JP5088058B2 - Hybrid vehicle mode switching control device - Google Patents

Description

The present invention can be driven not only by the engine but also by power from the motor / generator, and by electric power (EV) mode in which the vehicle travels only by power from the motor / generator, and by power from both the engine and the motor / generator. Hysteresis in the determination value of the accelerator opening for determining the mode switching between the electric driving (EV) mode and the hybrid driving (HEV) mode, particularly for a hybrid vehicle having a hybrid driving (HEV) mode capable of driving The present invention relates to a mode switching control device for a hybrid vehicle provided with.

As a mode switching control device for a hybrid vehicle used in the hybrid vehicle as described above, a device as described in Patent Document 1 is conventionally known.
This hybrid vehicle mode switching control device includes an engine and a motor / generator (electric motor) as power sources, an electric travel mode (EV mode, electric motor mode) which is a travel mode using only the motor / generator, and the engine and motor / generator. It is assumed that a hybrid driving mode (HEV mode, combined mode), which is a driving mode in which is used together, is selected.

In the electric travel mode, when the accelerator opening increases and becomes larger than the EV mode → HEV mode change determination value, the mode is switched to the hybrid travel mode. On the other hand, in the hybrid travel mode, when the accelerator opening decreases and falls below the determination value for changing the HEV mode to the EV mode, the mode is switched to the electric travel mode.
Here, in order to prevent the hunting phenomenon that frequently occurs between the two modes, the EV mode → HEV mode change judgment value is set to a larger value than the HEV mode → EV mode change judgment value, Hysteresis is provided between these change determination values.
JP-A-6-48190

  However, in the mode switching control device described in Patent Document 1, the EV mode → HEV mode change determination value and the HEV mode → EV mode change determination value are constant values, and the hysteresis between these change determination values. Since the size of the vehicle is constant regardless of the vehicle speed, the following problems occur.

In other words, when the above hysteresis is set to a small value, when driving at a relatively low speed in an urban area or the like, the vehicle tends to travel while greatly changing the accelerator opening. Therefore, there is a problem that the transition from the EV mode to the HEV mode with the engine start and the transition from the HEV mode to the EV mode with the engine stop frequently occurs, resulting in deterioration of fuel consumption and drivability. Arise.

On the other hand, when the above hysteresis is set to a large value, it tends to travel while slightly changing the accelerator opening when traveling at a relatively high speed in a suburb or highway.
When this small accelerator opening change stays within the large hysteresis region, and does not lead to a mode switching command, and the motor / generator torque and battery storage status (carryable power) can be EV driven. Nevertheless, the HEV mode is continuously selected without issuing a command to switch to the EV mode, and there is a problem that the fuel efficiency improvement effect that is a characteristic of the hybrid vehicle cannot be enjoyed.

In addition, the electric clutch control system including the motor / generator and the inverter rises in temperature due to a heavy load, and the second clutch is controlled mainly by slip control for shock countermeasures when starting the engine. In spite of the rise in the temperature of the automatic transmission (the temperature of the automatic transmission because it operates with the hydraulic oil of the automatic transmission)
There is a strong tendency to select the EV mode that imposes a heavy load on the electric travel control system, and frequent switching between the EV mode and the HEV mode that frequently causes engine start (slip control of the second clutch) occurs. Problems such as damage to the electric travel control system and accelerated deterioration of the second clutch and its hydraulic oil also occur.

The present invention proposes a mode switching control device for a hybrid vehicle that solves the above problem by making the hysteresis not constant as in the prior art and changing the hysteresis so as to avoid the above problem. Objective.

For this purpose, the mode switching control device for a hybrid vehicle according to the present invention has the following configuration described in claim 1.
First, a hybrid vehicle as a premise will be described. This includes an engine and a motor / generator as a power source, the engine is stopped, and an electric travel mode using only the power from the motor / generator, and the engine and motor / generator The hybrid travel mode based on power from both sides is selected and switched based on at least the accelerator opening.

