JP5824816B2 - Engine stop control device for hybrid vehicle - Google Patents

Description

The present invention relates to a hybrid vehicle comprising an engine and an electric motor as a power source, the engine and the electric motor being connectable by a first clutch, and the electric motor and a drive wheel being connectable by a second clutch.
In particular, the present invention relates to an engine stop control device that takes measures against sound vibration when the engine is stopped with the first clutch engaged while the non-travel range is selected with the second clutch released.

The hybrid vehicle as described above is already known as described in Patent Document 1, for example.
In this hybrid vehicle, the engine can be stopped, the first clutch can be released, and the second clutch can be engaged to select the electric travel (EV) mode using only the power from the electric motor.
By engaging both the first clutch and the second clutch, a hybrid travel (HEV) mode using power from both the engine and the electric motor can be selected.

On the other hand, in such a hybrid vehicle, when the driver has selected a non-traveling range such as a parking (P) range or neutral (N), power transmission to the driving wheel is unnecessary, so the second clutch is It is released.
While the non-traveling range is selected with the second clutch released in this way, the driver issues an engine stop command by switching the ignition switch from ON to OFF while operating the engine with the first clutch engaged. A situation is assumed.

For example, while the vehicle is stopped in the P range, when the driver knows that the battery charge state (power that can be taken out) has declined and depresses the accelerator pedal to charge the battery, the electric motor is operated by operating the engine and engaging the first clutch. The engine is driven, and the battery is charged by power generation by the motor.
When the battery storage state (carryable power) is restored by such charging, the driver releases the accelerator pedal and issues an engine stop command by switching the ignition switch from ON to OFF.
In response to this, the hybrid vehicle stops the engine while the first clutch is engaged, in order to stop both the engine and the electric motor, together with the P range being selected.

JP 2009-208700 A

However, as described above, when the engine is stopped while the first clutch is engaged during selection of the non-traveling range in which the second clutch is released, the electric motor temporarily takes a large negative value to reduce the engine speed. Since the torque is generated , the absolute value of the large negative torque exceeds the sound vibration allowable torque of the vehicle.

  For this reason, when the large negative torque is suddenly input to the first clutch, a problem in sound vibration is caused, and a problem that a good sound vibration characteristic lowers the commercial value of a hybrid vehicle that is sold.

This problem becomes particularly prominent when the engine is not yet warmed up and the engine is operated at a speed higher than the idling speed when the accelerator pedal is released, for the following reason.
In other words, if the warm-up operation is not finished yet, when the engine is stopped, the engine speed is temporarily reduced from the high speed to the idle speed and then the engine is stopped. This is because the negative torque of the electric motor when the rotation speed is decreased from the high rotation speed to the idle rotation speed increases due to the high rotation speed.

According to the present invention, the magnitude of the negative torque temporarily generated by the electric motor to reduce the engine speed during engine stop control, that is, the torque change amount of the electric motor during engine stop control causes the above-described sound vibration problem. Based on the fact that it is
When the engine stop control is performed without stopping the electric motor, and the engine speed is controlled by the rotation speed control of the electric motor via the first clutch in the engaged state, the engine negative magnitude of the motor torque, that is a negative torque change amount of the electric motor during the engine stop control, settable engine speed reduction control mode to the arbitrary electric motor during stop control of the engine rotational speed reduction control for generating Ri determined by the (electric rotating speed control mode of the motor), in view of allowing suppressed to a small value within the allowable torque range vibration sound of the vehicle,
It is an object of the present invention to provide an engine stop control device for a hybrid vehicle that embodies this idea and solves the above-described problem.

For this purpose, the engine stop control device for a hybrid vehicle according to the present invention is configured as follows.
First, to explain the premise hybrid vehicle,
An engine and an electric motor are provided as power sources, the engine and the electric motor can be connected by a first clutch, and the electric motor and a drive wheel can be connected by a second clutch.

  The engine stop control device of the present invention is characterized in that the hybrid vehicle is provided with the following non-traveling range detection means, first clutch engagement detection means, engine stop command detection means, and electric motor control means.

