JP2012086738A - Mode switching control device for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To switch a second clutch from a slipped state to an engaged state without causing shock after an engine is started when a mode is switched from an electronic driving mode to a hybrid driving mode.SOLUTION: At t2, an engine is started by receiving an increase of gas pedal opening APO, and, when the number of revolutions of the engine Ne and an engine torque Te increase due to cranking in response to the start of the engine, even if at t5, slip rotation of the second clutch CL2 becomes equal to or lower than slip rotation which allows shift to HEV, and further, at t6, a vehicle speed is equal to or higher than a vehicle speed which allows shift to HEV, the second clutch CL2 is maintained at a slip-engaged state to delay switching to a full-engaged state until the engine torque Te after the start of the engine becomes a stable torque which allows shift to a hybrid driving mode at t7, and switching is carried out at t7 to thereby shift the mode to an HEV mode.

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 mode switching control device for a hybrid vehicle that has taken a shock countermeasure when switching from an EV mode to an HEV mode with engine start.

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 capable of changing the transmission torque capacity is interposed between the electric motor and the driving 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 the mode from the former EV mode to the latter HEV mode.
In switching the mode with such engine start, in order to prevent engine start shock, the engine is cranked by engaging the first clutch while the second clutch is slipped, and the engine is started.

For this reason, after the engine is started at the start of the engine, it is necessary to completely engage the second clutch from the slip state. However, Patent Document 1 discloses the following as an engagement control technique for the second clutch. is suggesting.
That is, when the slip rotation of the second clutch becomes less than the set value, it is determined that the engine has been started, and the second clutch is completely engaged from the slip state.

JP 2010-030486 A

However, the above-described hybrid vehicle mode switching control causes the following problems.
That is, the engine torque of the engine immediately after starting is still unstable, and in the prior art, even when the engine torque is still unstable in this way, the slip rotation of the second clutch has become less than the set value. When it is determined that the engine has been started, the second clutch is completely engaged from the slip state.

  By the way, if the second clutch is completely engaged from the slip state while the engine torque immediately after starting is unstable, the electric motor to be performed before the second clutch is completely engaged due to the unstable engine torque. A torque step occurs between the motor torque during motor speed control and the motor torque during electric motor torque control that should be performed after the second clutch is fully engaged. There was a problem of causing a switching shock.

  The present invention provides a mode switching control device for a hybrid vehicle that solves the above problem by delaying the complete engagement of the second clutch until the engine torque during start-up stabilizes so as not to cause the above problem. The purpose is to propose.

For this purpose, the hybrid vehicle mode switching control apparatus 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 power sources, 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 is interposed between the electric motor and the driving wheel. It has been made.

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 from the electric travel mode to the hybrid travel mode, the engine is started by engaging the first clutch with the second clutch slipped.

The mode switching control device of the present invention is provided with second clutch engagement delay means for such a hybrid vehicle, and by this second clutch engagement delay means,
While the engine is starting, the second clutch is maintained in the slip state until the engine torque reaches the hybrid travel mode transition permission torque, and is characterized in that the complete engagement of the second clutch is delayed.

According to the above-described hybrid vehicle mode switching control device according to the present invention,
In order to delay the complete engagement of the second clutch while keeping the second clutch in the slip state until the engine torque becomes the hybrid travel mode transition permission torque during the engine start at the time of switching from the electric travel mode to the hybrid travel mode,
While the engine torque is still unstable immediately after starting, the second clutch is never completely engaged from the slip state.

  Therefore, according to the mode switching control device of the present invention, the problem caused by completely engaging the second clutch from the slip state while the engine torque immediately after starting is unstable, that is, due to the unstable engine torque. Thus, the torque of the electric motor during the rotational speed control before the second clutch is completely engaged is different from the torque of the electric motor during the torque control after the second clutch is completely engaged. It is possible to avoid the problem that a mode switching shock occurs when the mode is switched to the hybrid travel mode.

