JP5527159B2 - Control device for hybrid vehicle - Google Patents

Description

  The present invention relates to a control device for a hybrid vehicle.

  As this type of technology, the technology described in Patent Document 1 below is disclosed. In this publication, when there is an engine start request in the electric vehicle running mode, after the motor torque is increased, the second clutch is slid and the first clutch is engaged to start the engine. .

JP 2007-69890 A

In the above prior art, for example, when there is a driver acceleration request, there is a risk that the engine start delay may cause the driver to feel uncomfortable or drive force generation may be delayed.
The present invention has been focused on the above problems, and an object of the present invention is to provide a control device for a hybrid vehicle that can suppress a delay in engine start.

  In order to solve the above-described problem, in the present invention, the engine is started by fastening the engine-side fastening element during the neutral shift in which the opening-side frictional fastening element in the transmission is opened and the speed change is performed during the shift of the transmission. A neutral shift start mode, and a normal start mode in which the engine side fastening element is fastened and the engine is started when the neutral shift is not performed, and the fastening speed of the engine side fastening element in the neutral shift start mode is set to the normal start mode. It was made faster than the fastening speed of the engine side fastening element.

  Therefore, the engine speed increases rapidly, and the engine start can be completed early. For this reason, it is possible to shorten the generation time of torque fluctuation at the time of starting the engine, and to improve the control response of torque.

1 is an overall system diagram illustrating a hybrid vehicle according to a first embodiment. FIG. 3 is a control block diagram of the integrated controller according to the first embodiment. 3 is a target drive torque map of the first embodiment. It is the schematic showing the selection logic of the mode map selection part of Example 1. FIG. 3 is a normal mode map according to the first embodiment. 2 is an MWSC mode map according to the first embodiment. 3 is a target charge / discharge amount map of the first embodiment. FIG. 3 is a schematic diagram illustrating an engine operating point setting process in the WSC traveling mode according to the first embodiment. 4 is a map showing an engine target speed in the WSC travel mode of the first embodiment. 2 is an engine speed map according to the first embodiment. 3 is a flowchart illustrating a flow of a traveling mode switching process according to the first embodiment. 3 is a flowchart showing a flow of engagement processing of a first clutch according to the first embodiment. 2 is a time chart at the time of starting the engine according to the first embodiment.

[Example 1]
[Drive system configuration]
First, the drive system configuration of the hybrid vehicle will be described. FIG. 1 is an overall system diagram showing a hybrid vehicle driven by rear wheels of the first embodiment.

  As shown in FIG. 1, the drive system of the hybrid vehicle in the first embodiment includes an engine E, a first clutch CL1 (engine-side friction element), a motor generator MG, a second clutch CL2, and an automatic transmission AT. And a propeller shaft PS, a differential DF, a left drive shaft DSL, a right drive shaft DSR, a left rear wheel RL (drive wheel), and a right rear wheel RR (drive wheel). FL is the front left wheel and FR is the front right wheel.

  The engine E is, for example, a gasoline engine, and the valve opening degree of the throttle valve and the like are controlled based on a control command from the engine controller 1 described later. The engine output shaft is provided with a flywheel FW.

  The first clutch CL1 is a clutch interposed between the engine E and the motor generator MG, and the control created by the first clutch hydraulic unit 6 based on a control command from the first clutch controller 5 described later. Fastening / release including slip fastening is controlled by hydraulic pressure.

  The motor generator MG is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator, and the three-phase AC generated by the inverter 3 is generated based on a control command from a motor controller 2 described later. It is controlled by applying. The motor generator MG can operate as an electric motor that is driven to rotate by receiving power supplied from the battery 4 (hereinafter, this state is referred to as “powering”), or when the rotor is rotated by an external force. Can function as a generator that generates electromotive force at both ends of the stator coil to charge the battery 4 (hereinafter, this operation state is referred to as “regeneration”). Note that the rotor of the motor generator MG is connected to the input shaft of the automatic transmission AT via a damper (not shown).

  The second clutch CL2 is a clutch interposed between the motor generator MG and the left and right rear wheels RL, RR, and is generated by the second clutch hydraulic unit 8 based on a control command from the AT controller 7 described later. The fastening / release including slip fastening is controlled by the control hydraulic pressure.

  The automatic transmission AT is a transmission that automatically switches the stepped gear ratio such as 5 forward speeds, 1 reverse speed, etc. according to the vehicle speed, accelerator opening, etc., and the second clutch CL2 is newly added as a dedicated clutch However, some frictional engagement elements are used among a plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission AT. The second clutch CL2 does not use the same frictional engagement element, and the frictional engagement element used differs depending on the gear position.