The present invention relates to such a hybrid vehicle,
The accelerator opening hysteresis between the mode switching condition from the electric driving mode to the hybrid driving mode and the switching condition from the hybrid driving mode to the electric driving mode is changed according to the driving state and driving environment of the vehicle. and,
It is characterized in that the hysteresis of the accelerator opening is increased as the vehicle speed is the vehicle driving state and the driving environment, and the vehicle speed is lower .

According to the above-described hybrid vehicle mode switching control device according to the present invention,
When the mode switching condition is satisfied, the mode is switched from the electric travel mode to the hybrid travel mode, and conversely, the hybrid travel mode is switched to the electric travel mode.
When this mode is switched, the hysteresis of the accelerator opening between the mode switching condition from the electric driving mode to the hybrid driving mode and the switching condition from the hybrid driving mode to the electric driving mode depends on the driving state and driving environment of the vehicle. Change. Thereby, the following effects can be obtained.

That is, for example, when the vehicle is traveling at a relatively low speed in an urban area or the like and tends to travel while greatly changing the accelerator opening, the hysteresis of the accelerator opening is set large. As a result, in response to the large accelerator opening change, the transition from the electric travel mode to the hybrid travel mode with engine start or the transition from the hybrid travel mode to the electric travel mode with engine stop frequently occurs. It is possible to prevent the occurrence. As a result, it is possible to avoid problems related to the deterioration of fuel consumption and the deterioration of drivability due to the frequent mode switching.

Further, for example, when the vehicle is traveling at a relatively high speed in a suburb or an expressway and the vehicle tends to travel while slightly changing the accelerator opening, the hysteresis of the accelerator opening is set small. This makes it possible to cause mode switching even with the small accelerator opening change. As a result, when the motor / generator torque and battery storage state (carryable power) are those that allow electric travel, the switch to the electric travel mode is surely performed to improve fuel efficiency, which is a characteristic of hybrid vehicles. You can enjoy the effect.

Further, the hysteresis of the accelerator opening can be changed not only according to the vehicle speed condition (vehicle driving state) as described above but also according to the traveling environment. For example, when the electric travel control system including a motor / generator rises in temperature due to a large load as the travel environment, the above accelerator opening hysteresis is reduced so that the electric travel mode selection tendency that imposes a large load on the electric travel control system is weakened. To change. Thereby, said temperature rise can be suppressed and damage to an electric travel control system can be eliminated.
Alternatively, when the clutch temperature rises due to drive system slip control performed as a driving environment, for example, as a countermeasure against shock at engine start, between the electric travel mode and hybrid travel mode in which engine start (drive system slip control) occurs frequently The hysteresis of the accelerator opening is changed so that the switching at is difficult. As a result, the above-described temperature rise can be suppressed and the problem regarding the early deterioration in the slip control unit of the drive system can be solved.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 shows a power train of a front engine / rear wheel drive hybrid vehicle equipped with a hybrid drive device to which the mode switching control device of the present invention can be applied, where 1 is an engine and 2 is drive wheels (left and right rear wheels). is there.
In the power train of the hybrid vehicle shown in FIG. 1, the automatic transmission 3 is arranged in tandem at the rear of the engine 1 in the longitudinal direction of the vehicle in the same manner as a normal rear wheel drive vehicle, and the engine 1 (crankshaft 1a) is rotated. A motor / generator 5 is provided in combination with the shaft 4 that transmits to the input shaft 3a of the automatic transmission 3.

The motor / generator 5 functions as a motor or a generator (generator), and is disposed between the engine 1 and the automatic transmission 3.
More specifically, a first clutch 6 is inserted between the motor / generator 5 and the engine 1 and, more specifically, between the shaft 4 and the engine crankshaft 1a, and the engine 1 and the motor / generator 5 are disconnected by the first clutch 6. Join as possible.
Here, the first clutch 6 is assumed to be capable of continuously changing the transmission torque capacity. For example, the first clutch 6 is a wet type engine that can change the transmission torque capacity by continuously controlling the clutch hydraulic oil flow rate and the clutch hydraulic pressure with a proportional solenoid. It consists of a plate clutch.

