WO2015052760A1

WO2015052760A1 - Device for controlling hybrid vehicle

Info

Publication number: WO2015052760A1
Application number: PCT/JP2013/077290
Authority: WO
Inventors: 良祐伊東; 孝夫安藤; 大城岩佐
Original assignee: 日産自動車株式会社
Priority date: 2013-10-08
Filing date: 2013-10-08
Publication date: 2015-04-16

Abstract

Provided is a device that is for controlling a hybrid vehicle and that can effect increased fuel economy while suppressing engine start shock and changes in vehicle deceleration during an engine starting request during coasting/regenerating driving. An engine starting control means (fig. 3), which performs engine starting control with a motor/generator (4) as an engine starting motor when an engine starting request has arisen when in a coasting state during coasting/regenerating driving in an EV mode, is configured having: a second clutch control unit that causes the slip engagement of a second clutch (5) and that maintains the engagement capacity of the second clutch at an amount at which deceleration arises as a result of the regenerating torque of the motor/generator (4); a motor rotational frequency control unit that reduces the rotational frequency of the motor/generator (4) to less than a second clutch output rotational frequency; and a motoring control unit that causes a first clutch (3) to be engaged or slip engaged and causes the engine (2) to be in a motoring state by means of the motor/generator (4).

Description

Control device for hybrid vehicle

The present invention relates to a hybrid vehicle control apparatus that starts an engine by a motor generator in a hybrid vehicle having an engine and a motor generator.

Conventionally, there is known a hybrid vehicle in which a dual clutch transmission having a pair of clutches is interposed between an engine and driving wheels, and a motor is connected to one torque transmission path in the dual clutch transmission. In this hybrid vehicle, when both the pair of clutches are released and the negative pressure of the booster falls below a threshold during deceleration in the electric vehicle mode in which the vehicle travels only with the driving force of the motor, at least one of the pair of clutches. 2. Description of the Related Art A hybrid vehicle control device that engages one side or slips and starts an engine is known (see, for example, Patent Document 1).

JP 2009-137405 A

By the way, in the conventional hybrid vehicle control apparatus, it is unknown about the engagement capacity of the clutch that is engaged or slip-engaged when the engine is started. For this reason, it has been difficult to absorb changes in vehicle deceleration and start shocks when the engine is started.
In addition, if the engine combustion state is set in spite of obtaining the booster negative pressure, there is a problem that the fuel consumption is deteriorated.

The present invention has been made paying attention to the above problems, and controls a hybrid vehicle capable of improving fuel efficiency while suppressing changes in vehicle deceleration and engine start shocks at the time of engine start request during coast regenerative operation. An object is to provide an apparatus.

In order to achieve the above object, a control apparatus for a hybrid vehicle according to the present invention includes an engine, a motor generator, a first clutch interposed between the engine and the motor generator, a drive for the motor generator, and a drive system. A second clutch interposed between the wheels, and during coast regeneration operation by the motor generator in the electric vehicle mode in which the first clutch is disengaged and the second clutch is engaged to travel. An engine start control means is provided for performing engine start control using the motor generator as an engine start motor when an engine start request is generated.
The engine start control means includes a second clutch control unit, a motor rotation number control unit, and a motoring control unit.
The second clutch control unit slip-engages the second clutch, and maintains the second clutch engagement capacity at this time at an amount at which a predetermined deceleration due to the regenerative torque of the motor generator is generated.
The motor rotation speed control unit reduces the rotation speed of the motor generator to be smaller than the second clutch output rotation speed.
The motoring control unit engages or slips the first clutch and puts the motor into a motoring state in which the engine is rotated without fuel injection.

Therefore, in the hybrid vehicle control device of the present invention, when the engine start request is made, the second clutch control unit slip-engages the second clutch, so that the motor torque fluctuation accompanying the engine start control is transmitted to the drive wheels. It is possible to prevent and suppress engine start shock.
Further, the second clutch control unit maintains the second clutch engagement capacity at the time of slip engagement of the second clutch at an amount that generates a predetermined deceleration due to the regenerative torque of the motor generator. For this reason, the vehicle deceleration during the regenerative operation by the motor generator is maintained, and changes in the vehicle deceleration can be absorbed.
Then, the motor rotation speed control unit makes the rotation speed of the motor generator smaller than the second clutch output rotation speed, so that the regenerative state can be reliably continued, the motor torque can be increased, and the engine can be quickly motored. Can be in a state.
Further, in the motoring control unit, the motor generator is brought into a motoring state in which the engine is rotated without fuel injection by engaging or slip-engaging the first clutch. Here, the engine start request is generated in the coast state. That is, it is necessary for the engine to rotate (cranking), but the engine combustion torque is not required. Therefore, by rotating the motor generator without rotating the engine, the engine can be rotated while suppressing excessive fuel consumption, and deterioration of fuel consumption can be prevented.