  The output shaft of the automatic transmission AT is connected to the left and right rear wheels RL and RR via a propeller shaft PS, a differential DF, a left drive shaft DSL, and a right drive shaft DSR as vehicle drive shafts. The first clutch CL1 and the second clutch CL2 are, for example, wet multi-plate clutches that can continuously control the oil flow rate and hydraulic pressure with a proportional solenoid.

  This hybrid drive system has three travel modes according to the engaged / released state of the first clutch CL1. The first travel mode is an electric vehicle travel mode (hereinafter abbreviated as “EV travel mode”) as a motor use travel mode that travels using only the power of the motor generator MG as a power source with the first clutch CL1 opened. It is. The second travel mode is an engine use travel mode (hereinafter, abbreviated as “HEV travel mode”) in which the first clutch CL1 is engaged and the engine E is included in the power source. In the third travel mode, the second clutch CL2 is slip-controlled while the first clutch CL1 is engaged, and the engine travel slip travel mode (hereinafter referred to as “WSC travel mode”) is performed while the engine E is included in the power source. ). This mode is a mode in which creep running can be achieved particularly when the battery SOC is low or the engine water temperature is low. When transitioning from the EV travel mode to the HEV travel mode, the first clutch CL1 is engaged and the engine is started using the torque of the motor generator MG.

  Also, when the driver adjusts the accelerator pedal and the accelerator hill hold is performed to maintain the vehicle stop state when the road surface gradient is above a predetermined value, the slip amount of the second clutch CL2 is set in the WSC drive mode. There is a risk that the excessive state will continue. This is because the engine E cannot be made smaller than the idle speed. Therefore, in the first embodiment, the first clutch CL1 is released while the engine E is operated, the second clutch CL2 is slip-controlled while the motor generator MG is operated, and the motor slip that runs using the motor generator MG as a power source is operated. A traveling mode (hereinafter abbreviated as “MWSC traveling mode”) is provided. Details will be described later.

  The “HEV travel mode” has three travel modes of “engine travel mode”, “motor assist travel mode”, and “travel power generation mode”.

  In the “engine running mode”, the drive wheels are moved using only the engine E as a power source. In the “motor-assisted travel mode”, the drive wheels are moved using the engine E and the motor generator MG as power sources. In the “traveling power generation mode”, the motor generator MG is caused to function as a power generator while the drive wheels RR and RL are moved using the engine E as a power source.

  During constant speed operation or acceleration operation, motor generator MG is operated as a generator using the power of engine E. Further, during deceleration operation, braking energy is regenerated and electric power is generated by the motor generator MG and used for charging the battery 4.

  Further, as a further mode, there is a power generation mode in which the motor generator MG is operated as a generator using the power of the engine E when the vehicle is stopped.

[Control system configuration]
Next, the control system configuration of the hybrid vehicle will be described. As shown in FIG. 1, the control system of the hybrid vehicle in the first embodiment includes an engine controller 1, a motor controller 2, an inverter 3, a battery 4, a first clutch controller 5, and a first clutch hydraulic unit 6. The AT controller 7, the second clutch hydraulic unit 8, the brake controller 9, and the integrated controller 10 are configured. The engine controller 1, the motor controller 2, the first clutch controller 5, the AT controller 7, the brake controller 9, and the integrated controller 10 are connected via a CAN communication line 11 that can exchange information with each other. Has been.

  The engine controller 1 inputs the engine speed information from the engine speed sensor 12, and controls the engine operating point (Ne: engine speed, Te: engine torque) according to the target engine torque command from the integrated controller 10, etc. For example, to a throttle valve actuator (not shown). More detailed engine control contents will be described later. Information such as the engine speed Ne is supplied to the integrated controller 10 via the CAN communication line 11.

  The motor controller 2 inputs information from the resolver 13 that detects the rotor rotational position of the motor generator MG, and according to a target motor generator torque command from the integrated controller 10, the motor operating point (Nm: motor generator) of the motor generator MG A command for controlling the rotation speed (Tm: motor generator torque) is output to the inverter 3. The motor controller 2 monitors the battery SOC indicating the state of charge of the battery 4, and the battery SOC information is used for control information of the motor generator MG and is supplied to the integrated controller 10 via the CAN communication line 11. Is done.

  The first clutch controller 5 inputs sensor information from the first clutch hydraulic pressure sensor 14 and the first clutch stroke sensor 15, and engages / disengages the first clutch CL1 according to the first clutch control command from the integrated controller 10. A control command is output to the first clutch hydraulic unit 6. The information on the first clutch stroke C1S is supplied to the integrated controller 10 via the CAN communication line 11.