1 is a schematic plan view illustrating a power train of a hybrid vehicle to which a mode switching control device of 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. FIG. 3 is a flowchart showing an engagement control program for a second clutch executed by an integrated controller in the control system shown in FIG. 2 at the time of EV → HEV mode switching. FIG. 5 is a functional block diagram showing a calculation procedure of HEV mode transition permission delay timer set time used in the control program in FIG. 5 is an operation time chart related to the engagement control of the second clutch at the time of EV → HEV mode switching 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 mode switching control device 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 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 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 the clutch stroke sensor 17 for detecting the stroke St of the first clutch 6 is input.

  Among the sensors described above, the engine rotation sensor 11, the motor / generator rotation sensor 12, the input rotation sensor 13, the output rotation sensor 14, and the clutch stroke sensor 17 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 of embodiment>
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.

  However, if the second clutch 7 (CL2) is completely engaged from the slip engagement state when the slip rotation of the second clutch 7 (CL2) becomes the HEV transition permission slip rotation, the following problems occur.

As shown in Fig. 6, as a result of starting by depressing the accelerator pedal at the instant t1, the input shaft conversion value (No x gear ratio) and the vehicle speed of the motor torque Tm, motor rotation speed Nm, transmission output rotation speed No are shown When the engine start is started in response to the increase in the accelerator opening APO at the instant t2, and as a result, the engine speed Ne and the engine torque Te increase as shown in the figure,
The above engagement control of the second clutch 7 (CL2) is the slip of the second clutch 7 (CL2), which is the difference between the input shaft converted value (No x gear ratio) of the transmission output speed No and the motor speed Nm. The second clutch 7 (CL2) is unconditionally completely engaged from the slip engagement state at the instant t5 when the rotation becomes the HEV transition permission slip rotation.

  However, immediately after the engine is started at the instant t5, the engine torque Te is unstable as shown by α1 in FIG. 6, and the above-described engagement control of the second clutch 7 (CL2) is still in this way. Even when it is unstable, if the slip rotation of the second clutch 7 (CL2) becomes the HEV transition permission slip rotation (t5), the second clutch 7 (CL2) is unconditionally completely engaged from the slip engagement state. .

By the way, if the second clutch 7 (CL2) is completely engaged from the slip state while the engine torque Te immediately after starting is unstable, the second clutch 7 (CL2) is caused by the unstable engine torque α1. Between the motor torque during the rotation control of the motor / generator 5 to be performed before the complete engagement of the motor and the motor torque during the torque control of the motor / generator 5 to be performed after the second clutch 7 (CL2) is completely engaged A step occurs.
This torque step causes the vehicle acceleration G to be drawn as illustrated by α2 in FIG. 6, and causes a mode switching shock when the EV → HEV mode is switched with the engine starting.

In this embodiment, the above-mentioned problem is solved by delaying the complete engagement of the second clutch 7 (CL2) until the engine torque Te during start-up is stabilized so as not to cause the above-mentioned shock problem. To do.
Therefore, in this embodiment, the integrated controller 20 executes the control program of FIG. 4 when the EV → HEV mode is switched with engine start, and switches the state of the second clutch 7 (CL2) from the slip engagement state to the complete engagement state. Do it like this.

  First, in step S11, it is checked whether or not the vehicle is in the transient mode (WSC) mode between the EV mode and the HEV mode. If it is not the WSC mode, the second clutch 7 (CL2) does not need to be engaged, so the control is continued If it is finished and the WSC mode is selected, control proceeds to step S12 and subsequent steps, and the engagement control of the second clutch 7 (CL2) is performed as follows.

  In step S12, it is checked whether or not the vehicle speed is equal to or higher than the HEV transition permitted vehicle speed illustrated in FIG. Then, the control returns to step S11 to stand by, and if it is equal to or higher than the HEV transition permission vehicle speed, the control proceeds to step S13.