The non-traveling range detection means detects that the non-traveling range is selected with the second clutch released,
The first clutch engagement detection means detects that the first clutch is engaged,
The engine stop command detection means detects that the engine stop command has been issued.
The electric motor control means operates the electric motor for a predetermined time from the time when it is determined by the above three means that the engine stop command is issued while the first clutch is engaged while the non-traveling range is selected. The torque change amount of the electric motor is kept below a predetermined level for maintaining the negative torque of the electric motor used for the engine speed reduction control accompanying the engine stop command within a sound vibration allowable torque range. The electric motor is controlled.

According to the engine stop control device for a hybrid vehicle according to the present invention described above,
When the engine stop command is issued in the first clutch engaged state while the non-travel range is selected, the electric motor continues to operate for a predetermined time from the time of the engine stop command, and the torque change amount is In order to control the electric motor so that the negative torque of the electric motor used for the engine rotation speed reduction control accompanying the engine stop command is not more than a predetermined level for maintaining the value within the sound vibration allowable torque range,
And continue to operate without stopping the electric motor when the engine is stopped, this by the electric motor becomes possible to control the reduction of the engine rotational speed, thereby the electric motor, temporary described above during lowering of engine rotation speed In addition to not generating a large negative torque, it is possible to suppress the torque change amount of the electric motor that generates the negative torque for the engine speed reduction control to a predetermined level or less.

Therefore, even when the engine that is rotating at a high speed is stopped in the warm-up operation , the negative torque of the electric motor during the engine stop control (engine speed reduction control) does not exceed the sound vibration allowable torque. It can solve the problems related to vibration.

1 is a schematic plan view illustrating a power train of a hybrid vehicle to which an engine stop 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. 3 is a flow chart of an engine stop control program for an engine stop control device according to a first embodiment of the present invention, which is executed by an integrated controller in the control system shown in FIG. 2 when an ignition switch is OFF. 3 is a flow chart of an engine stop control program for an engine stop control device according to a second embodiment of the present invention, which is executed by an integrated controller in the control system shown in FIG. 2 when an ignition switch is OFF. FIG. 5 is an operation time chart of engine stop control when the ignition switch is OFF according to the control program shown in FIGS.

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 engine stop control device of the present invention can be applied.
This hybrid vehicle is based on a front engine / rear wheel drive vehicle (rear wheel drive vehicle) and is a hybrid of this.
In FIG. 1, 1 indicates an engine as a first power source, and 2 indicates driving wheels (rear wheels).

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;
ON / OFF signals from the ignition switch 17 that the driver operates to issue a vehicle driving preparation command and a driving stop command (including an engine stop command);
The selection range signal from the shifter 18 that the driver operates to command the vehicle travel mode, i.e., the parking (P) range signal, the reverse travel (R) range signal, the neutral (N) range signal, and the forward travel (D ) Input the range signal.

  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 required driving force of the vehicle that the driver wants,
Target engine torque tTe, target motor / generator torque tTm, target motor / generator rotation speed tNm, target first clutch transmission torque capacity tTc1 necessary to realize the above required driving force under the selected operation mode, and The target second clutch transmission torque capacity tTc2 is 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 calculates the target drive torque obtained from the transmission output rotational speed No (vehicle speed VSP) and the accelerator opening APO (braking operation force during braking) using the planned target drive force map, the battery storage rate SOC, Based on the planned target operation mode area map based on the vehicle operation status such as accelerator opening APO and transmission output speed No (vehicle speed VSP), the electric travel (EV) mode and hybrid travel (HEV) mode described above To select the target travel mode.

  In the electric drive (EV) mode, as described above, the engine 1 is kept stopped, the first clutch 6 is released, the second clutch 7 is engaged, or the automatic transmission 3 is selected by engaging the slip. In the state (power transmission state), 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 described above, the first clutch 6 is also engaged with the second clutch 7 engaged, and the first clutch 6 is also engaged with the automatic transmission 3 being in the corresponding gear selection state (power transmission state). Both the output rotation from the engine 1 and the output rotation from the motor / generator 5 under torque control are transmitted to the rear wheel 2 under a shift by the automatic transmission 3.

When switching the mode from the hybrid running (HEV) mode to the electric running (EV) mode, the second clutch 7 is changed from the fully engaged state to the slip engaged state, and the motor / generator 5 is controlled in rotation speed while the first clutch The switch to the electric travel (EV) mode is completed by releasing 6 and stopping the activated engine 1.
At this time, since the second clutch 7 is in the slip engagement state, it is possible to absorb the mode switching shock and take a shock countermeasure.