  The AT controller 7 inputs sensor information from the accelerator opening sensor 16, the vehicle speed sensor 17, the second clutch hydraulic pressure sensor 18, and an inhibitor switch that outputs a signal corresponding to the position of the shift lever operated by the driver. In response to the second clutch control command from 10, a command for controlling engagement / disengagement of the second clutch CL2 is output to the second clutch hydraulic unit 8 in the AT hydraulic control valve. Information on the accelerator pedal opening APO, the vehicle speed VSP, and the inhibitor switch is supplied to the integrated controller 10 via the CAN communication line 11.

  The brake controller 9 inputs the sensor information from the wheel speed sensor 19 for detecting each wheel speed of the four wheels and the brake stroke sensor 20, and regenerates the required braking force obtained from the brake stroke BS when the brake is depressed, for example. When the braking force alone is insufficient, the regenerative cooperative brake control is performed based on the regenerative cooperative control command from the integrated controller 10 so that the shortage is supplemented by the mechanical braking force (braking force by the friction brake).

  The integrated controller 10 manages the energy consumption of the entire vehicle and has a function for running the vehicle with the highest efficiency. The integrated controller 10 detects the motor rotation speed Nm, and the second clutch output rotation speed N2out. A second clutch output speed sensor 22 for detecting the second clutch, a second clutch torque sensor 23 for detecting the second clutch transmission torque capacity TCL2, a brake hydraulic pressure sensor 24, and a temperature sensor 10a for detecting the temperature of the second clutch CL2. Information from the longitudinal acceleration sensor 10b for detecting longitudinal acceleration and information obtained through the CAN communication line 11 are input.

  The integrated controller 10 also controls the operation of the engine E according to the control command to the engine controller 1, the operation control of the motor generator MG according to the control command to the motor controller 2, and the first control command to the first clutch controller 5. Engagement / release control of the clutch CL1 and engagement / release control of the second clutch CL2 by a control command to the AT controller 7 are performed.

[Configuration of integrated controller]
FIG. 2 is a control block diagram of the integrated controller 10. Below, the control calculated by the integrated controller 10 of Example 1 is demonstrated using FIG. For example, this calculation is calculated by the integrated controller 10 every control cycle 10 [msec]. The integrated controller 10 includes a target drive torque calculation unit 100, a mode selection unit 200, a target charge / discharge calculation unit 300, an operating point command unit 400, and a shift control unit 500.

  FIG. 3 is a target drive torque map. The target drive torque calculator 100 calculates the target drive torque Td from the accelerator pedal opening APO and the vehicle speed VSP using the target drive torque map shown in FIG.

  The mode selection unit 200 includes a road surface gradient estimation calculation unit 201 that estimates a road surface gradient based on the detection value of the longitudinal acceleration sensor 10b. The road surface gradient estimation calculation unit 201 calculates the actual acceleration from the wheel speed acceleration average value of the wheel speed sensor 19 and the like, and estimates the road surface gradient from the deviation between the calculation result and the G sensor detection value.

  Furthermore, the mode selection unit 200 includes a mode map selection unit 202 that selects one of two mode maps described later based on the estimated road surface gradient. FIG. 4 is a schematic diagram illustrating the selection logic of the mode map selection unit 202. The mode map selection unit 202 switches to the MWSC compatible mode map when the estimated gradient becomes equal to or greater than the predetermined value g2 from the state in which the normal mode map is selected. On the other hand, when the estimated gradient becomes less than the predetermined value g1 (<g2) from the state where the MWSC compatible mode map is selected, the mode is switched to the normal mode map. That is, a hysteresis is provided for the estimated gradient to prevent control hunting during map switching.

  Next, the mode map will be described. The mode map includes a normal mode map that is selected when the estimated gradient is less than a predetermined value, and an MWSC-compatible mode map that is selected when the estimated gradient is greater than or equal to a predetermined value. FIG. 5 shows a normal mode map, and FIG. 6 shows an MWSC mode map.

  The normal mode map (FIG. 5) has an EV travel mode, a WSC travel mode, and an HEV travel mode, and the target mode is calculated from the accelerator pedal opening APO and the vehicle speed VSP. However, even if the EV travel mode is selected, if the battery SOC is equal to or less than the predetermined value, the “HEV travel mode” is forcibly set as the target mode.