1 is an overall system diagram illustrating an FF hybrid vehicle to which a control device according to a first embodiment is applied. It is a figure which shows an example of the driving mode switching map in FF hybrid vehicle of Example 1. FIG. It is a flowchart which shows the flow of the engine starting control process (engine starting control means) performed with a hybrid control module. In the control device of the first embodiment, the accelerator opening, vehicle G, CL2 torque command, CL1 hydraulic pressure command, ENG rotation speed, MG rotation speed, PRI rotation speed when an engine start request is generated due to a system request during coast regeneration operation. It is a time chart which shows each characteristic.

Hereinafter, the best mode for realizing the control apparatus for a hybrid vehicle of the present invention will be described based on Example 1 shown in the drawings.

Example 1
First, the configuration of the hybrid vehicle control device according to the first embodiment will be described by dividing it into “the overall system configuration of the FF hybrid vehicle” and “the detailed configuration of the engine start control process”.

[Overall system configuration of FF hybrid vehicle]
FIG. 1 is an overall system diagram illustrating an FF hybrid vehicle to which the control device of the first embodiment is applied. The overall system configuration of the FF hybrid vehicle to which the hybrid vehicle control device of the first embodiment is applied will be described below with reference to FIG.

As shown in FIG. 1, the drive system of the FF hybrid vehicle (an example of a hybrid vehicle) includes a starter motor 1, a horizontally mounted engine 2 (abbreviated as “ENG”), and a first clutch 3 (abbreviated as “CL1”). , A motor generator 4 (abbreviated as “MG”), a second clutch 5 (abbreviated as “CL2”), and a belt type continuously variable transmission 6 (abbreviated as “CVT”). The output shaft of the belt-type continuously variable transmission 6 is drivingly connected to the left and right

front wheels

10L and 10R, which are drive wheels, via a final reduction gear train 7, a differential gear 8, and left and

right drive shafts

9L and 9R. The left and right

rear wheels

11L and 11R are driven wheels.

The starter motor 1 is a cranking motor that has a gear that meshes with an engine starting gear provided on a crankshaft of the horizontal engine 2 and that rotates the crankshaft when the engine is started.

The horizontal engine 2 is an engine disposed in the front room with the crankshaft direction as the vehicle width direction, and serves as a drive source for the FF hybrid vehicle. The horizontal engine 2 includes an electric water pump 12 and a crankshaft rotation sensor 13 that detects reverse rotation of the horizontal engine 2. In addition, a compressor (not shown) for an indoor air conditioner is driven by the horizontal engine 2. Further, the intake negative pressure of the horizontally placed engine 2 is introduced into a negative pressure booster (not shown).

The first clutch 3 is a normally open dry multi-plate friction clutch that is hydraulically operated and is interposed between the horizontal engine 2 and the motor generator 4, and is fully engaged / slip engaged / released by the first clutch oil pressure. Be controlled.

The motor generator 4 is a three-phase AC permanent magnet synchronous motor connected to the transverse engine 2 via the first clutch 3 and serves as a drive source for the FF hybrid vehicle. When a positive torque (drive torque) command is output from the motor controller 83 to the inverter 26, the motor generator 4 performs a drive operation to generate drive torque using the discharge power from the high-power battery 21, The

front wheels

10L, 10R are driven (powering). On the other hand, when a negative torque (power generation torque) command is output from the motor controller 83 to the inverter 26, a power generation operation is performed to convert rotational energy from the left and right

front wheels

10L, 10R into electric energy, and the generated power is The charging power of the high-power battery 21 is used (regeneration).
The motor generator 4 and the inverter 26 are connected via an AC harness 27.