  In step S13, it is checked whether or not the slip rotation | Nm− (No × gear ratio) | of the second clutch 7 (CL2) is equal to or less than the HEV transition permitted slip rotation illustrated in FIG. If the rotation is not less than the rotation, the engagement control of the second clutch 7 (CL2) is not yet required. Therefore, the control returns to step S11 and waits. If the rotation is less than the HEV transition permission slip rotation, the control proceeds to step S14.

In step S14, it is checked whether or not the engine torque Te after starting is stable depending on whether or not the engine torque Te is within the HEV transition permission engine torque range illustrated in FIG.
While it is determined in step S14 that the engine torque Te is not within the HEV transition permitted engine torque range, that is, while it is determined that the engine torque Te is not yet stable immediately after starting, the engagement control of the second clutch 7 (CL2) is performed. If this is done, the above-mentioned shock problem will occur, so control returns to step S11 and waits.
When it is determined in step S14 that the engine torque Te is within the HEV transition permission engine torque range, that is, when it is determined that the engine torque Te has become stable upon completion of starting, the control proceeds to step S15.

Here, the HEV transition permission engine torque range will be described. As shown in FIG. 6, the HEV transition permission engine torque range is set to a predetermined range before and after the target engine torque in the HEV mode according to the vehicle driving state by the driver. It is determined.
In determining whether or not the engine torque Te is within the HEV transition permission engine torque range in step S14, the engine torque Te is estimated, the target engine torque in the HEV mode is obtained from the operating state, and the target engine torque This determination can be made based on whether or not there is an estimated value of the engine torque Te within a predetermined range.

  However, the determination in step S14 is not limited to this. As shown in FIG. 6, the HEV shifts to a predetermined range before and after the target motor torque tTm in the HEV mode according to the vehicle driving state by the driver. The allowable motor torque range is determined, and the deviation between the target motor torque tTm in HEV mode and the actual motor torque Tm is less than the set deviation depending on whether the motor torque Tm is within this HEV transition permitted motor torque range. The determination may be performed depending on whether or not.

  In the determination in step S14, instead of using these torque determinations, as shown in FIG. 6, a HEV mode transition permission delay timer TM that measures the elapsed time from the engine cranking start time t4 is used. Whether or not the engine torque Te has stabilized at the completion of start-up is determined based on whether or not the measurement time (elapsed time from t4 when cranking starts) exceeds the HEV mode transition permission delay timer set time TMs It may be.

By the way, since the set time TMs is for determining whether or not the engine torque Te has stabilized upon completion of the start as apparent from the above, the engine torque from the start of start (cranking start t4) is determined. It is necessary to match with the shortest time until it becomes stable.
However, the minimum time from the start of start (cranking start t4) until engine torque stabilizes is the engine oil temperature Temp (engine temperature), engine torque Te (target engine torque tTe), and engine cranking torque. It varies depending on (first clutch torque capacity tTc1).

Therefore, in the present embodiment, regardless of the engine oil temperature Temp (engine temperature), the target engine torque tTe, and the engine cranking torque (first clutch torque capacity tTc1), the actual start of starting (cranking start) The above set time TMs always matches the shortest time from the time t4) until the engine torque stabilizes.
As shown in FIG. 5, the set time TMs can be changed according to the engine oil temperature Temp (engine temperature), the engine torque Te (target engine torque tTe), and the engine cranking torque (first clutch torque capacity tTc1).

The basic timer set time determination unit 31 in FIG. 5 determines a basic timer set time TMso that serves as a reference for the set time TMs, and inputs this to the multiplier 32.
The basic timer setting time TMso can be determined in any way. For example, when operating in an average environment, the basic timer is the minimum time from the start of start (cranking start t4) until the engine torque stabilizes. The basic timer setting time TMso can be set to a fixed value by setting the setting time TMso.

