JP2006306207A - Engine start method for hybrid drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate overrotation of a motor/generator to prevent an occupant from feeling a sense of incongruity, when slip-engaging a transmission side clutch under a travel in an electric vehicle travelling (EV travel) mode to start an engine, in a one-motor and two-clutch type of hybrid drive unit drive-connected in series with the engine of an internal combustion engine, an engine side clutch, the motor/generator, the transmission side clutch and a transmission. <P>SOLUTION: When starting the engine 3, a tightening capacity of the engine side clutch 8 is increased to transmit a torque necessary for the start of the engine from the motor/generator 7 to the engine 3 (step S7), and the motor/generator 7 compensates the torque necessary for the start of the engine (step S9), when detecting lead-in of a rotation speed in the motor/generator 7 (Yes in step S8). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for starting an engine using the motor in a hybrid vehicle including a motor / generator that is an electric motor and an engine that is an internal combustion engine as a driving power source.

As an invention of a method for starting an engine using the output of a motor / generator during traveling in a serial hybrid vehicle in which an engine and a transmission are drive-coupled and a motor / generator is provided between the engine and the transmission. Conventionally, for example, the one described in Patent Document 1 is known.
The hybrid vehicle described in Patent Document 1 includes a drive system in which an engine is connected to a motor via an engine clutch, and the motor is connected to drive wheels via a starting clutch. When starting the engine while the motor alone is running, the motor rotation speed is increased while the starting clutch is slip-controlled, and when the motor rotation speed reaches a predetermined value, the engine clutch is engaged. Cranking is performed.
JP 2000-255285 A

  However, the conventional one-motor two-clutch hybrid vehicle has the following problems. In other words, after increasing the number of rotations of the motor (also referred to as the rotation speed), the engine clutch is completely engaged and the crankshaft of the engine is rotated. It is necessary to increase the amount of increase. For this reason, there has been a problem that the motor over-rotation (swelling in the engine) unintended by the driver occurs, and this over-rotation sound gives the passenger a sense of incongruity.

  The present invention proposes a method of starting an engine that does not cause over-rotation of the motor.

For this purpose, the engine start method according to the invention is as claimed in claim 1,
The engine output shaft is drive-coupled to the transmission input shaft, and a motor / generator is provided between the engine and the transmission,
In a vehicle hybrid drive device having an engine-side friction element that releasably couples an engine and a motor / generator, and a transmission-side friction element that releasably couples a motor / generator and a transmission,
In starting the engine while the vehicle is running with the engine side friction element released and the transmission side friction element fastened,
Increasing the fastening capacity of the engine side friction element and rotating the engine,
It is provided with a pull-in detection means for detecting pull-in of the rotation speed of the motor / generator due to the rotation, and at the time of the detection, the motor / generator is compensated for a torque equivalent to the fastening capacity of the engine-side friction element. It is.

  According to the engine starting method of the present invention, when the cranking of the engine is started, the retraction of the motor speed is detected, and simultaneously with the detection, the cranking torque is compensated by the motor. Therefore, it is not necessary to increase the rotational speed of the motor in advance, and it is possible to solve the problem that the over-rotation sound of the motor makes the passenger feel uncomfortable.

  In addition, since the output of the motor / generator is controlled to increase to compensate for the torque equivalent to the engagement capacity of the engine-side friction element, that is, the cranking torque, the hybrid vehicle is driven while the motor / generator is running. Even when the engine starting method of the invention is used, stable driving can be realized without any problem in driving driving.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 is a system diagram showing the overall configuration of a drive system for a power train of a vehicle provided with a hybrid drive device that is an object of implementing the engine start method of the present invention. This hybrid vehicle has front wheels 1L, 1R and rear wheels 2L, 2R on the left and right sides of the vehicle body, the front wheels 1L, 1R are driven wheels, the rear wheels 2L, 2R are drive wheels, and the engine 3 is at the front of the vehicle body. The FR system to be installed.
That is, in the power train provided with the hybrid drive device of FIG. 1, the automatic transmission 4 is arranged in series behind the engine 3 in the vehicle longitudinal direction in the same manner as a normal rear wheel drive vehicle, and the crankshaft of the engine 3 (engine A motor / generator 7 is connected to a shaft 6 that transmits rotation from the output shaft 3a to the input shaft 5 of the automatic transmission 4. That is, the motor / generator 7 is disposed between the engine 3 and the automatic transmission 4.