The second clutch 5 is a normally closed wet multi-plate friction clutch by hydraulic operation that is interposed between the motor generator 4 and the left and right

front wheels

10L, 10R as drive wheels, and is completely engaged by the second clutch hydraulic pressure. / Slip fastening / release is controlled. The second clutch 5 of the first embodiment uses the forward clutch 5a and the reverse brake 5b provided in the forward / reverse switching mechanism of the belt-type continuously variable transmission 6 using planetary gears. That is, the forward clutch 5 a is the second clutch 5 during forward travel, and the reverse brake 5 b is the second clutch 5 during reverse travel.

The belt type continuously variable transmission 6 is a transmission that obtains a continuously variable transmission ratio by changing the belt winding diameter by the transmission hydraulic pressure to the primary oil chamber and the secondary oil chamber. The belt type continuously variable transmission 6 includes a main oil pump 14 (mechanical drive), a sub oil pump 15 (motor drive), and a line pressure PL generated by adjusting pump discharge pressure from the main oil pump 14. And a control valve unit (not shown) that generates the first and second clutch hydraulic pressures and the transmission hydraulic pressure with the pressure as the original pressure. The main oil pump 14 is rotationally driven by the motor shaft (= transmission input shaft) of the motor generator 4. The sub oil pump 15 is mainly used as an auxiliary pump for producing lubricating cooling oil.

In the FF hybrid vehicle, the first clutch 3, the motor generator 4 and the second clutch 5 constitute a drive system for one motor and two clutches, and “EV mode” is the main travel mode (drive mode) by this drive system. And “HEV mode” and “WSC mode”.
The “EV mode” is an electric vehicle mode in which the first clutch 3 is disengaged and the second clutch 5 is engaged and only the motor generator 4 is used as a drive source. That's it. In this “EV mode”, the running mode in which the motor generator 4 regenerates and coasts decelerates with the accelerator off (accelerator release state) is referred to as “coast regenerative operation” or “sailing mode running”. At this time, it does not matter whether or not the brake is operated.
The “HEV mode” is a hybrid vehicle mode in which the first and second clutches 3 and 5 are engaged and the horizontal engine 2 and the motor generator 4 are used as driving sources. " When this “HEV mode” is subdivided according to how the motor generator 4 is used, the engine vehicle mode (0 torque command to the motor generator 4), the motor assist mode (positive torque command to the motor generator 4), the engine power generation mode (motor generator 4) Negative torque command).
In the “WSC mode”, the horizontal engine 2 is operated, the first clutch 3 is engaged, and the second clutch 5 is slip-engaged with a transmission torque capacity corresponding to the required driving force. This is an engine-use slip mode that travels while being included in the power source.
In this travel mode (driving mode), the operating point determined by the accelerator opening and the vehicle speed is determined by the position on the switching map shown in FIG. Furthermore, switching from the “EV mode” to the “HEV mode” (output of the engine start request) is also performed according to the system requirements listed below, regardless of the position of the operating point on the map of FIG.
・ When the battery charge capacity (battery SOC) falls below a certain value ・ When an operation request for the compressor for the indoor air conditioner is output ・ The negative pressure for braking in the negative pressure booster decreases and a negative pressure generation request is output When an engine diagnosis request is output

Note that the regenerative cooperative brake unit 16 shown in FIG. 1 is a device that controls the total braking torque in accordance with the regenerative operation in principle when the brake is operated. The regenerative cooperative brake unit 16 includes a brake pedal, a negative pressure booster that uses the intake negative pressure of the horizontally placed engine 2, and a master cylinder. Then, during the brake operation, cooperative control for the regenerative / hydraulic pressure is performed such that the amount of subtraction of the regenerative braking force from the required braking force based on the pedal operation amount is shared by the hydraulic braking force.

As shown in FIG. 1, the power system of the FF hybrid vehicle includes a high-power battery 21 as a motor generator power source and a 12V battery 22 as a 12V system load power source.

The high-power battery 21 is a secondary battery mounted as a power source for the motor generator 4, and for example, a lithium ion battery in which a cell module constituted by a large number of cells is set in a battery pack case is used. The high-power battery 21 has a built-in junction box in which relay circuits for supplying / cutting off / distributing high-power are integrated, and further includes a cooling fan unit 24 having a battery cooling function, a battery charging capacity (battery SOC) and a battery. And a lithium battery controller 86 for monitoring the temperature.

The high-power battery 21 and the motor generator 4 are connected through a DC harness 25, an inverter 26, and an AC harness 27. The inverter 26 is provided with a motor controller 83 that performs power running / regenerative control. That is, the inverter 26 converts the direct current from the DC harness 25 into the three-phase alternating current to the AC harness 27 during power running that drives the motor generator 4 by discharging the high-power battery 21. Further, the three-phase alternating current from the AC harness 27 is converted into direct current to the DC harness 25 during regeneration in which the high-power battery 21 is charged by power generation by the motor generator 4.