When switching the mode from the electric drive (EV) mode to the hybrid drive (HEV) mode, the first clutch is maintained with the automatic transmission 3 in the corresponding gear selection state (power transmission state) by the slip engagement of the second clutch 7. By the fastening progress control 6 and the rotational speed control of the motor / generator 5, the stopped engine 1 is cranked and started, the engine 1 is brought into the starting state, and the switching to the hybrid running (HEV) mode is completed.
At this time, since the second clutch 7 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 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, it is necessary to completely engage the second clutch 7 from the slip engagement state.

<Engine stop control of the first embodiment>
Unlike the engine stop at the time of mode switching described above, the integrated controller 20 executes the control program shown in FIG. 3 in the engine stop control when the driver issues an engine stop command by switching the ignition switch 17 from ON to OFF. The engine stop control is executed when the ignition switch is OFF as follows.

In step S11, it is checked whether or not the ignition switch 17 is OFF. If the ignition switch 17 is not OFF (if it is ON), in response to the ON of the ignition switch 17 in step S12, the vehicle is ready to travel. Continue.
When it is determined in step S11 that the ignition switch 17 is OFF, that is, when it is determined that an engine stop command has been issued, in step S13, the first clutch 6 is based on the target transmission torque capacity tTc1 of the first clutch 6. Check whether or not is in the fastened state.
Accordingly, step S11 corresponds to the engine stop command detection means in the present invention, and step S13 corresponds to the first clutch engagement detection means in the present invention.

If it is determined in step S13 that the first clutch 6 is not engaged, the present invention does not cause a problem to be solved. Therefore, in response to the ignition switch OFF determination in step S11, the engine 1 is immediately stopped in step S14. Let
If it is determined in step S13 that the first clutch 6 is in the engaged state, it is checked in step S15 whether a non-traveling range of the P range or the N range is selected.
Therefore, step S15 corresponds to the non-traveling range detecting means in the present invention.

  If it is determined in step S15 that the travel range is selected instead of the non-travel range, the engine stop control in the travel range is performed as usual in step S16 in response to the ignition switch OFF determination in step S11.

  If it is determined in step S11 that the ignition switch 17 is OFF, it is determined in step S13 that the first clutch 6 is engaged, and it is determined in step S15 that the non-traveling range is being selected. If an engine stop command is issued by turning OFF the ignition switch 17 while the first clutch 6 is engaged while the range is selected, the control proceeds to step S17 and subsequent steps, and the engine stop control targeted by the present invention is performed. To do.

Before the engine stop control targeted by the present invention after step S17 is described, the necessity thereof will be described below.
As described above, the case where the engine stop command is issued by turning off the ignition switch 17 while the first clutch 6 is engaged while the non-running range is selected includes, for example, the following cases.

For example, while the vehicle is stopped in the P range, if the driver knows that the battery 9 is not fully charged (the power that can be taken out) and depresses the accelerator pedal to charge the battery 9, the engine 1 and the first clutch 6 The motor / generator 5 is driven by the engine by the fastening, and the battery 9 is charged by the power generation by the motor / generator 5.
When the storage state (power that can be taken out) of the battery 9 is restored by such charging, the driver releases the accelerator pedal and issues an engine stop command by switching the ignition switch 17 from ON to OFF.
In response to this, the hybrid vehicle also stops the engine 1 with the first clutch 6 engaged to stop both the engine 1 and the motor / generator 5 in combination with the P range being selected. Will be allowed to.

However, when the engine 1 is stopped in response to the ignition switch 17 being OFF (engine stop command is generated) with the first clutch 6 engaged while the non-traveling range is selected as described above, the motor / generator 5 is Since a large negative torque is temporarily generated in order to reduce the rotational speed Ne, the absolute value of the large negative torque exceeds the sound vibration allowable torque of the vehicle.
In particular, if the warm-up operation of the engine 1 is not yet finished and the engine 1 is operated at a higher speed (Ne> Neid) than the idle speed Neid after the warm-up operation, the engine 1 When stopping, the engine speed Ne is temporarily reduced from the high speed (Ne> Neid) to the idle speed Neid, and then the engine 1 is stopped. However, the engine speed Ne is set to the high speed described above. The negative torque of the motor / generator 5 when reducing from (Ne> Neid) to the idle speed Neid significantly exceeds the allowable vibration vibration of the vehicle due to the high speed (Ne> Neid). .