More specifically, a second clutch 7 is inserted between the motor / generator 5 and the automatic transmission 3 and more specifically between the shaft 4 and the transmission input shaft 3a. The second clutch 7 causes the motor / generator 5 and the automatic transmission to be inserted. 3 are separably connected.
Similarly to the first clutch 6, the second clutch 7 can be continuously changed in transmission torque capacity. For example, the proportional torque solenoid can continuously control the clutch hydraulic oil flow rate and clutch hydraulic pressure to change the transmission torque capacity. It consists of possible wet multi-plate clutch.

The automatic transmission 3 determines a transmission system path (shift stage) by selectively engaging and releasing a plurality of friction elements (clutch, brake, etc.) by combining and releasing these friction elements. .
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,
It is used for vehicle travel.
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.

In the power train of FIG. 1 described above, low load /
When the electric travel (EV) mode used at the low vehicle speed is required, the first clutch 6 is released, the second clutch 7 is engaged, and the automatic transmission 3 is set in the power transmission state.

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.
Then, the rotation from the transmission output shaft 3b reaches the rear wheel 2 via the differential gear device 8, and the vehicle can be electrically driven (EV traveling) only by the motor / generator 5.

When a hybrid travel (HEV) mode used during high speed travel or heavy load travel is required, both the first clutch 6 and the second clutch 7 are engaged, and the automatic transmission 3 is brought into a power transmission state. The engine start for switching from the electric travel (EV) mode to the hybrid travel (HEV) mode is performed by connecting the first clutch 6 and increasing the rotation of the engine 1 with the torque of the motor / generator 5.
In the hybrid running (HEV) mode, the output rotation from the engine 1 or 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 The rotation to the input shaft 3a is shifted according to the selected gear position 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 hybrid-driven (HEV-driven) by both the engine 1 and the motor / generator 5.

  In such HEV traveling, when the engine 1 is operated with the optimal fuel efficiency, if the energy becomes surplus, the surplus energy is converted into electric power by operating the motor / generator 5 as a generator by this surplus energy, and this generated power is converted into electric power. By accumulating power to be used for driving the motor of the motor / generator 5, the fuel consumption of the engine 1 can be improved.

  In FIG. 1, a second clutch 7 that releasably couples the motor / generator 5 and the drive wheel 2 is interposed between the motor / generator 5 and the automatic transmission 3. In addition, even when the second clutch 7 is interposed between the automatic transmission 3 and the differential gear device 8 as shown in FIG.

In FIGS. 1 and 2, a dedicated second clutch 7 is added before or after the automatic transmission 3. In addition, as the second clutch 7, as shown in FIG. 3, a friction element for selecting a forward shift stage or a friction element for selecting a reverse shift stage existing in the automatic transmission 3 may be used.
In this case, in addition to the second clutch 7 fulfilling the mode selection function described above, the automatic transmission is put into a power transmission state when engaged to fulfill this function, and a dedicated second clutch is not required and the cost is reduced. The top is very advantageous.

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 FIGS. 1 to 3 are controlled by a system as shown in FIG.
In the following, the power train of the hybrid vehicle uses a friction element for selecting a forward shift stage or a friction element for selecting a reverse shift stage existing in the automatic transmission 3 as the second clutch 7 as shown in FIG. The explanation is expanded for the case of.

  The control system of FIG. 4 includes an integrated controller 20 that integrally controls the operating point of the power train. The operating point of the power train includes the target engine torque tTe, the target motor / generator torque tTm, and the target transmission of the first clutch 6. It is defined by the torque capacity tTc1 and the target transmission torque capacity tTc2 of the second clutch 7.