The 12V battery 22 is a secondary battery mounted as a power source for a 12V system load, which is an auxiliary machine. For example, a lead battery mounted in an engine vehicle or the like is used. The high voltage battery 21 and the 12V battery 22 are connected via a DC branch harness 25a, a DC / DC converter 37, and a battery harness 38. The DC / DC converter 37 converts a voltage of several hundred volts from the high-power battery 21 to 12V, and the charge amount of the 12V battery 22 is controlled by controlling the DC / DC converter 37 by the hybrid control module 81. Is configured to manage.

As shown in FIG. 1, the control system of the FF hybrid vehicle includes a hybrid control module 81 (abbreviation: “HCM”) as an integrated control means for properly managing the energy consumption of the entire vehicle. Control means connected to the hybrid control module 81 include an engine control module 82 (abbreviation: “ECM”), a motor controller 83 (abbreviation: “MC”), and a CVT control unit 84 (abbreviation: “CVTCU”). And a lithium battery controller 86 (abbreviation: “LBC”). These control means including the hybrid control module 81 are connected by a CAN communication line 90 (CAN is an abbreviation of “Controller Area Network”) so that bidirectional information can be exchanged.

The hybrid control module 81 performs various controls based on input information from each control means, an ignition switch 91, an accelerator opening sensor 92, a vehicle speed sensor 93, and the like. The engine control module 82 performs fuel injection control, ignition control, fuel cut control, and the like of the horizontally placed engine 2. The motor controller 83 performs power running control, regeneration control, and the like of the motor generator 4 by the inverter 26. The motor controller 83 receives output rotation speed information of the motor generator 4 from the MG rotation speed sensor 94. The CVT control unit 84 performs engagement hydraulic pressure control of the first clutch 3, engagement hydraulic pressure control of the second clutch 5, shift hydraulic pressure control of the belt type continuously variable transmission 6, and the like. The CVT control unit 84 receives transmission input rotation speed information (= second clutch output rotation speed information) from the transmission input rotation speed sensor 95. The lithium battery controller 86 manages the battery SOC, battery temperature, and the like of the high-power battery 21.

[Detailed configuration of engine start control processing]
FIG. 3 is a flowchart showing the flow of engine start control processing (engine start control means) executed by the hybrid control module. Hereinafter, each step of FIG. 3 showing the detailed configuration of the engine start control process will be described. This engine start control process is repeatedly executed during the “EV mode”.

In step S1, it is determined whether or not the current traveling mode (driving mode) is “coast regenerative operation”. If YES (coast regenerative operation), the process proceeds to step S2. If NO (other than coast regeneration), proceed to return.
Here, the determination of the coast regenerative operation is performed when the accelerator is in an OFF state while regenerating with the motor generator 4 in the “EV mode”.

In step S2, following the determination of “coast regenerative operation” in step S1, it is determined whether an engine start request due to a system request has occurred in the coast state. If YES (engine start requested by system request), the process proceeds to step S3. If NO (no engine start requested by system request), proceed to return.
This "engine request by system request" means that when a compressor operation request for an indoor air conditioner is output, the negative pressure for braking in the negative pressure booster decreases and a negative pressure generation request is output. When an engine diagnosis request is output. Further, when the engine start request is output, it is “coast state” and the accelerator is OFF. Therefore, there is no increase in required driving force. That is, it is necessary to rotate (crank) the horizontal engine 2 based on the engine start request, but no engine combustion torque is required.

In step S3, following the determination that there is an engine start request in response to the system request in step S2, a CL2 slip command for reducing the clutch engagement capacity (= second clutch torque) of the second clutch 5 and setting the slip engagement state is output. Then, the process proceeds to step S4.
Here, the second clutch engagement capacity (= second clutch torque) is an amount by which a deceleration equivalent to a predetermined deceleration acting on the vehicle due to the regenerative torque of the motor generator 4 during the coast regenerative operation is generated in the vehicle. Is set.