  For this reason, when the large negative torque of the motor / generator 5 is suddenly input to the first clutch 6, it causes bad effects on sound vibration, and good sound vibration characteristics reduce the commercial value of hybrid vehicles that are sold. This causes the problem.

The present invention intends to solve this problem. Therefore, in this embodiment, first, in step S17, it is determined whether or not the engine 1 is in the above-described high rotation state (Ne> Neid), that is, the negative torque of the motor / generator 5 is determined. It is checked whether or not the noise significantly exceeds the allowable sound vibration torque of the vehicle.
If the engine 1 is not in a high rotation state (Ne> Neid), the above problem does not become significant. Therefore, in step S18, the engine 1 is immediately stopped from the idle rotation speed Neid.

However, when the engine 1 is determined to be in the high rotation state (Ne> Neid) in step S17, the above problem becomes significant. Therefore, in order to solve this problem, in step S19, the engine rotation speed Ne is set to the high rotation speed (Ne). > Neid) once to the idling engine speed Neid and then stopping the engine 1, in step S21, the target engine speed tNm of the motor / generator 5 is decreased by a predetermined change rate ΔNm, and the motor / generator engine speed is reduced. A target motor / generator torque tTm (the amount of change ΔTm) is determined so that Nm follows the target motor rotation speed tNm, which contributes to the control of the motor / generator 5.
Accordingly, step S21 corresponds to the electric motor control means in the present invention.

In the next step S22, it is checked whether or not the communication between the controllers 20 to 22 has been completed (engine stop control end)
Control is returned to step S19 until it is determined that the engine stop control is ended, and the control in steps S19 and S21 is continued. When it is determined that the engine stop control is ended, the control program of FIG. And the control in step S21 is finished, and the stop of the engine 1 is completed.

<Effect of the first embodiment>
The effect of the engine stop control when the ignition switch is OFF in the first embodiment described above with reference to FIG. 3 will be described below with reference to FIG.
FIG. 5 shows that the first pedal is selected during the non-traveling range selection in which the accelerator pedal is released (accelerator opening APO = 0) and the second clutch 7 is released with the target second clutch transmission torque capacity tTc2≈0. The engine stop control is shown when an engine stop command is generated by turning off the ignition switch 17 at an instant t1 in a state where the clutch 6 is engaged with the target first clutch transmission torque capacity tTc1> 0.

  Thus, when the non-travel range is selected and the first clutch 6 is engaged and the engine stop is commanded by turning OFF the ignition switch 17 (momentary t1 in FIG. 5), and the target motor / generator is shown in FIG. If the engine speed Ne is in a high state before the completion of warm-up as shown as the engine speed (tNm = Ne> Neid), step S11, step S13, step S17 and step S19 in FIG. Proceed to step S21.

In step S19, the engine speed Ne is once reduced from a high engine speed (Ne> Neid) to the idle engine speed Neid, and then the engine 1 is instructed to stop. At this time, the engine speed is not considered without any consideration. When the reduction is executed, when the engine speed Ne is reduced from the high engine speed (Ne> Neid) to the idle engine speed Neid, the motor / generator 5 is temporarily set to a large negative value so as to achieve the engine speed reduction with a large step. Because the torque is generated , the absolute value of the large negative torque exceeds the allowable vibration range of the vehicle, and the sound vibration performance deteriorates despite the fact that the vibration performance is a hybrid vehicle sold. This causes the problem of damage.

  However, in this embodiment, when the engine speed Ne is decreased from the high engine speed (Ne> Neid) to the idle engine speed Neid, the target engine speed tNm of the motor / generator 5 is set to one point in FIG. As shown by the chain line, the target motor / generator torque tTm (the amount of change ΔTm) is shown by a one-dot chain line in FIG. 5 so that the motor / generator rotation speed Nm follows this target motor rotation speed tNm. It is determined as shown and contributes to the control of the motor / generator 5.