The motor / generator 7 functions as a motor during driving traveling supplied with power from a battery (not shown), and transmits rotation and torque to the shaft 6. Further, it functions as a generator during regenerative travel driven by torque input to the shaft 6. In other words, negative rotation and negative torque are input to the shaft 6 during regenerative travel.
More specifically, an engine-side clutch 8 as an engine-side friction element is interposed between the motor / generator 7 and the engine 3 and more specifically between the shaft 6 and the engine crankshaft 3a. / The generators 7 are coupled so as to be separable.

More specifically, a transmission-side clutch 9 as a transmission-side friction element is interposed between the motor / generator 7 and the automatic transmission 4, more specifically between the shaft 6 and the transmission input shaft 5, and this transmission-side clutch 9 Thus, the automatic transmission 4 and the motor / generator 7 are detachably coupled.
These clutches 8 and 9 are each supplied with hydraulic pressure from a hydraulic circuit composed of a control valve (not shown), and the hydraulic circuit variably controls the hydraulic pressure to transmit torque and the rotational speed as it is, and to be controlled. When a torque exceeding the engagement capacity is transmitted, a slip engagement state in which the slip rotation is performed and a complete release state in which no torque is transmitted are executed. The fastening capacity can be continuously changed according to the supplied hydraulic pressure.

  The automatic transmission 4 is a known one such as a stepped automatic transmission having a torque converter or a belt-type continuously variable transmission. The automatic transmission 4 shifts the rotation from the transmission input shaft 5 at a gear ratio corresponding to the selected shift speed and directs it to the transmission output shaft 12, and the output rotation from this shaft 12 includes the propeller shaft 13, the differential The left and right rear wheels 2L and 2R are sequentially passed through the gear device 14 and the left and right drive shafts 15L and 15R, and are used to drive the vehicle.

  The power train of the hybrid vehicle configured as described above releases the engine-side clutch (engine-side friction element) 8 and shifts when an electric travel (EV travel) mode used when starting from a stationary state is required. The machine-side clutch (transmission-side friction element) 9 is engaged to set the automatic transmission 4 to the forward gear selection state.

  When the motor / generator 7 is driven in this state, only the output rotation from the motor / generator 7 reaches the transmission input shaft 5, and the automatic transmission 4 selects the forward shift while the rotation to the input shaft 5 is selected. The vehicle is driven by a motor / generator by shifting the speed according to the speed and sequentially passing the propeller shaft 13, the differential gear device 14 and the left and right drive shafts 15L, 15R from the transmission output shaft 12 to the left and right rear wheels 2L, 2R. Only 7 can be used for electric running (EV running). While the engine side clutch (engine side friction element) 8 is released, the engine 3 is stopped because the output of the engine 3 is not used.

When a hybrid driving (HEV driving) mode used for high-speed driving or heavy load driving is required, the engine-side clutch (engine-side friction element) 8 is engaged and the transmission-side clutch (transmission-side friction element) ) Fasten 9 to set the automatic transmission 4 to the forward gear selection state.
In this state, both the output rotation from the engine 3 and the output rotation from the motor / generator 7 reach the transmission input shaft 5, and the automatic transmission 4 moves the rotation from the input shaft 5 to the selected forward movement. By shifting with a gear ratio according to the speed stage, sequentially passing the propeller shaft 13, the differential gear device 14 and the left and right drive shafts 15L, 15R from the transmission output shaft 12 to the left and right rear wheels 2L, 2R, The vehicle can be hybrid traveled (HEV travel) by both the engine 3 and the motor / generator 7.

  In such HEV traveling, when energy is excessive to operate the engine with optimum fuel consumption, the surplus energy is converted into electric power by driving the motor / generator 7 as a generator by this surplus energy, and this generated electric power is converted into electric power. By accumulating power to be used for driving the motor of the motor / generator 7, the fuel efficiency of the engine 3 can be improved.

  When the hybrid vehicle of this embodiment travels in the electric travel (EV travel) mode, if the hybrid travel (HEV travel) mode is requested, the engine 3 needs to be started. Therefore, in the present embodiment, the process shown in the flowchart of FIG. 2 is performed, the clutches 8 and 9 to be controlled are slip-engaged, the output of the motor / generator 7 is controlled, and the engine 3 is started.