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 the input rotation sensor 13 for detecting the transmission input rotation speed Ni,
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 state of the engine 1;
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 the transmission oil temperature sensor 17 for detecting the hydraulic oil temperature TEMPat of the automatic transmission 3 representing the temperature of the second clutch 7,
A signal from the electric travel control system cooling water temperature sensor 18 for detecting the coolant temperature TEMPmg of the electric travel control system including the motor / generator 5 and the inverter 10 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 FIGS.

The integrated controller 20 includes the accelerator opening APO, the battery charge state SOC,
In addition, the operation mode (EV mode, HEV mode) that can realize the driving force of the vehicle desired by the driver is selected from the transmission output speed No (vehicle speed VSP), and the target engine torque tTe, target motor / The generator torque tTm, the target first clutch transmission torque capacity tTc1, and the target second clutch transmission torque capacity tTc2 are respectively calculated to perform driving force control.

The target engine torque tTe calculated by the integrated controller 20 is supplied to the engine controller 21, and the target motor / generator torque tTm calculated by the integrated controller 20 is 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 (or the rotational speed Nm) of the motor / generator 5 becomes the target motor / generator torque tTm.
The integrated controller 20 supplies a solenoid current corresponding to the calculated target first clutch transmission torque capacity tTc1 to an engagement control solenoid (not shown) of the first clutch 6, and the transmission torque capacity Tc1 of the first clutch 6 transmits the target. The first clutch 6 is subjected to engagement force control so as to coincide with the torque capacity tTc1.
Further, the integrated controller 20 supplies a solenoid current corresponding to the calculated target second clutch transmission torque capacity tTc2 to an engagement control solenoid (not shown) of the second clutch 7, and the transmission torque capacity Tc2 of the second clutch 7 is the target. The second clutch 7 is individually controlled to be engaged so as to match the second clutch transmission torque capacity tTc2.

Here, the mode switching control (mode selection control) between the EV traveling mode ← → HEV traveling mode according to the present invention, which is executed by the integrated controller 20, will be described with reference to the control program of FIG.
In step S1 of FIG. 5, the vehicle speed VSP, the transmission hydraulic oil temperature TEMPat, and the electric travel control system cooling water temperature TEMPmg are read.
Next, in step S2, a set accelerator opening α for EV → HEV determination is searched based on a set accelerator opening line for EV → HEV switching determination determined in advance as exemplified by a solid line in FIG.

  Here, a setting accelerator opening line for EV → HEV switching determination (EV → HEV determination setting accelerator opening α) illustrated by a solid line in FIG. 6 will be described. This is to determine that switching from EV mode to HEV mode with engine start should be performed when the accelerator opening APO is greater than or equal to this EV → HEV determination accelerator opening α for each vehicle speed VSP. is there. As shown in FIG. 6, the EV → HEV determination setting accelerator opening α is constant regardless of the vehicle speed VSP in a predetermined vehicle speed range. The set accelerator opening α for EV → HEV determination is the upper limit of the accelerator opening APO for EV travel leaving a margin for the motor torque of the motor / generator 5 required for engine startup when switching from EV to HEV mode. Is determined for each vehicle speed VSP, and is obtained in advance through experiments or the like. Therefore, if EV travel is performed with an accelerator opening APO that is larger than the set accelerator opening line for EV → HEV switching determination (EV → HEV determination accelerator opening α), motor / generator 5 consumes a large torque for traveling Thus, the torque required to start the engine 1 cannot be generated when the EV → HEV mode is switched, and as a result, the transition from the EV mode to the HEV mode cannot be performed.

In the next step S3, the normal accelerator HEV → EV determination set accelerator opening β is searched based on the set accelerator opening line for HEV → EV switching determination at room temperature that is set in advance as exemplified by the broken line in FIG. To do.
Here, a set accelerator opening line for determining switching from HEV to EV at normal temperature (set accelerator opening β for HEV to EV determination at normal temperature) will be described. This is because when the accelerator opening APO is less than the HEV → EV judgment set accelerator opening β for each vehicle speed VSP at the temperature (normal temperature) when the warm-up operation is completed, the EV is switched from HEV mode with engine stop. This is for determining that switching to the mode should be performed. HEV → EV judgment set accelerator opening β at room temperature is set on the lower accelerator opening side than the EV → HEV switching judgment set accelerator opening line (EV → HEV judgment setting accelerator opening α) indicated by a solid line .