The timer correction coefficient setting units 33 to 35 set timer correction coefficients (M, A, C) for the basic timer setting time TMso.
The timer correction coefficient setting unit 33 sets a timer correction coefficient M (0 <M ≦ 1) that decreases as the temperature increases according to the engine oil temperature Temp (engine temperature).
The timer correction coefficient setting unit 34 sets a timer correction coefficient A (0 <A ≦ 1) that increases as the engine torque increases according to the target engine torque tTe.
The timer correction coefficient setting unit 35 sets a timer correction coefficient C (0 <C ≦ 1) that decreases as the cranking torque increases according to the engine cranking torque (first clutch torque capacity tTc1).

In the multiplier 32, the HEV mode transition permission delay timer setting time TMs is obtained by sequentially multiplying the basic timer setting time TMso by the timer correction coefficient (M, A, C).
By the way, since the timer correction coefficients (M, A, C) are set as described above, the HEV mode transition permission delay timer setting time TMs becomes shorter as the engine oil temperature Temp (engine temperature) is higher, and the target engine torque tTe The longer it is, the longer it becomes, and the shorter the cranking torque, the shorter.
As a result, regardless of the engine oil temperature Temp (engine temperature), the target engine torque tTe, and the engine cranking torque (first clutch torque capacity tTc1), the engine is actually started from the start (cranking start t4). The HEV mode transition permission delay timer setting time TMs can be matched with the shortest time until the engine torque is stabilized.

In step S12 of FIG. 4, it is determined that the vehicle speed is equal to or higher than the HEV transition permitted vehicle speed (instant t6 in FIG. 6), and in step S13, the slip rotation of the second clutch 7 (CL2) | Nm− (No × gear ratio) | It is determined that the transition permitted slip rotation or less is reached (instant t5 in FIG. 6), and in step S14, the engine torque Te is stably within the HEV transition permitted engine torque range (see FIG. 6) upon completion of engine start. (Instant t7 in FIG. 6) and when all the above three conditions are met (Instant t7 in FIG. 6),
In step S15, the state of the second clutch 7 (CL2) is changed from the slip engagement state to the complete engagement state, and the transition to the HEV mode is permitted.

However, while at least one of the above three conditions in step S12 to step S14 is missing, the control returns to step S11 and waits to change the state of the second clutch 7 (CL2) performed in step S15 (HEV mode). Prohibit and delay.
Therefore, step S14 corresponds to the second clutch engagement delay means in the present invention.

<Effect of Example>
According to the hybrid vehicle mode switching control device according to the embodiment described above,
For example, during the engine start at the time of EV → HEV mode switching as shown in FIG. 6, the slip rotation | Nm− (No × gear ratio) | Even if the vehicle speed exceeds the HEV transition permitted vehicle speed at the instant t6 (step S12) and the engine torque Te becomes the hybrid travel mode transition permitted torque until the instant t7 (step S14), the second clutch 7 (CL2) is kept in the slip engagement state to delay the state switching to the complete engagement state (to delay the transition to the HEV mode by continuing the WSC mode)
The second clutch 7 (CL2) is not completely engaged from the slip engagement state before the instant t7 when the engine torque Te is still unstable immediately after the start.

  Therefore, according to the mode switching control device of the present embodiment, the above-described problem that occurs when the second clutch 7 (CL2) is completely engaged from the slip engagement state while the engine torque Te immediately after starting is unstable, that is, Due to the unstable engine torque, the motor torque of the motor / generator 5 during the rotational speed control before the second clutch 7 (CL2) is completely engaged and the torque after the second clutch 7 (CL2) is completely engaged It is possible to avoid the problem that a torque step occurs between the motor torque of the motor / generator 5 being controlled and a mode switching shock occurs at the time of EV → HEV mode switching accompanying engine start.

Further, as in the mode switching control device of this embodiment, when determining whether or not the engine torque Te is before the instant t7 when the hybrid travel mode transition permission torque is reached, the HEV mode from the cranking start time t4 for starting the engine is determined. When the judgment is made based on whether or not the transition permission delay timer set time TMs has elapsed,
The above determination can be made only by measuring the time from the cranking start time t4 without providing a sensor for detecting torque, which is advantageous in terms of cost.