  The process of FIG. 2 is repeatedly executed by a scheduled interruption, for example, every 10 msec. First, in step S1, a control unit (not shown) of the hybrid vehicle commands to switch from the EV driving mode to the HEV driving mode. It is determined whether or not a request for starting the stopped engine 3 has occurred.

If it is determined that there is no engine start request (No), the process returns to step S1, and the presence or absence of the engine start request is continuously monitored.
If it is determined that an engine start request has been made (Yes), the process proceeds to step S2, and the engagement capacity of the transmission side clutch 9 is controlled. Specifically, the hydraulic pressure supplied to the piston and cylinder of the transmission-side clutch 9 is adjusted so that the torque transmitted by the transmission-side clutch 9 becomes the clutch engagement capacity during traveling in the conventional EV driving mode. Press. Further, the engagement capacity of the engine side clutch 8 is slightly increased from zero. This is to quickly shift to the engine start described later.

In the next step S3, it is determined whether or not differential rotation has occurred in the transmission-side clutch 9, that is, whether or not slip-engagement is being performed because the transmission-side clutch 9 is not completely engaged.
If no differential rotation has occurred in the transmission-side clutch 9 (No), the process proceeds to step S4, and this hydraulic pressure is reduced to the pressure-reducing side so as to reduce the engagement capacity of the transmission-side clutch 9 transmitted in step S2. Adjust pressure. By this slip engagement, the engagement capacity of the transmission-side clutch 9 is approximately matched to the torque required for traveling, and prepared for engine start to be described later.
If the transmission side clutch 9 is slipping (Yes), the process proceeds to step S5, and the rotational speed control of the motor / generator 7 is performed. Specifically, control is performed so that the motor / generator 7 outputs at least the engagement capacity of the transmission-side clutch 9 in step S2 or S4, and the rotational speed of the motor / generator 7 is slightly increased.

  The engagement capacity of the transmission-side clutch 9 here refers to output torque transmitted from the motor / generator 7 to the automatic transmission 4, and the motor / generator in which the shaft 6 is driven by the transmission input shaft 5. During the regenerative running of 7, this output torque becomes a negative value.

  In the next step S6, the number of rotations of the shaft 6 and the number of rotations of the transmission input shaft 5 are detected, and the difference between them is obtained, and the absolute value of the obtained difference rotation number of the transmission side clutch 9 is determined in advance. It is determined whether or not it substantially coincides with the predetermined value α. This predetermined value α is a differential rotational speed at which judder which is an unpleasant minute vibration does not occur. The predetermined value α is determined by the characteristics of the friction material of the transmission side clutch 9 and the inertia of the motor / generator 7. That is, this value is unique to the hybrid drive apparatus of the embodiment shown in FIG.

When the rotational speed difference of the transmission side clutch 9 is not the predetermined value α in step S6 (No), the process returns to step S5, and the rotational speed of the motor / generator 7 is controlled so as to be the predetermined value.
When the rotational speed difference of the transmission side clutch 9 is the predetermined value α (Yes), the process proceeds to step S7, and the capacity control of the engine side clutch 8 is performed. Specifically, the cranking torque (torque required for engine start) necessary for starting the stopped engine 3 is stored in advance, and the engine side clutch 8 is set so that the required engine start torque reaches the clutch engagement capacity. The hydraulic pressure supplied to the pistons and cylinders is increased. As a result, the crankshaft 3a of the engine 3 is rotated using the shaft 6 (cranking).

  In the next step S8, the rotational speed of the shaft 6 of the motor / generator 7 is detected, and it is determined whether or not the detected rotational speed of the motor / generator 7 is drawn by cranking. Specifically, the rotational speed of the motor / generator 7 is monitored, and if the reduction (reduction rate) of the rotational speed per unit time is equal to or greater than a predetermined value, the motor / generator 7 It is determined that the rotational speed has been drawn by cranking (Yes).

Alternatively, the target rotational speed of the motor / generator 7 at the time of the processing of this step S8 is read, and if the actual rotational speed of the motor / generator 7 is lower than the target rotational speed by a predetermined value, for example, 50 [rpm] or more, It is determined that the rotational speed of the generator 7 has been pulled in by cranking (Yes).
Here, the target rotational speed of the motor / generator 7 is a vehicle speed during which a control unit (not shown) of the hybrid drive device is traveling, a gear ratio determined by a selected gear stage of the automatic transmission 4 and the differential gear device 14. This means the number of revolutions determined from the accelerator opening and the like input to the accelerator operator by the driver. This target rotational speed substantially coincides with the rotational speed at the time of determining Yes in step S6 as long as the vehicle speed does not change rapidly.