Accordingly, a set accelerator opening line for determining the changeover of HEV → EV at normal temperature shown by the broken line in FIG. 6 (set accelerator opening β for the HEV → EV determination at normal temperature) and the EV → HEV change determination shown by the solid line in FIG. The accelerator opening hysteresis ΔAPO exists between the set accelerator opening line (EV → HEV determination setting accelerator opening α). The set accelerator opening line for determining the switching between HEV and EV at normal temperature (HEV at normal temperature → setting accelerator opening β for determining EV) shown by a broken line and shown by a broken line in FIG. 6 is a solid line so that the hysteresis ΔAPO increases as the vehicle speed decreases. With respect to the set accelerator opening line for EV → HEV switching determination (EV → HEV determination set accelerator opening α) shown in FIG.
Note that the set accelerator opening β for HEV → EV determination at room temperature illustrated in FIG. 6 is not limited to a constant gradient with respect to a decrease in the vehicle speed, and for example, those that change stepwise are also included in the present invention. included.

In the next step S4, from the vehicle speed VSP and the transmission hydraulic fluid temperature TEMPat (temperature of the second clutch 7), the set accelerator opening line for determining the HEV → EV switching at normal temperature (HEV → EV determining set accelerator at normal temperature) The oil temperature correction coefficient Ktempat (0 <Ktempat ≦ 1) for the opening degree β) is searched. Further, in step S4, a set accelerator opening curve (HEV → EV switching judgment at normal temperature) from the vehicle speed VSP and the electric travel control system cooling water temperature TEMPmg (temperature of the electric travel control system including the motor / generator 5 and the inverter 10) ( Search the water temperature correction coefficient Ktempmg (0 <Ktempmg ≦ 1) for HEV → EV judgment set accelerator opening β at normal temperature. The oil temperature correction coefficient Ktempat (0 <Ktempat ≦ 1) and the water temperature correction coefficient Ktempmg (0 <Ktempmg ≦ 1) are smaller as the corresponding temperature is higher, and are smaller as the vehicle speed is lower.

In the next step S5, by the multiplication of the oil temperature correction coefficient Ktempat and the water temperature correction coefficient Ktempmg, the set accelerator opening line for normal temperature HEV → EV switching determination (normal temperature HEV → EV determination set accelerator opening β) A final temperature correction coefficient Ktemp (= Ktempat × Ktempmg) is obtained.
In the next step S5, the HEV → EV determination set accelerator opening β at normal temperature is multiplied by the above-mentioned final temperature correction coefficient Ktemp to set the HEV → EV determination set accelerator opening γ at high temperature (= β × Ktemp). )

  As described above, the oil temperature correction coefficient Ktempat (0 <Ktempat ≦ 1) and the water temperature correction coefficient Ktempmg (0 <Ktempmg ≦ 1) are smaller as the temperature is higher and the vehicle speed is lower. As a result, the final temperature correction coefficient Ktemp obtained by the multiplication described above is also smaller as the temperature is higher, within the range of (0 <Ktemp ≦ 1). Further, the final temperature correction coefficient Ktemp decreases as the vehicle speed decreases. Therefore, the high temperature HEV → EV determination set accelerator opening γ (= β × Ktemp) obtained by correcting the temperature of the HEV → EV determination set accelerator opening β by this Ktemp is a certain transmission hydraulic fluid. An example of a combination of the temperature TEMPat (temperature of the second clutch 7) and the electric travel control system cooling water temperature TEMPmg (temperature of the electric travel control system including the motor / generator 5 and the inverter 10) is as shown by a one-dot chain line in FIG. It will have characteristics.