As in the mode switching control device of the present embodiment, the HEV mode transition permission delay timer set time TMs is set to the engine oil temperature Temp (engine temperature), the target engine torque tTe, and the engine cranking torque (first clutch torque capacity tTc1). Can be changed according to
The higher the engine oil temperature Temp (engine temperature), the shorter the set time TMs, the longer the target engine torque tTe, the longer the set time TMs, and the higher the cranking torque, the shorter the set time TMs. if you did this,
Regardless of the engine oil temperature Temp (engine temperature), target engine torque tTe, and engine cranking torque (first clutch torque capacity tTc1), the engine torque is always from the start of actual start (cranking start t4). The set time TMs can be matched with the shortest time until stabilization, and the period when the engine torque Te is unstable immediately after starting can be determined more accurately, and the HEV mode transition permission delay time can be minimized. The above effects can be achieved.

Further, as in the mode switching control device of this embodiment, when determining the period when the engine torque Te immediately after starting is unstable, as shown in FIG. 6, the target motor in the HEV mode according to the vehicle driving state by the driver A predetermined range before and after the torque tTm is defined as the HEV transition permission motor torque range, and depending on whether or not the motor torque Tm is within this HEV transition permission motor torque range, that is, the target motor torque tTm in the HEV mode, When performing the determination based on whether the deviation from the actual motor torque Tm is less than the set deviation,
Since the engine torque Te immediately after startup is determined based on the motor torque Tm, which has less fluctuation than the engine torque Te, the accuracy of the determination can be improved and the HEV mode transition permission delay time is required The aforementioned effects can be achieved while minimizing.

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
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 Clutch stroke sensor
20 Integrated controller
21 Engine controller
22 Motor / generator controller
31 Basic timer setting time determination section
32 multiplier
33 to 35 Timer correction coefficient setting section

Claims (7)

An engine and an electric motor are provided as power sources, 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 is interposed between the electric motor and the driving wheel. Let
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 In a hybrid vehicle that can select a hybrid driving mode by power from an electric motor and starts the engine by engaging the first clutch while the second clutch is slipped when switching from the electric driving mode to the hybrid driving mode. ,
A second clutch engagement delay means is provided for delaying complete engagement of the second clutch while keeping the second clutch in the slip state until the engine torque reaches the hybrid travel mode transition permission torque during the engine start. A mode switching control device for a hybrid vehicle. In the hybrid vehicle mode switching control device according to claim 1,
The hybrid vehicle mode switching permission torque is a torque value within a predetermined range across a target engine torque in a hybrid travel mode according to a vehicle driving state by a driver. In the hybrid vehicle mode switching control device according to claim 1 or 2,
The second clutch engagement delay means determines whether or not the engine torque is before the hybrid travel mode transition permission torque based on whether or not a set time has elapsed from the start of cranking for engine start. A hybrid vehicle mode switching control device. In the hybrid vehicle mode switching control device according to claim 3,
The mode switching control device for a hybrid vehicle, wherein the set time is set to be shorter as the temperature is higher according to the engine temperature. In the hybrid vehicle mode switching control device according to claim 3 or 4,
The mode switching control device for a hybrid vehicle, characterized in that the set time is set longer as the engine torque increases in accordance with the target engine torque. In the mode switching control device of the hybrid vehicle according to any one of claims 3 to 5,
The mode switching control device for a hybrid vehicle, wherein the set time is set shorter as the cranking torque is larger in accordance with the cranking torque for starting the engine. In the hybrid vehicle mode switching control device according to claim 1 or 2,
The second clutch engagement delay means determines whether or not the engine torque has reached the hybrid travel mode transition permission torque between the target motor torque in the hybrid travel mode according to the vehicle driving state by the driver and the actual motor torque. A mode switching control device for a hybrid vehicle, characterized by determining whether or not the deviation is less than a set deviation.

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