If it is determined in step S8 that the detected rotational speed of the motor / generator 7 has not been drawn (No), the process returns to step S7. In step S7, the engagement capacity of the engine side clutch 8 is continuously increased. This is because the hydraulic pressure does not increase sufficiently in the previous processing of step S7, and the cranking torque is insufficient.
On the other hand, if it is determined in step S8 that the detected rotational speed of the motor / generator 7 is being pulled (Yes), the engine side clutch 8 is transmitting the cranking torque, and the process proceeds to step S9.

  In the next step S9, the torque of the motor / generator 7 is increased so as to compensate for the transmitted cranking torque. Thus, even when the transmission side clutch 9 is being cranked, it is possible to transmit a torque equivalent to the torque transmitted from the motor / generator 7 to the automatic transmission 4 before cranking.

  In the next step S10, the torque transmitted by the engine side clutch 8 is obtained by calculation or estimation, and it is determined whether or not the obtained engine side clutch transmission torque is larger than the engine start required torque. When the engine side clutch transmission torque is equal to or lower than the engine start required torque (No), the cranking torque currently being transmitted by the engine side clutch 8 is not sufficient to start the engine 3. Therefore, the process proceeds to step S11, where the engagement capacity of the engine side clutch 8 is controlled to be increased to increase the cranking torque, and the engine 3 can be started.

  In step S11, the rotational speed of the motor / generator 7 is read, and the engagement capacity of the engine side clutch 8 is increased by a predetermined value. Then, the process returns to step S10, and it is determined again whether or not the engine side clutch transmission torque is larger than the engine start required torque. Thereafter, steps S10 to S11 are repeated until the engine-side clutch transmission torque reaches the engine start required torque.

In the process of step S11, the actual rotational speed of the motor / generator 7 at the time of the process is read and stored. Then, in the repeated processing at regular intervals between steps S10 to S11, the previous value of the actual rotational speed of the motor / generator 7 is compared with the current value, and the current value is a predetermined threshold value or more than the previous value. Judge whether it is large or not.
When the actual rotational speed of the current value of the motor / generator 7 is larger than the actual rotational speed of the previous value by a threshold value or more, it can be determined that the increase amount (increase rate) per unit time of the rotational speed of the motor / generator 7 is large. .
Therefore, when the increase rate is larger than a predetermined threshold, the engagement capacity of the engine side clutch 8 is increased at a predetermined speed. As a result, it is possible to effectively prevent the motor / generator 7 from over-rotating and blowing up in the engine.

  Alternatively, in the process of step S11, the target rotational speed of the motor / generator 7 at the time of the processing is read, and the actual rotational speed of the motor / generator 7 is a predetermined threshold value, for example, 50 [rpm] or more than the target rotational speed It may be determined whether or not the increase rate is large depending on whether or not it is high.

  If the engine-side clutch transmission torque becomes larger than the engine start required torque in step S10 by the control between steps S9 to S11, the engine 3 can be started. Therefore, the process proceeds to step S12. In step S12, conditions for starting the engine 3, such as starting fuel injection of the engine 3, are prepared.

  When the engine 3 is self-supporting in step S12, in the next step S13, a command is output to reduce the engagement capacity of the engine side clutch 8 to a predetermined value Tslip. Here, “decrease” means that the engagement capacity of the engine-side clutch 8 is temporarily reduced and held at Tslip, and then the engagement capacity of the engine-side clutch 8 is increased from Tslip to be described later. Thus, the engine side clutch 8 is completely engaged. This is to shift to the HEV driving mode.

  Since the peak of the output torque (initial explosion torque) appears at the start of the engine 3, the initial explosion torque rotates the shaft 6 by reducing the engagement capacity of the engine side clutch 8 to Tslip in step S13. Thus, it is possible to prevent the rotation speed of the motor / generator 7 from increasing.

In the next step S14, engagement of the transmission side clutch 9 is started.
In other words, since the command to decrease the engagement capacity of the engine side clutch 8 is output in the above step S13, the engagement capacity of the engine side clutch 8 decreases with the execution of step S14, and the transmission side clutch 9 is engaged. The capacity is larger than the engagement capacity Tslip of the engine side clutch 8. Then, it is assumed that the engagement capacity of the transmission side clutch 9 is made larger than the engagement capacity of the engine side clutch 8 through the engagement control of the clutches 8 and 9 after step S14.