In step S4, following the output of the CL2 slip command in step S3, it is determined whether or not the clutch engagement capacity of the second clutch 5 is within a predetermined set range. If YES (the second clutch torque is within the set range), the process proceeds to step S5. If NO (the second clutch torque is outside the set range), step S4 is repeated.
Here, the fact that the second clutch torque is within the set range means that the actual second clutch torque is within a predetermined error range with respect to the second clutch torque (target value) set in step S3. It is in place. The second clutch torque is detected by a second clutch torque sensor (not shown).

In step S5, following the determination that the second clutch torque is within the set range in step S4, the CL1 hydraulic pressure command for setting the hydraulic pressure of the first clutch 3 to the standby hydraulic pressure, and the output rotational speed of the motor generator 4 are reduced. The MG rotational speed command for making it smaller than the 2-clutch output rotational speed is output, and the process proceeds to step S6.
As a result, the rotation speed of the motor generator 4 starts to be reduced. At this time, the motor rotation speed is gradually reduced with time.
The “second clutch output rotational speed” is the input rotational speed (PRI rotational speed) to the belt type continuously variable transmission 6 and is detected by the transmission input rotational speed sensor 95. Further, the “standby hydraulic pressure” is a hydraulic pressure that eliminates play of the hydraulic pressure of the first clutch 3, and is the state immediately before the first clutch 3 starts the engagement operation.

In step S6, following the output of the CL1 hydraulic pressure command and the MG rotational speed command in step S5, it is determined whether or not the rotational speed of the motor generator 4 to be made smaller than the second clutch output rotational speed has fallen below a preset determination threshold value. to decide. If YES (MG rotational speed <determination threshold), the process proceeds to step S7. If NO (MG rotational speed ≧ determination threshold), step S6 is repeated.
Here, the “determination threshold value” is set to a rotational speed at which the output torque from the motor generator 4 reaches the torque necessary for engine cranking.

In step S7, following the determination of MG rotation speed <determination threshold value in step S6, a CL1 hydraulic pressure command for changing the hydraulic pressure of the first clutch 3 to the cranking hydraulic pressure and a cranking command for the horizontal engine 2 are output. Proceed to S8.
As a result, the rotation of the motor generator 4 is transmitted to the horizontal engine 2 and the engine speed starts to increase.
Here, the “cranking hydraulic pressure” is a clutch engagement hydraulic pressure capable of transmitting a torque necessary for engine cranking.

In step S8, following the output of the CL1 hydraulic pressure command and the cranking command in step S7, it is determined whether or not the rotational speed of the horizontally placed engine 2 is equal to or higher than a preset engine startable rotational speed. If YES (ENG rotational speed ≧ engine startable rotational speed), the process proceeds to step S9. If NO (ENG engine speed <engine startable engine speed), step S8 is repeated.
Here, the “engine startable rotation speed” is a rotation speed at which the horizontally mounted engine 2 can operate independently by injecting and igniting a certain amount of air and fuel. Here, the rotation speed is set lower than the determination threshold value set in step S6.

In step S9, following the determination that ENG rotational speed ≧ engine startable rotational speed in step S8, a CL1 hydraulic pressure command for changing the hydraulic pressure of the first clutch 3 to the engagement hydraulic pressure is output, and the process proceeds to step S10.

In step S10, following the output of the CL1 hydraulic pressure command in step S9, it is determined whether or not the first clutch 3 is completely engaged. If YES (CL1 engagement complete), the process proceeds to step S11. If NO (CL1 is not fastened), step S10 is repeated.
Here, the engagement determination of the first clutch 3 is performed based on the clutch stroke of the first clutch. At this time, air / fuel injection and ignition operations are not performed for the horizontally placed engine 2. That is, the horizontally placed engine 2 is in a motoring state that rotates with the rotation of the motor generator 4 and rotates without fuel injection.

In step S11, following the determination that the CL1 engagement is completed in step S10, a CL2 engagement command for engaging the second clutch 5 is output, and the process proceeds to step S12.

In step S12, following the output of the CL2 engagement command in step S11, it is determined whether or not the second clutch 5 is completely engaged. If YES (CL2 conclusion), proceed to return. If NO (CL2 not fastened), step S12 is repeated.
Here, the engagement determination of the second clutch 5 is a predetermined value at which the differential rotation in the second clutch 5 becomes zero and the clutch engagement capacity (second clutch torque) in the second clutch 5 can be determined to be the engagement torque. To do that.

Next, the engine start control action in the control apparatus for the FF hybrid vehicle of the first embodiment will be described.