That is, the setting accelerator opening line for high temperature HEV → EV switching determination (high temperature HEV → EV determination setting accelerator opening γ), as shown in FIG. The hysteresis ΔAPO between the set accelerator opening line for EV → HEV switching determination (EV → HEV determination set accelerator opening α) is larger than the line (HEV → EV determination set accelerator opening β) Is done. The hysteresis ΔAPO increases as the transmission hydraulic oil temperature TEMPat (temperature of the second clutch 7) and the electric travel control system cooling water temperature TEMPmg (temperature of the electric travel control system including the motor / generator 5 and the inverter 10) increase. It is further increased, and it is increased as the vehicle speed becomes lower.
However, since Ktemp = 1 at normal temperature, the setting accelerator opening line for high temperature HEV → EV switching judgment (high temperature HEV → EV judgment setting accelerator opening γ) is HEV → EV switching at normal temperature. Needless to say, it corresponds to the set accelerator opening line for determination (HEV at normal temperature → set accelerator opening β for EV determination).

  In the next step S7, it is checked whether the current selection mode is the EV mode or the HEV mode. If the EV mode is selected, it is checked in step S8 whether or not the accelerator opening APO is equal to or larger than the EV → HEV determination setting accelerator opening α. Here, if APO ≧ α, switching from the EV mode to the HEV mode is performed in step S9. On the other hand, if APO ≧ α is not satisfied in step S8, the process proceeds to step S10. In step S10, the current EV mode is maintained.

  When it is determined in step S7 that the current selection mode is the HEV mode, the process proceeds to step S11. In step S11, it is checked whether or not the accelerator opening APO is less than the high temperature HEV → EV determination set accelerator opening γ (at normal temperature, it matches the normal temperature HEV → EV determination set accelerator opening β). If APO <γ, the process proceeds to step S12. In step S12, the HEV mode is switched to the EV mode. On the other hand, if APO <γ is not satisfied in step S11, the process proceeds to step S13. In step S13, the current HEV mode is held.

  According to the mode switching control device according to the above-described embodiment, when the EV → HEV mode switching condition of the accelerator opening APO ≧ α is satisfied, the mode switching from the electric travel (EV) mode to the hybrid travel (HEV) mode is performed. Do. Further, when the HEV → EV mode switching condition of the accelerator opening APO <γ is satisfied, the hybrid traveling (HEV) mode is switched to the electric traveling (EV) mode. Here, the hysteresis ΔAPO (= α−γ) of the accelerator opening between the EV → HEV mode switching condition (APO ≧ α) and the HEV → EV mode switching condition (APO <γ) is determined as the vehicle operating state ( Since it is changed as described above according to the vehicle speed VSP and the like and the driving environment (temperatures TEPMat, TEMPmg), the following effects can be obtained.

That is, when the vehicle travels at a relatively low speed in, for example, an urban area and tends to travel while greatly changing the accelerator opening APO, the hysteresis ΔAPO ( = Α−γ) is set large.
As a result, in response to the large change in the accelerator opening, the shift from the electric drive (EV) mode to the hybrid drive (HEV) mode with engine start, or conversely, the engine stop from the hybrid drive (HEV) mode is accompanied. It is possible to prevent frequent transition to the electric travel (EV) mode. As a result, it is possible to avoid problems related to the deterioration of fuel consumption and the deterioration of drivability due to the frequent mode switching.

  For example, if the vehicle is traveling at a relatively high speed on a suburb or highway and tends to travel while slightly changing the accelerator opening APO, the vehicle speed VSP is high, as shown in FIG. The hysteresis ΔAPO (= α−γ) is set small. As a result, mode switching is easily caused by the small change in the accelerator opening. As a result, when the motor / generator torque and the battery storage state SOC (carryable electric power) are those that can be electrically driven, the hybrid vehicle can be surely switched to the electric travel (EV) mode. It is possible to enjoy the fuel efficiency improvement effect that is a characteristic of.