In the next step S15, a differential rotational speed of the engine side clutch 8 is obtained, and it is determined whether or not the obtained differential rotational speed is less than a predetermined value γ. The differential rotational speed of the engine side clutch 8 refers to the difference between the rotational speed of the shaft 6 and the rotational speed of the crankshaft 3a. In addition, the predetermined value γ is set to a slight value to avoid a shock from the transmission input shaft 5 toward the drive wheels 2L and 2R during the complete engagement operation of the engine side clutch 8 described later.
When the differential rotational speed of the transmission side clutch 9 is equal to or greater than the predetermined value γ (No), the process proceeds to step S16, the engagement capacity of the engine side clutch 8 is increased, and the differential rotational speed of the engine side clutch 8 is less than the predetermined value γ. To decrease.
When the differential rotation speed of the transmission side clutch 9 is less than the predetermined value γ (Yes), the process proceeds to step S17, and the engine side clutch 8 is completely engaged.
When the clutch 8 is completely engaged, this control is terminated and the mode is shifted to the HEV traveling mode.

  The above processing of the present embodiment includes the control for starting the engine 3 without the motor / generator 7 over-rotating, and the control for shifting to the HEV travel mode using the engine 3 that is self-supported by the engine start control. Is a combination. It is also possible to carry out the former control alone.

  Next, the operation when the engine starting method according to this embodiment is executed will be described, taking as an example the case where the vehicle having the hybrid drive device shown in FIG.

  FIG. 3 shows the state of the engine 3 when the engine-side clutch 8 is completely released, the transmission-side clutch 9 is completely engaged, and the stopped engine 3 is started while the motor / generator 7 is driven to travel. 4 is a time chart showing comparison of torque, rotational speed, and engagement capacity of a crankshaft 3a, a shaft 6 of a motor / generator 7, and a transmission input shaft 5 of an automatic transmission 4.

  When the motor / generator 7 is driven as a motor, before the instant t1, the engine-side clutch 8 is completely released and its engagement capacity is set to 0, and the transmission-side clutch 9 is fully engaged and its engagement capacity is maximized. .

  If there is a request for engine start at instant t1 (Yes in step S1), the engagement capacity of transmission side clutch 9 is reduced after instant t1 (step S2), and from this moment instant t1 to instant t5, the transmission side clutch 9 is controlled to a fastening capacity necessary and sufficient for driving. 3, the driving force of the wheels 2L and 2R (traveling required torque) is constant, so that the engagement capacity of the transmission-side clutch 9 from around the instant t1 to the instant t5 is also constant. . Further, after the instant t1, the engine side clutch 8 is also slip-engaged to prepare for the rotation of the crankshaft 3a described later.

Since the rotational speed of the shaft 6 is larger than the rotational speed of the transmission input shaft 5 at the instant t2, if the slip engagement of the transmission side clutch 9 is confirmed here (Yes in step S3), the motor / generator is generated after the instant t2. The output torque and the rotational speed of 7 are controlled for driving and cranking (steps S5 to S6). Therefore, the output torque of the motor / generator 7 from the instant t2 to t7 is larger than the output torque before the instant t2.
When the differential rotational speed of the transmission side clutch 9 reaches the predetermined value α at the instant t3 (Yes in step S6), the engagement capacity of the engine side clutch 8 increases as shown by (1) in FIG. 3 after the instant t3. And the crankshaft 3a of the engine 3 is rotated (step S7).

  When cranking is executed by the above rotation after the instant t3, the rotation speed of the motor / generator 7 is drawn between the instants t3 and t4 at the beginning of the cranking as shown in (2) of FIG. Decrease (Yes in step S8). Immediately thereafter, the torque of the motor / generator 7 is increased as shown in (3) of FIG. 3 (step S9), and the rotational speed of the motor / generator 7 drawn in (2) is recovered. This increase compensates for cranking torque.

  Even after picking up the motor / generator 7, the rotational speed of the motor / generator 7 may continue to increase, resulting in excessive rotation as indicated by the broken line in (4). In this case, the engagement capacity of the engine side clutch 8 is increased with a predetermined time change rate as indicated by the broken line in (5) (step s11). This prevents the motor / generator 7 from over-rotating.

  As a result of the cranking, the rotational speed of the crankshaft 3a rises at a substantially constant gradient from approximately instant t4 to instant t5. By adjusting the start condition of the engine 3 at the instant t5 (step S12), the engine 3 starts to be independent after the instant t5, and the engine start that is the target of this control is achieved.