[Engine start control action]
FIG. 4 shows the accelerator position, vehicle G, CL2 torque command, CL1 hydraulic pressure command, ENG rotation speed, MG rotation speed when the engine start request is generated by the system request in the coast regenerative operation in the control device of the first embodiment. It is a time chart which shows each characteristic of PRI rotation speed. Hereinafter, the engine start control operation of the first embodiment will be described with reference to FIG.

In FF hybrid vehicle of Embodiment 1, while regenerated by the motor-generator 4 during the "EV mode", during the coast regenerative operation to the coasting deceleration in a state released accelerator foot, at time t ₁ shown in FIG. 4, for example, indoor air-conditioning When a compressor operation request is output, an engine start request due to a system request is generated.
Thereby, in the flowchart shown in FIG. 3, the process proceeds from step S1 to step S2 to step S3, and a CL2 slip command for setting the second clutch 5 in the slip engagement state is output. At this time, the second clutch torque command (command for the clutch engagement capacity in the second clutch 5) is set to an amount at which a predetermined deceleration due to the regenerative torque of the motor generator 4 during the coast regenerative operation is generated in the vehicle.

At time t ₂ when the clutch engagement capacity of the second clutch 5 (second clutch torque) falls within a predetermined range, the deceleration acting on the vehicle is determined to have become about coast deceleration.
Thus, the process proceeds from step S4 to step S5, and the CL1 hydraulic pressure command for setting the hydraulic pressure of the first clutch 3 to the standby hydraulic pressure and the output rotational speed of the motor generator 4 are reduced to be smaller than the second clutch output rotational speed. MG speed command is output.
For this reason, the engagement hydraulic pressure of the first clutch 3 rises to the standby hydraulic pressure. Further, the rotation speed of the motor generator 4 gradually decreases with time. The motor torque can be increased by reducing the motor speed.

At time t ₃ the time reaches the determination threshold rotational speed of the motor generator 4 is preset, the process proceeds, and the CL1 hydraulic pressure command to the engagement oil pressure of the first clutch 3 cranking hydraulic to step S6 → step S7, horizontal A cranking command for the setting engine 2 is output. As a result, the hydraulic pressure of the first clutch 3 rises to the cranking hydraulic pressure. Since the cranking hydraulic pressure is lower than the engagement hydraulic pressure, the first clutch 3 is in the slip engagement state.
At this time, the motor rotation speed has reached the determination threshold value, which is the rotation speed at which the output torque from the motor generator 4 reaches the torque required for engine cranking. That is, the motor generator 4 is in a state where it can output motor torque necessary for cranking. Therefore, the horizontal engine 2 can be quickly cranked by the motor generator 4.

Then, at time t ₄ when the rotational speed of the transverse engine 2 starts to rise, at a time t ₅ when the motor rotation speed and the engine speed matches. That is, at time t ₅ the time, the rotational difference in first clutch 3 becomes zero. At this time, the motor rotation speed is maintained at the determination threshold value, which is higher than the engine startable rotation speed. That is, in this time t ₅ when the engine speed is above the rotational speed can engine starting. Therefore, the process proceeds to step S9, and a CL1 oil pressure command for changing the oil pressure of the first clutch 3 to the engagement oil pressure is output. Then, the first clutch hydraulic pressure command is increased, since the hydraulic pressure command of the first clutch 3 reaches the engagement hydraulic pressure at time t ₆ time, as the first clutch 3 is engaged, it proceeds to step S10 → step S11 Thus, a CL2 engagement command for engaging the second clutch 5 is output. Thereafter, the second clutch torque command increases, and with the increase of the second clutch torque command, the output rotational speed of the motor generator 4 and the rotational speed of the horizontal engine 2 increase.
At this time, the horizontal engine 2 is not injected and ignited with air and fuel, and the horizontal engine 2 is rotated along with the rotation of the motor generator 4.

Then, at time t ₇ when the engine rotational speed and the motor rotational speed and the transmission input rotation speed (= second clutch output rotational speed) with match, that the second clutch torque command has reached the tightening torque, the Assuming that the engagement of the two-clutch 5 is completed, the engine start control is finished.

As described above, in the hybrid vehicle control apparatus according to the first embodiment, when an engine start request due to a system request is generated in the coast state during the coast regeneration operation, the second clutch 5 is slip-engaged and the second at this time The clutch engagement capacity is set to an amount that generates a predetermined deceleration due to the regenerative torque of the motor generator 4. Further, the motor rotational speed is made smaller than the transmission input rotational speed (= second clutch output rotational speed). Then, the first clutch 3 is slip-engaged, and the motor generator 4 is put in a motoring state in which the horizontally placed engine 2 rotates without fuel injection.

