temperature, the torque capacity change of the second clutch 7 is delayed with respect to the same control input, and the engine rotates with respect to this torque capacity change. The motor torque of the motor / generator 5 during the number control may change too quickly, and the second clutch 7 may be overheated due to an abnormal increase in the input side rotational speed (motor rotational speed). There is a problem that the engine stalls due to the pull-in (abnormal decrease) of the rotation speed (motor rotation speed).

In order to solve this problem, in this embodiment, when it is determined in step S11 that the transmission hydraulic oil temperature (ATF temperature) Tempoil is lower than the set temperature, in step S15, the transition mode (WSC) between the EV mode and the HEV mode is determined. In step S16, the target motor rotational speed tNm used for controlling the rotational speed of the motor / generator 5 in the WSC mode is set as normal while determining whether the EV mode or HEV mode is other than the WSC mode. Instead of the target motor speed with emphasis on accelerator operation feeling, the target motor speed for low oil temperature is set in the WSC motor speed control map (Map), and in response to this, the HEV transition permission vehicle speed ( The vehicle speed at which the second clutch 7 is completely engaged from the slip state when it is determined that the EV → HEV mode switching has been completed is also set for the low oil temperature learning.
Accordingly, step S16 corresponds to the low oil temperature target motor speed setting means in the present invention.

Here, the target motor speed for the low oil temperature is low, even if the torque capacity change of the second clutch 7 becomes slow due to the low oil temperature, The target motor speed is set so that the torque change does not cause a time-dependent change in the input side speed of the second clutch 7.
In addition, the HEV shift permission vehicle speed for the low oil temperature described above is fully engaged at the right timing as a countermeasure against the shock even if the torque capacity change of the second clutch 7 becomes slow due to the low oil temperature. Determine the vehicle speed.

  When it is determined that the oil temperature is still high in step S11 and the WSC mode is determined in step S15, the control is terminated as it is, so that the target motor speed for low oil temperature WSC mode and HEV at low oil temperature in step S16 Without setting the transition-permitted vehicle speed, the motor / generator 5 is controlled based on the low-oil-temperature WSC mode target motor rotational speed and the low-oil-temperature HEV transition-permitted vehicle speed learned in step S16. The engagement control for completing the EV → HEV mode switching of the second clutch 7 is performed.

  Note that the learning of the target motor speed for the low oil temperature WSC mode and the HEV transition permitted vehicle speed at the low oil temperature in step S16 is performed during the EV mode or HEV mode other than the WSC mode in step S15. The reason for this is that in WSC mode, motor torque fluctuates and accurate learning cannot be expected.

Even if it is determined in step S11 that the transmission hydraulic oil temperature (ATF temperature) Tempoil is equal to or higher than the set temperature, if it is determined in step S12 that the battery temperature Tempbat is lower than the set temperature, then in step S17, between the EV mode and the HEV mode. While checking whether the mode is other than the transition mode (WSC mode) and determining the EV mode or HEV mode other than the WSC mode, in step S18, the target motor rotational speed used in the rotational speed control of the motor / generator 5 in the WSC mode tNm is set in the WSC motor rotation speed control map (Map) in place of the normal motor rotation speed for emphasis on accelerator operation feeling, instead of the target motor rotation speed for battery low temperature. Allowed vehicle speed (vehicle speed at which the second clutch 7 is completely engaged from the slip state when it is judged that the EV → HEV mode switching has been completed) is also set for learning when the battery is cold and learning To do.
Accordingly, step S18 corresponds to the power source low temperature target motor rotation speed setting means in the present invention.

Here, the target motor speed for the low temperature of the battery described above is adjusted even when the speed control performance of the motor / generator 5 is lowered due to the low temperature of the battery, and the torque capacity change of the second clutch 7 is timed to the motor torque change. Thus, the target motor rotational speed is set so as not to cause an abnormal input side rotational speed change of the second clutch 7.
In addition, the HEV transition permission vehicle speed for the low temperature battery described above is the perfect engagement timing of the second clutch 7 for a shock countermeasure even if the rotational speed control performance of the motor / generator 5 is reduced due to the low battery temperature. The vehicle speed is set to a certain level.