  When the engine 3 is self-supporting, the engine torque at the start of self-sustaining increases rapidly, and the initial explosion torque appears between approximately instants t5 and t6. The peak (maximum) of the initial explosion torque is at the instant between the instant t5 and the instant t6. As shown in (6) of Fig. 3, near the instant t5 before the initial explosion torque becomes maximum. The engagement capacity of the engine side clutch 8 is reduced to Tslip (step S13).

  In order to increase the engagement capacity of the transmission-side clutch 9 while decreasing the engagement capacity of the engine-side clutch 8 to Tslip after the instant t5 (step S14), the rotational speed of the motor / generator 7 is rotated by the crankshaft 3a. Will not increase. Further, the rotational speed of the motor / generator 7 gradually decreases so as to approach the rotational speed of the transmission input shaft 5 after the instant t5. Then, the transmission-side clutch 9 is completely engaged at a certain instant between instants t5 and t6, and the rotational speed of the motor / generator 7 coincides with the rotational speed of the transmission input shaft 5.

  On the other hand, the rotational speed of the engine 3 (the rotational speed of the crankshaft 3a) overshoots over the rotational speed of the transmission input shaft 5 at an instant between the instants t5 and t6 due to the peak of the initial explosion torque.

  The initial explosion torque reaches the maximum value at a certain instant between instant t5 and t6. After the maximum value occurs, the initial explosion torque decreases, and the initial explosion torque ends shortly before the instant t6. When the initial explosion torque of the engine ends, the torque of the engine 3 stabilizes at a value corresponding to the accelerator opening after substantially the instant t6.

As described above, in order to reduce the engagement capacity of the engine side clutch 8 to Tslip near the instant t5 before the peak of the initial explosion torque (step S13), even if the engine initial explosion torque occurs after the instant t5, the shaft 6 is not excessively rotated, and the transmission input shaft 5 is also rotated and does not increase. The engagement capacity of the engine side clutch 8 is held at Tslip until the differential rotation speed of the engine side clutch 8 reaches a predetermined value γ.
When the differential rotational speed of the engine side clutch 8 reaches the predetermined value γ at the instant t6 (Yes in step S15), the engagement capacity of the engine side clutch 8 is increased (step S16). By completely engaging the engine side clutch 8 (step S17), the rotational speed of the motor / generator 7 coincides with the rotational speed of the transmission input shaft 5 at the instant t7.

By the way, in the engine starting method of the present embodiment, when starting the engine 3 during driving traveling (EV traveling) of only the motor / generator 7, the engagement capacity of the engine side clutch 8 is increased in step S7 in FIG. Start engine 3 rotation (cranking). When the pulling of the motor / generator 7 is detected by this rotation in step S8, the cranking torque equivalent to the engagement capacity of the engine side clutch 8 to be controlled in step S7 is compensated in the motor / generator 7 in step S9. From
There is no need to increase the rotational speed of the motor in advance before cranking starts as in the prior art, and it is possible to solve the problem that the over-rotation sound of the motor gives the passenger a sense of incongruity.

  Further, in step S9, in order to control the output of the motor / generator 7 to be increased so as to compensate for the cranking torque, the engine start method of the present invention is used while the motor / generator 7 is driven and traveling in the EV traveling mode. Even in this case, stable driving can be realized without reducing the driving force of the driving wheels 2R and 2L during the driving.

In the present embodiment, the pull-in is detected in step S8. Specifically, when the reduction amount (reduction rate) per unit time in the rotation speed of the motor / generator 7 is less than a predetermined value, or when the actual rotation speed of the motor / generator 7 is smaller than the target rotation speed by a predetermined value or more Because it is determined that
Before the output torque of the motor // generator 7 decreases, it is possible to compensate for the engine start required torque, avoiding any trouble in driving driving of the vehicle, and gently accelerating as shown in FIG. There is no loss of driving.

  In this embodiment, in step S11, when the amount of increase in the rotation speed of the motor / generator 7 per unit time is equal to or greater than a predetermined threshold value, or the rotation speed of the motor / generator 7 is higher than the target rotation speed. 3, the engagement capacity of the engine-side clutch 8 is increased with a predetermined rate of change of time as shown by (5) in FIG. 3, so that over-rotation of the motor / generator 7 is prevented in advance. be able to. Therefore, the discomfort felt by the passenger, which is the problem to be solved by the present invention, can be effectively eliminated.