Here, during the coast regenerative operation, since the accelerator is in an OFF state, an unintended push-out shock may occur when the motor torque fluctuation at the time of engine start is transmitted to the wheel axle. On the other hand, since the second clutch 5 is slip-engaged, the motor torque fluctuation of the motor generator 4 due to the engine start is prevented from being transmitted to the left and right

front wheels

10L, 10R which are drive wheels, and the engine start shock Can be suppressed.

Further, it is misunderstood that the vehicle has accelerated without being maintained, but in the first embodiment, the vehicle deceleration during the regenerative operation by the motor generator is maintained, and changes in the vehicle deceleration are absorbed. Can do. For this reason, it can be made not to feel an extrusion shock.

Further, the motor generator 4 has a characteristic that the motor torque decreases as the motor rotation speed increases. That is, the cranking torque may be insufficient at a predetermined motor speed or higher, regardless of the rating of the motor generator.
However, in the first embodiment, the motor torque can be increased by making the rotational speed of the motor generator 4 smaller than the transmission input rotational speed (= second clutch output rotational speed), and quick engine start ( Cranking) can be made possible.

And, when an engine start request is generated due to a system request in a coast state, it is necessary to rotate the horizontal engine 2 (cranking), but the engine combustion torque is not necessarily required. Therefore, by rotating the horizontally placed engine 2 with respect to the motor generator 4 without making fuel (to put the motoring state), unnecessary fuel consumption can be suppressed and fuel consumption can be prevented from deteriorating.

Furthermore, by reducing the rotation speed of the motor generator 4, the first clutch differential rotation at the time of starting the engine, that is, the difference between the engine rotation speed and the motor rotation speed can be reduced. Thereby, the emitted-heat amount of the 1st clutch 3 at the time of engine starting can be reduced, and durability of the 1st clutch 3 can be improved.

Further, in Example 1, when transverse engine 2 is in the motoring state, that is, in after time t ₅ in FIG. 4, and sets the rotation speed of motor generator 4 to the value of the above engine starting rotational speed.
Thereby, when the engine combustion torque is required, the horizontal engine 2 can be quickly exploded, and the required torque can be obtained in a short time.

In the first embodiment, when the rotational speed of the motor generator 4 is reduced, the motor generator 4 is gradually lowered with time. That is, the motor speed is prevented from changing rapidly. As a result, even when the rotational speed of the motor generator 4 is reduced before the second clutch 5 is completely released, it is possible to reduce shocks due to fluctuations in the motor rotational speed and torque.

Further, if the second clutch engagement capacity of the second clutch 5 is increased before the first clutch 3 is completely engaged, the load on the motor generator 4 increases, the motor rotation speed falls, and a vehicle shock occurs. There is a risk.
On the other hand, in the first embodiment, the second clutch 5 maintains the second clutch engagement capacity at such an amount that a predetermined deceleration due to the regenerative torque of the motor generator 4 is generated until the first clutch 3 is completely engaged. And continue the slip fastening. Then, after the first clutch 3 is completely engaged, the engagement of the second clutch 5 is started.
For this reason, it is possible to prevent the motor rotation speed from dropping during engine startup and to prevent the occurrence of a vehicle shock. Further, after the first clutch 3 is engaged, the engine torque can be used in addition to the motor torque. Therefore, when the second clutch 5 is engaged, even if the load on the motor generator 4 increases, it is possible to make it difficult for the rotation speed drop to occur.

Next, the effect will be described.
In the hybrid vehicle control device of the first embodiment, the following effects can be obtained.