  When it is determined in step S12 that the battery temperature Tempbat is lower than the set temperature and in step S17 the WSC mode is determined, the control is terminated as it is, so that the target motor speed for the WSC mode when the battery is low and the battery low temperature in step S18. The motor / generator 5 speed control is performed based on the battery low temperature WSC mode target motor speed and the battery low temperature HEV transition permission vehicle speed learned in step S18 without setting the HEV transition permission vehicle speed. The engagement control for completing the EV → HEV mode switching of the second clutch 7 is performed.

  Note that the learning of the target motor speed for WSC mode at low battery temperature and the HEV transition-permitted vehicle speed at low battery temperature in step S18 is performed during the EV mode or HEV mode other than WSC mode in step S17. The reason is that in WSC mode, the motor torque fluctuates and accurate learning cannot be expected.

<Effect of Example>
According to the motor speed control device at the time of mode switching of the hybrid vehicle according to the embodiment described above,
When the oil temperature of the transmission (ATF temperature) Tempoil is lower than the set temperature (step S11), the motor / generator 5 rotates in the WSC mode while in the EV mode or HEV mode (step S15). As the target motor rotation number used in the number control, instead of the above-mentioned target motor rotation number with emphasis on the usual accelerator operation feeling, the target motor rotation number for low oil temperature is set in the WSC motor rotation number control map (Map), In response to such switching of the target motor speed, the HEV transition permission vehicle speed (the vehicle speed at which the second clutch 7 is completely engaged from the slip state when it is determined that the EV → HEV mode switching has been completed) is also set to that for the low oil temperature. Learn (step S16)
While in the WSC mode (step S15), based on the low oil temperature WSC mode target motor speed and the low oil temperature HEV transition permitted vehicle speed learned in step S16, the motor / generator 5 speed control is performed. Since the engagement control for completing the EV → HEV mode switching of the two-clutch 7 is performed, the following effects can be obtained.

  In other words, when the oil temperature is low, the torque capacity change of the second clutch 7 is delayed for the same control input, and the motor torque change of the motor / generator 5 during the rotational speed control is too early for this torque capacity change. There arises a problem that the second clutch 7 becomes overheated due to the rising of the input side rotational speed (motor rotational speed) or the engine stalls due to the drawing of the input side rotational speed (motor rotational speed).

However, in the present embodiment, such a case, since thereby performing rotational speed control of the motor / generator 5 based on the target motor rotational speed for the WSC mode when as low oil temperature of above and for WSC mode when the oil temperature is low Coupled with the target motor speed being the set value as described above,
Even if the torque capacity change of the second clutch 7 becomes slow due to the low oil temperature, it becomes possible to adjust the motor torque change of the motor / generator 5 during the rotation speed control to this torque capacity change. It is possible to solve the problem that the engine 7 becomes overheated due to the rising of the input side rotational speed (motor rotational speed) or the engine stalls due to the input side rotational speed (motor rotational speed) being pulled.

In addition, at the time of the above low oil temperature, in order to perform the engagement control for completing the EV → HEV mode switching of the second clutch 7 based on the HEV transition permitted vehicle speed at the time of the low oil temperature,
Even if the torque capacity change of the second clutch 7 becomes slow due to the low oil temperature, it can compensate that the second clutch 7 is completely engaged at just the right timing for shock countermeasures. The occurrence of a mode switching shock can be prevented, and the durability and engine stall resistance of the second clutch 7 can be improved.