Further, in this embodiment, when the engine 3 becomes independent at the instant t5 in steps S7 to S11, the initial explosion torque of the engine 3 appears from the instant t5 to slightly before the instant t6. At the instant t5 before the initial explosion torque becomes maximum, the engagement capacity of the engine side clutch 8 is reduced as shown in FIG.
It is possible to prevent the initial explosion torque from increasing the rotational speed of the motor / generator 7. Therefore, it is possible to effectively reduce over-rotation of the motor / generator 7 which is a problem to be solved by the present invention.

Further, in this embodiment, after the engine becomes independent in steps S7 to S11, the torque of the engine 3 is stabilized at a value corresponding to the accelerator opening. Then, the engagement capacity of the engine side clutch 8 is controlled so that the difference between the rotation speed of the engine 3 and the rotation speed of the motor / generator 7 is within a predetermined value γ under the engine torque stabilization period after the substantially instant t6.
And at the instant t6, when the differential rotation is within the predetermined value γ, the engine side clutch 8 is completely engaged,
As shown in FIG. 3, even if the engine is started while driving while driving slowly, there is no problem that the driving force of the driving wheels 2L and 2R is temporarily reduced to impair running stability.

  The above description is merely an example of the present invention, and the present invention can be variously modified without departing from the spirit of the present invention.

It is a schematic plan view showing a power train of a rear wheel drive vehicle provided with a hybrid drive device to which the idea of the present invention can be applied. It is a flowchart which shows the control program for performing the engine starting method of a present Example. It is an operation | movement time chart in the case of performing the engine starting method of the Example during the driving driving | running | working of a motor / generator.

Explanation of symbols

1L, 1R left and right front wheels
2L, 2R left and right rear wheels
3 Engine (Internal combustion engine)
3a crankshaft
4 Automatic transmission
5 Transmission input shaft
6 Motor / generator rotary shaft
7 Motor / generator
8 Engine side clutch (engine side friction element)
9 Transmission side clutch (Transmission side friction element)
12 Transmission output shaft
13 Propeller shaft
14 Differential gear unit
15L, 15R left and right drive shaft

Claims (5)

The engine output shaft is drive-coupled to the transmission input shaft, and a motor / generator is provided between the engine and the transmission,
In a vehicle hybrid drive device having an engine-side friction element that releasably couples an engine and a motor / generator, and a transmission-side friction element that releasably couples a motor / generator and a transmission,
In starting the engine while the vehicle is running with the engine side friction element released and the transmission side friction element fastened,
Increasing the fastening capacity of the engine side friction element and rotating the engine,
A hybrid having pull-in detection means for detecting pull-in of the rotation speed of the motor / generator due to the rotation, and causing the motor / generator to compensate for a torque equivalent to the fastening capacity of the engine-side friction element at the time of detection. The engine starting method of a drive device. The method of starting an engine for a hybrid drive device according to claim 1,
The pull-in detection means performs the pull-in when the reduction amount per unit time in the rotation speed of the motor / generator is a predetermined value or less, or when the rotation speed of the motor / generator is smaller than the target rotation speed by a predetermined value or more. A method for starting an engine of a hybrid drive device, comprising: detecting the engine. The engine starting method of the hybrid drive device according to claim 1 or 2,
During the compensation, when the increase amount per unit time in the rotation speed of the motor / generator is a predetermined value or more, or when the rotation speed of the motor / generator is larger than the target rotation speed by a predetermined value or more, the engine side friction element An engine starting method for a hybrid drive apparatus, wherein the fastening capacity of the hybrid drive apparatus is increased with a predetermined rate of time change. In the engine starting method of the hybrid drive device according to any one of claims 1 to 3,
When the engine is self-supporting by the rotation, the fastening capacity of the engine-side friction element is reduced before the initial explosion torque, which is the engine torque at the start of the self-sustainment, is maximized. . In the engine starting method of the hybrid drive device according to any one of claims 1 to 4,
After the engine is self-supporting by the rotation, the engine torque is stabilized at a value corresponding to the accelerator opening,
Under this engine torque stabilization period, the engagement capacity of the engine side friction element is controlled so that the difference between the engine speed and the motor / generator speed is within a predetermined value.
An engine starting method for a hybrid drive device, wherein the engine side friction element is completely fastened within the predetermined value.

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