Further, in the present embodiment, the change in the accelerator opening hysteresis ΔAPO is not limited to the vehicle speed condition (vehicle operating state) as described above. In addition, the above hysteresis ΔAPO (= α−γ) can be changed according to the driving environment (temperatures TEPMat, TEMPmg), and the transmission hydraulic oil temperature TEMPat (temperature of the second clutch 7) is higher than that at normal temperature. As a result, the hysteresis ΔAPO (= α−γ) is increased. Further, as the electric travel control system cooling water temperature TEMPmg (temperature of the electric travel control system including the motor / generator 5 and the inverter 10) becomes higher than that at room temperature, the hysteresis ΔAPO (= α−γ) is increased. I did it.
As a result, for example, when the electric travel control system including the motor / generator 5 and the inverter 10 rises in temperature due to a large load, or the slip control of the second clutch 7 in the drive system is performed as a countermeasure against shock at engine start, the clutch When the temperature of 7 rises, the above-mentioned increased hysteresis ΔAPO (= α−γ) weakens the tendency to select the electric travel (EV) mode that imposes a heavy load on the electric travel control system, or starts the engine ( It is possible to make it difficult to switch between the electric travel (EV) mode and the hybrid travel (HEV) mode in which the slip control of the second clutch 7 occurs frequently.
As a result, the above temperature rise can be suppressed, and the problems relating to the damage to the electric travel control system and the early deterioration of the second clutch 7 and its hydraulic fluid can be solved.

  In this embodiment, as shown in FIG. 6, the hysteresis ΔAPO (= α−γ) is illustrated in accordance with the driving state of the vehicle (vehicle speed VSP, etc.) and the driving environment (temperatures TEPMat, TEMPmg) so as to obtain the above-described effects. When changing to EV, the setting accelerator opening line α for EV → HEV switching determination is unchanged, and the intended purpose is achieved by changing the setting accelerator opening lines β, γ for HEV → EV switching determination. . Thereby, the following effects can be obtained.

  In other words, as described above, the EV → HEV switching determination setting accelerator opening line α is an accelerator for EV traveling with a margin for the motor torque of the motor / generator 5 necessary for starting the engine during EV → HEV mode switching. Usually, the upper limit of the opening APO is determined for each vehicle speed VSP. Therefore, if EV driving is performed with an accelerator opening APO larger than the EV → HEV switching determination setting accelerator opening line α, the motor / generator 5 consumes a large torque for driving, and the engine 1 is switched when the EV → HEV mode is switched. The torque required to start the engine cannot be generated, and the EV mode cannot be switched to the HEV mode.

As can be seen from this, when the hysteresis ΔAPO (= α−γ) is increased, the engine start by the motor / generator 5 is made when the set accelerator opening line α for EV → HEV switching determination is changed in the large accelerator opening direction. Cannot be switched from EV mode to HEV mode.
However, as in this embodiment, the hysteresis ΔAPO (= α−γ) is obtained by changing the setting accelerator opening lines β and γ for HEV → EV switching determination instead of the setting accelerator opening line α for EV → HEV switching determination. When changing the above, the above-mentioned adverse effects are not caused.

It is a schematic plan view showing a power train of a hybrid vehicle to which the mode switching control device of the present invention can be applied. It is a schematic plan view which shows the power train of the other hybrid vehicle which can apply the mode switching control apparatus of this invention. It is a schematic plan view which shows the power train of the further another hybrid vehicle which can apply the mode switching control apparatus of this invention. FIG. 4 is a block diagram showing a control system for the power train shown in FIGS. 5 is a flowchart of a mode switching control program executed by an integrated controller in the control system of FIG. FIG. 6 is an EV mode region and HEV mode region diagram used for the mode switching control of FIG.