That is, the motor / generator 5 continues to operate without being stopped even when the engine rotational speed Ne is decreased due to the engine stop, and the motor / generator 5 keeps the decrease in the engine rotational speed Ne during the engine stop control as described above. When the motor speed is controlled, the amount of change ΔTm of the target motor / generator torque tTm during the reduction control of the engine speed Ne is set to the target motor / generator torque tTm within the allowable vibration range of the vehicle. since configured to be suppressed to a degree not to be larger than, goals motor / generator torque tTm to compensate for less than or equal to the value of the sound vibration allowable torque range, a large negative torque of the motor / generator 5 as described above (Vehicle sound vibration) can be solved, and the vibration performance of hybrid vehicles selling sound vibration performance It is possible to avoid the above-described problem that the product value deteriorates due to deterioration.
Needless to say, the predetermined change rate ΔNm of the target motor / generator rotation speed tNm should be as large as possible within a range where this problem can be solved.

The engine stop control in step S19 and step S21 is continued until the instant t2 in FIG. 5 in which it is determined in step S22 that the engine stop control is ended by the end of communication between the controllers 20 to 22,
At the instant t2, the communication Te between the controllers 20 to 22 is terminated, so that the torque Te of the engine 1, the target rotational speed tNm of the motor / generator 5 and the target torque tTm are set to 0, and the engine 1 can be stopped.

In this embodiment, the engine stop motor / generator rotational speed control in step S21 is performed when the engine rotational speed Ne is decreased from the high rotational speed (Ne> Neid) to the idle rotational speed Neid in step S19. Only, that is, only when the sound vibration performance deteriorates significantly,
It is possible to avoid the adverse effect that the engine stop motor / generator rotation speed control in step S21 is performed wastefully.

<Engine stop control of the second embodiment>
In the engine stop control when the driver issues an engine stop command by turning off the ignition switch 17, the integrated controller 20 in FIG. 2 executes the control program in FIG. 4 and stops the engine when the ignition switch is turned off as follows. The same effect can be achieved by performing the control.

Also in this embodiment, the power train of the hybrid vehicle is the same as that shown in FIG. 1, and the control system is the same as that shown in FIG.
The control program in FIG. 4 is obtained by replacing step S21 in the control program in FIG. 3 with step S31, and the same steps as in FIG.

In step S11 of FIG. 4, it is determined that the ignition switch 17 is OFF, in step S13 it is determined that the first clutch 6 is engaged, and in step S15 it is determined that the non-traveling range is being selected, and When it is determined in step S17 that the engine 1 is in a higher rotation state than the idling engine speed Neid after warm-up,
In other words, when a command to stop the engine 1 in the high rotation state is issued by turning off the ignition switch 17 with the first clutch 6 engaged while the non-traveling range is selected,
As in the first embodiment, the engine 1 is stopped after the engine speed Ne is once decreased from the high speed (Ne> Neid) to the idle speed Neid in step S19.

By the way, in this case in the second embodiment (after the instant t1 in FIG. 5), in step S31, the target rotational speed tNm of the motor / generator 5 is set to a predetermined rotational speed as shown by the solid line in FIG. The target engine speed tNm immediately before the engine stop speed control start instant t1 is maintained, and the motor / generator speed Nm matches the target motor speed tNm maintained at the predetermined speed. A motor / generator torque tTm (in FIG. 5, its change amount ΔTm is 0) is determined to contribute to the control of the motor / generator 5.
Therefore, step S31 corresponds to the electric motor control means in the present invention.

  The engine speed reduction control at step S19 and step S31 continues until the instant t2 in FIG. 5 where step S22 determines the end of communication between the controllers 20 to 22 (end of engine stop control), and step S22 ends the engine stop control. Is determined (at instant t2 in FIG. 5), the control program in FIG. 4 is exited to complete the control in step S19 and step S31, and the stop of the engine 1 is completed.

<Effect of the second embodiment>
The effect of the engine stop control when the ignition switch is OFF in the second embodiment described above with reference to FIG. 4 will be described below with reference to FIG.
In this embodiment, when the engine speed Ne is reduced from the high engine speed Ne (Ne> Neid) to the idle engine speed Neid after the instant t1 in FIG. 5, the target speed of the motor / generator 5 is reduced in step S31 in FIG. The number tNm is maintained at a predetermined number of revolutions as shown by the solid line in FIG. 5 (in FIG. 5, the target number of revolutions tNm immediately before the engine / rotation speed control start instant t1 of the motor / generator 5). A target motor / generator torque tTm (the amount of change ΔTm is 0 in FIG. 5) is determined to contribute to the control of the motor / generator 5 so that Nm matches the target motor speed tNm maintained at the predetermined speed. .