(1) The drive system includes an engine (horizontal engine) 2, a motor generator 4, a first clutch 3 interposed between the engine 2 and the motor generator 4, the motor generator 4 and drive wheels (left and right). A second clutch 5 interposed between the

front wheels

10L and 10R, and engine start control means (FIG. 3) for performing engine start control using the motor generator as an engine start motor when an engine start request is generated. In the hybrid vehicle control apparatus provided,
The engine start control means (FIG. 3)
When an engine start request is generated in a coast state during coast regeneration operation by the motor generator 4 in the electric vehicle mode (EV mode) in which the first clutch 3 is disengaged and the second clutch 5 is engaged. ,
A second clutch control section (step S4) for slip-engaging the second clutch 5 and maintaining the second clutch engagement capacity at this time at an amount at which a predetermined deceleration due to the regenerative torque of the motor generator 4 is generated;
A motor rotation speed control unit (step S6) for reducing the rotation speed of the motor generator 4 to be smaller than the second clutch output rotation speed;
A motoring control unit (step S7) that slips the first clutch 3 and puts the engine 2 in a motoring state in which the motor generator 4 rotates without fuel injection;
It was set as the structure which has.
As a result, fuel efficiency can be improved while suppressing changes in vehicle deceleration and engine start shocks at the time of engine start request during coast regenerative operation.

(2) The motor rotation speed control unit is configured to set the rotation speed of the motor generator 4 to a value equal to or higher than the engine startable rotation speed when the engine (horizontal engine) 2 is in a motoring state.
Thereby, in addition to the effect of the above (1), when the engine combustion torque becomes necessary, the horizontal engine 2 can be quickly completed and the required torque can be obtained in a short time.

(3) The motor rotation speed control unit (step S5) is configured to gradually decrease with time when the rotation speed of the motor generator 4 is reduced.
Thereby, in addition to the effect of (1) or (2), even when slip engagement of the second clutch 5 is delayed, shock due to motor rotation speed fluctuation or torque fluctuation can be reduced.

(4) The second clutch control unit maintains the second clutch in a slip-engaged state until the first clutch 3 is completely engaged, and when the first clutch 3 is completely engaged, the second clutch 5 is started (step S10, step S11).
As a result, in addition to the effects (1) to (3) above, it is possible to prevent a drop in the motor speed during engine startup.

The hybrid vehicle control device of the present invention has been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and the invention according to each claim of the claims is described. Design changes and additions are allowed without departing from the gist.

In the first embodiment, when engine cranking is performed, the hydraulic pressure of the first clutch 3 is set to the cranking hydraulic pressure, and the engine is started in the slip engagement state. However, the present invention is not limited to this. The first clutch hydraulic pressure may be set to the engagement hydraulic pressure, and the engine may be started (cranking) after the first clutch 3 is in the engagement state.

Embodiment 1 shows an example in which the hybrid vehicle control device of the present invention is applied to an FF hybrid vehicle. However, the control device of the present invention can be applied not only to FF hybrid vehicles but also to FR hybrid vehicles, 4WD hybrid vehicles, and plug-in hybrid vehicles. In short, it can be applied to any hybrid vehicle.

Further, although an example in which a belt-type continuously variable transmission is used as the automatic transmission has been shown, the present invention is not limited to this, and a stepped automatic transmission may be used. At this time, a clutch or a brake included in the transmission may be used as the second clutch.

Claims

The drive system includes an engine, a motor generator, a first clutch interposed between the engine and the motor generator, and a second clutch interposed between the motor generator and the drive wheel. In a hybrid vehicle control device provided with engine start control means for performing engine start control using the motor generator as an engine start motor when a start request is generated,
The engine start control means includes
During a coast regeneration operation by the motor generator in the electric vehicle mode that travels with the first clutch disengaged and the second clutch engaged, when an engine start request occurs in a coast state,
A second clutch control unit that slip-engages the second clutch, and maintains a second clutch engagement capacity at this time at an amount at which a predetermined deceleration due to the regenerative torque of the motor generator is generated;
A motor rotational speed control unit for reducing the rotational speed of the motor generator and making it smaller than the second clutch output rotational speed;
A motoring control unit that engages or slips the first clutch and puts the engine in a motoring state in which the engine rotates without fuel injection;
A control apparatus for a hybrid vehicle characterized by comprising:
In the hybrid vehicle control device according to claim 1,
The motor rotation speed control unit sets the rotation speed of the motor generator to a value equal to or higher than the engine startable rotation speed when the engine is in a motoring state.
In the hybrid vehicle control device according to claim 1 or 2,
The motor rotation speed control unit gradually decreases with time when the rotation speed of the motor generator is reduced.
In the control apparatus of the hybrid vehicle as described in any one of Claims 1-3,
The second clutch control unit maintains the second clutch in a slip engagement state until the first clutch is completely engaged, and starts the engagement of the second clutch when the first clutch is completely engaged. A control apparatus for a hybrid vehicle characterized by the above.