On the other hand, when the battery temperature Tempbat is lower than the set temperature (step S12), the target motor used for controlling the rotational speed of the motor / generator 5 in the WSC mode during the EV mode or HEV mode (step S17). As the rotation speed, instead of the above-mentioned target motor rotation speed with emphasis on the normal accelerator operation feeling, the target motor rotation speed for battery low temperature is set in the WSC motor rotation speed control map (Map), and switching of the target motor rotation speed is performed. In response to this, the HEV transition permission vehicle speed (the vehicle speed at which the second clutch 7 is completely engaged from the slip state when it is determined that the EV → HEV mode switching has been completed) is also set and learned for the battery low temperature (step S18),
While in the WSC mode (step S17), the motor / generator 5 speed control and the second clutch are performed based on the target motor speed for the WSC mode at low battery temperature and the HEV transition permitted vehicle speed at low battery temperature learned in step S18. Since the 7 EV → HEV mode switching completion fastening control is performed, the following effects can be obtained.

  That is, when the battery is at a low temperature, the control performance of the motor / generator 5 is reduced, and the torque capacity change of the second clutch 7 is not timed with respect to the motor torque change of the motor / generator 5 during the rotation speed control. There arises a problem that the clutch 7 is overheated due to the rising of the input side rotational speed (motor rotational speed), or the engine stalls due to the drawing of the input side rotational speed (motor rotational speed).

However, in the present embodiment, such a case, since thereby performing rotational speed control of the motor / generator 5 based on the street target motor rotational speed battery low temperature WSC mode described above, also target motor battery low temperatures WSC mode coupled also be rotational speed is set value as described above,
Even if the control performance of the motor / generator 5 deteriorates due to the low temperature of the battery, it is possible to time the motor torque change of the motor / generator 5 during the rotational speed control to the torque capacity change of the second clutch 7. It is possible to solve the problem that the two-clutch 7 is overheated due to the rising of the input side rotational speed (motor rotational speed), or the engine stalls due to the input side rotational speed (motor rotational speed) being pulled.

In addition, when the battery temperature is low, in order to perform the engagement control for completing the EV → HEV mode switching of the second clutch 7 based on the vehicle speed at which the HEV transition is permitted when the battery temperature is low,
Even if the control performance of the motor / generator 5 decreases due to low battery temperature, it is possible to compensate that the complete engagement timing of the second clutch 7 is performed at just the right timing for shock countermeasures. The occurrence of switching shock can be prevented, and the durability and engine stall resistance of the second clutch 7 can be improved.

Note that the switching to the target motor speed for the WSC mode at the low oil temperature and the HEV transition permitted vehicle speed at the low oil temperature in step S16 is performed while the EV mode or HEV mode other than the WSC mode is determined in step S15. ,
In addition, the switching to the target motor speed for the WSC mode at the time of low battery temperature and the HEV transition permission vehicle speed at the time of low battery temperature is performed in step S18 while the EV mode or HEV mode other than the WSC mode is determined in step S17. Because
The switching can be performed during the WSC mode in which the motor torque fluctuation is severe , so that it is possible to avoid the adverse effect that the above effects cannot be obtained as predetermined, and the following effects can also be obtained.

In other words, if the above learning of the target motor speed and HEV transition-permitted vehicle speed is performed in WSC mode, this learning result is immediately reflected during motor speed control in WSC mode, which is a factor unrelated to driving operation. The driver has a sense of incongruity due to changes in the target motor speed and HEV transition permission vehicle speed based on
In this embodiment, the learning of the target motor speed and the HEV transition permission vehicle speed is performed in advance in the EV mode or HEV mode other than the WSC mode, so that the driver does not feel uncomfortable as described above.

1 Engine (Power source)
2 Drive wheels (rear wheels)
3 Automatic transmission 4 Motor / generator shaft 5 Motor / generator (power source: electric motor)
6 First clutch 7 Second clutch 8 Differential gear unit 9 Battery (motor power supply)
10 Inverter
11 Engine rotation sensor
12 Motor / generator rotation sensor
13 Transmission oil temperature sensor (Transmission oil temperature detection means)
14 Transmission output rotation sensor
15 Accelerator position sensor
16 Battery charge sensor
17 Battery temperature sensor (Motor power supply temperature detection means)
20 Integrated controller
21 Engine controller
22 Motor / generator controller

Claims (4)