For this reason, the motor / generator 5 continues to operate without being stopped even when the engine rotational speed Ne is reduced due to the engine stop control, and the motor / generator 5 keeps the decrease in the engine rotational speed Ne during the engine stop control described above. In this control, the amount of change ΔTm of the target motor / generator torque tTm during the decrease control of the engine speed Ne is less than the allowable vibration range of the vehicle. will be suppressed to such an extent not to largely compensates for the target motor / generator torque tTm for engine rotational speed decrease control is equal to or less than the value of the sound vibration allowable torque range, vibration sound of the the vehicle If the sound vibration performance of a hybrid vehicle sold for sale deteriorates and its commercial value is impaired It is possible to avoid the cormorant said of the problem.
Note that the predetermined rotational speed of the target motor / generator rotational speed tNm to be maintained after the instant t1 in FIG. 5 should be as small as possible within the range where this problem can be solved, and is not necessarily as shown in FIG. The target rotational speed tNm just before the instant t1 is not necessary.

The engine stop control in step S19 and step S31 is continued until the instant t2 in FIG. 5 in which it is determined in step S22 that the engine stop control is ended due to the end of communication between the controllers 20-22.
At the instant t2, the communication Te between the controllers 20 to 22 is terminated, so that the torque Te of the engine 1, the target rotational speed tNm of the motor / generator 5 and the target torque tTm are set to 0, and the engine 1 can be stopped.
However, the end timing of the engine stop control in step S19 and step S31 is not necessarily the end t2 of the engine stop control, and may be before the instant t2 as long as the above-described effect is obtained. When a predetermined time has elapsed from the instant t1, the engine stop control in steps S19 and S31 can be terminated.

In this embodiment, the engine stop motor / generator rotation speed control in step S31 is performed when the engine rotation speed Ne is decreased from the high rotation speed (Ne> Neid) to the idle rotation speed Neid in step S19. Only, that is, only when the sound vibration performance deteriorates significantly,
It is possible to avoid the disadvantage that the engine stop motor / generator rotation speed control in step S31 is performed wastefully.

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 Ignition switch
18 Shifter
20 Integrated controller
21 Engine controller
22 Motor / generator controller

Claims (5)

In a hybrid vehicle that includes an engine and an electric motor as a power source, the engine and the electric motor can be coupled by a first clutch, and the electric motor and a drive wheel can be coupled by a second clutch.
Non-running range detection means for detecting that the second clutch is being released and the non-running range is being selected;
First clutch engagement detection means for detecting that the first clutch is engaged; and
Engine stop command detection means for detecting that the engine stop is commanded;
By these means, the electric motor continues to operate for a predetermined time from the time when it is determined that the engine stop command is issued while the first clutch is engaged during the non-traveling range selection, and the torque of the electric motor Electric motor control for controlling the electric motor so that the amount of change is not more than a predetermined level for maintaining the negative torque of the electric motor used for engine rotation speed reduction control accompanying the engine stop command within a value within the allowable range of sound vibration tolerance And an engine stop control device for a hybrid vehicle. In the hybrid vehicle engine stop control device according to claim 1,
The engine stop control of a hybrid vehicle, wherein the electric motor control means determines the motor torque change amount so that the rotation speed of the electric motor decreases at a predetermined change rate, and is used for controlling the electric motor. apparatus. In the hybrid vehicle engine stop control device according to claim 1,
The electric motor control means determines the amount of change in the motor torque so that the rotation speed of the electric motor is maintained at a predetermined motor rotation speed for the predetermined time, and is used for controlling the electric motor. An engine stop control device for a hybrid vehicle. The engine stop control device for a hybrid vehicle according to any one of claims 1 to 3 ,
The engine stop control device for a hybrid vehicle, wherein the predetermined time is a time from when the engine stop command is detected by the engine stop command detection means to when the engine stop control ends. In the engine stop control device for a hybrid vehicle according to any one of claims 1 to 4 ,
The electric motor control means controls the electric motor when the rotational speed of the engine is once lowered from a high rotational state higher than the idle rotational speed to the idle rotational speed and the engine is stopped after the rotational speed is lowered. An engine stop control device for a hybrid vehicle, characterized in that:

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