Explanation of symbols

1 Engine 2 Drive wheel (rear wheel)
3 Automatic transmission 4 Transmission shaft 5 Motor / generator 6 First clutch 7 Second clutch 8 Differential gear unit 9 Battery
10 Inverter
11 Engine rotation sensor
12 Motor / generator rotation sensor
13 Transmission input rotation sensor
14 Transmission output rotation sensor
15 Accelerator position sensor
16 Battery charge sensor
17 Transmission fluid temperature sensor
18 Electric travel control system coolant temperature sensor
20 Integrated controller
21 Engine controller
22 Motor / generator controller

Claims (7)

Provide the engine and motor / generator as the power source, stop the engine, and at least the accelerator opening between the electric travel mode using only the power from the motor / generator and the hybrid travel mode using the power from both the engine and the motor / generator In a hybrid vehicle that selects and switches based on
The accelerator opening hysteresis between the mode switching condition from the electric driving mode to the hybrid driving mode and the switching condition from the hybrid driving mode to the electric driving mode is changed according to the driving state and driving environment of the vehicle. and,
The hybrid vehicle mode switching control device, wherein the vehicle operating state and traveling environment are vehicle speeds, and the hysteresis of the accelerator opening is increased as the vehicle speed decreases . In the mode switching control device according to claim 1 ,
A mode switching control device for a hybrid vehicle, characterized in that the mode switching condition from the electric travel mode to the hybrid travel mode is maintained unchanged regardless of the vehicle speed . In the mode switching control device according to claim 1 ,
The setting accelerator opening for determination that becomes a switching condition from the hybrid travel mode to the electric travel mode is reduced as the vehicle speed is lower,
A hybrid vehicle mode switching control device, characterized in that the setting accelerator opening for determination that serves as a mode switching condition from the electric traveling mode to the hybrid traveling mode is maintained unchanged regardless of the vehicle speed. In the mode switching control device according to any one of claims 1 to 3 ,
The hybrid vehicle mode switching control apparatus, wherein the hysteresis of the accelerator opening is increased as the temperature of the electric travel control system including the motor / generator is higher. A hybrid vehicle is provided with a first clutch capable of continuously changing the transmission torque capacity between the engine and the motor / generator, and a second clutch capable of continuously changing the transmission torque capacity between the motor / generator and the driving wheel. Intervened,
By stopping the engine, releasing the first clutch and engaging the second clutch, it is possible to select the electric travel mode using only the power from the motor / generator, and by engaging both the first and second clutches, the engine The mode switching control device according to any one of claims 1 to 4 , wherein a hybrid travel mode based on power from both the motor and the generator can be selected.
The hybrid vehicle mode switching control device, wherein the hysteresis of the accelerator opening is increased as the temperature of the second clutch is higher. Provide the engine and motor / generator as the power source, stop the engine, and at least the accelerator opening between the electric travel mode using only the power from the motor / generator and the hybrid travel mode using the power from both the engine and the motor / generator In a hybrid vehicle that selects and switches based on
The accelerator opening hysteresis between the mode switching condition from the electric driving mode to the hybrid driving mode and the switching condition from the hybrid driving mode to the electric driving mode is changed according to the driving state and driving environment of the vehicle. And
The hybrid vehicle mode switching control apparatus, wherein the hysteresis of the accelerator opening is increased as the temperature of the electric travel control system including the motor / generator is higher. An engine and a motor / generator are provided as power sources, and a first clutch capable of continuously changing the transmission torque capacity between the engine and the motor / generator is interposed between the motor / generator and the drive wheels. With a second clutch that can be changed,
The engine is stopped, the electric travel mode by only the power from the motor / generator by engaging the second clutch while releasing the first clutch, the engine by engaging both the first clutch and the second clutch and the motor / In a hybrid vehicle that selects and switches between hybrid driving modes based on power from both generators based on at least the accelerator opening ,
The accelerator opening hysteresis between the mode switching condition from the electric driving mode to the hybrid driving mode and the switching condition from the hybrid driving mode to the electric driving mode is changed according to the driving state and driving environment of the vehicle. And
The hybrid vehicle mode switching control device, wherein the hysteresis of the accelerator opening is increased as the temperature of the second clutch is higher.

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