An engine and an electric motor are provided as a power source, a first clutch capable of changing the transmission torque capacity is interposed between the engine and the electric motor, and a second clutch capable of changing the transmission torque capacity between the electric motor and the driving wheel and an automatic motor. Through the transmission,
By stopping the engine, releasing the first clutch and engaging the second clutch, it is possible to select an electric travel mode based only on the power from the electric motor, and by engaging both the first clutch and the second clutch, the engine and Hybrid driving mode with power from the electric motor can be selected, the second clutch slips from the fully engaged state due to the decrease in the transmission torque capacity by the transmission torque capacity control , and the rotation speed of the electric motor in the slip engagement state of the second clutch In a hybrid vehicle in which the mode is switched between the electric travel mode and the hybrid travel mode by controlling the number of revolutions of the electric motor that makes the predetermined target motor revolution number,
Transmission oil temperature detection means for detecting the hydraulic oil temperature of the automatic transmission;
When the transmission oil temperature detected by the means is lower than the set value, the low oil temperature lower than the set value is used for controlling the rotational speed of the electric motor during mode switching between the electric drive mode and the hybrid drive mode. Even if the transmission torque capacity control response of the second clutch decreases, the motor torque by the rotational speed control of the electric motor changes to the transmission torque capacity change by the control under the reduced transmission torque capacity control response of the second clutch. A low oil temperature target motor rotational speed determined so that the change is timed and the input-side rotational speed of the automatic transmission does not change abnormally is used instead of the predetermined target motor rotational speed. And a motor speed control device for mode switching at the time of mode switching of the hybrid vehicle, comprising: a target oil speed setting means for low oil temperature. In the hybrid vehicle mode switching motor rotation speed control device according to claim 1,
Motor power supply temperature detection means for detecting the power supply temperature of the electric motor;
When the power source temperature detected by the means is lower than the set value, the electric motor is controlled at the low speed of the electric motor during the mode switching between the electric travel mode and the hybrid travel mode. also decreases the rotational speed control performance of the motor, the motor torque changes due to the rotation speed control of the electric motor in the rotational speed control performance under the beat low, the transmission torque capacity change due to torque transfer capacity control of the second clutch A power source that uses a target low-temperature target motor rotational speed determined so that the input-side rotational speed of the automatic transmission does not change abnormally in place of the predetermined target motor rotational speed. A motor speed control device for mode switching at the time of mode switching of a hybrid vehicle, comprising: a target motor speed setting means for low temperature use. Mode switching from the electric drive mode with the starting of the engine to the hybrid travel mode, the start of the second said engine by fastening and speed control of the electric motor of the first clutch in a state in which the clutch is slip-engaged 3. The motor for switching the mode of the hybrid vehicle according to claim 1 or 2, wherein the motor is performed by completely engaging the second clutch from the slip engagement state when the vehicle speed exceeds a predetermined vehicle speed after the engine is started. In the rotation speed control device,
In response to switching from the predetermined target motor rotational speed to the low oil temperature target motor rotational speed and / or the low power source temperature target motor rotational speed, the mode switching from the electric travel mode to the hybrid travel mode is performed. 2 Correcting the full engagement region of the second clutch, correcting the predetermined vehicle speed for determining whether or not to fully engage the clutch from the slip engagement state, and correcting the complete engagement region of the second clutch determined by the predetermined vehicle speed A motor rotation speed control device for mode switching of a hybrid vehicle, characterized in that means is provided. In the motor speed control device at the time of mode switching of the hybrid vehicle according to any one of claims 1 to 3,
Switching from the predetermined target motor rotational speed to the low oil temperature target motor rotational speed and / or the power source low temperature target motor rotational speed is a mode switching state between the electric travel mode and the hybrid travel mode. In the previous mode, it is determined in advance whether the low oil temperature state and / or the power low temperature state from the transmission oil temperature detection value and / or the power supply temperature detection value, and the low oil temperature state and / or A motor rotation speed control device for mode switching of a hybrid vehicle, which is performed in response to determination of a power supply low temperature state.

Images