  In the normal mode map of FIG. 5, the HEV → WSC switching line has a rotational speed smaller than the idle rotational speed of the engine E when the automatic transmission AT is in the first speed in the region below the predetermined accelerator opening APO1. It is set in a region lower than the lower limit vehicle speed VSP1. Further, since a large driving torque is required in a region where the accelerator opening APO1 is equal to or larger than the predetermined accelerator opening APO1, the WSC travel mode is set up to a vehicle speed VSP1 ′ region that is higher than the lower limit vehicle speed VSP1. When the battery SOC is low and the EV travel mode cannot be achieved, the WSC travel mode is selected even when starting.

  When the accelerator pedal opening APO is large, it may be difficult to achieve the request with the engine torque corresponding to the engine speed near the idle speed and the torque of the motor generator MG. Here, more engine torque can be output if the engine speed increases. From this, if the engine speed is increased and a larger torque is output, even if the WSC drive mode is executed up to a vehicle speed higher than the lower limit vehicle speed VSP1, the WSC drive mode is changed to the HEV drive mode in a short time. be able to. This case corresponds to the WSC region extended to the lower limit vehicle speed VSP1 ′ shown in FIG.

  The MWSC mode map (FIG. 6) differs from the normal mode map in that the EV drive mode area is not set. Further, the WSC travel mode area is different from the normal mode map in that the area is not changed according to the accelerator pedal opening APO and the area is defined only by the lower limit vehicle speed VSP1. Moreover, it differs from the normal mode map in that the MWSC travel mode area is set in the WSC travel mode area. The MWSC travel mode region is set in a region surrounded by a predetermined vehicle speed VSP2 lower than the lower limit vehicle speed VSP1 and a predetermined accelerator opening APO2 higher than the predetermined accelerator opening APO1. Details of the MWSC travel mode will be described later.

  FIG. 7 is a target charge / discharge amount map. The target charge / discharge calculation unit 300 calculates the target charge / discharge power tP from the battery SOC using the target charge / discharge amount map shown in FIG.

  The operating point command unit 400 uses the accelerator pedal opening APO, the target drive torque Td, the target mode, the vehicle speed VSP, and the target charge / discharge power tP as the target for reaching the operating point, and the transient target engine torque. / Target engine speed, target motor generator torque / target motor generator speed, target second clutch transmission torque capacity, target gear position of automatic transmission AT, and first clutch solenoid current command are calculated. Further, the operating point command unit 400 is provided with an engine start control unit that starts the engine E when the EV travel mode is changed to the HEV travel mode.

  The shift control unit 500 drives and controls the solenoid valve in the automatic transmission AT so as to achieve the target second clutch transmission torque capacity and the target shift speed according to the shift schedule shown in the shift map. In the shift map, a target gear position is set in advance based on the vehicle speed VSP and the accelerator pedal opening APO.

[About WSC drive mode]
Next, details of the WSC travel mode will be described. The WSC travel mode is characterized in that the engine E is maintained in an operating state, and has high responsiveness to a target drive torque change. Specifically, the first clutch CL1 is completely engaged, the second clutch CL2 is slip-controlled as a transmission torque capacity corresponding to the target drive torque, and the vehicle travels using the drive torque of the engine E and / or the motor generator MG.

  In the hybrid vehicle of the first embodiment, there is no element that absorbs the difference in rotational speed unlike the torque converter. Therefore, when the first clutch CL1 and the second clutch CL2 are completely engaged, the vehicle speed is determined according to the rotational speed of the engine E. End up. The engine E has a lower limit value based on the idling engine speed for maintaining the self-sustaining rotation, and the idling engine speed further increases when the engine is idling up by warm-up operation of the engine. In addition, when the target drive torque is high, there may be a case where the HEV traveling mode cannot be quickly changed.

  On the other hand, in the EV travel mode, since the first clutch CL1 is released, there is no limit associated with the lower limit value due to the engine speed. However, in the case where it is difficult to travel in the EV travel mode due to restrictions based on the battery SOC, or in a region where the target drive torque cannot be achieved only by the motor generator MG, there is no means other than generating stable torque by the engine E.

  Therefore, in a vehicle speed range lower than the vehicle speed corresponding to the above lower limit value, and when it is difficult to travel in the EV travel mode, or in a region where the target drive torque cannot be achieved only by the motor generator MG, the engine speed is set to a predetermined value. While maintaining the lower limit rotational speed, the second clutch CL2 is slip-controlled, and the WSC traveling mode for traveling using the engine torque is selected.

  FIG. 8 is a schematic diagram showing the engine operating point setting process in the WSC running mode, and FIG. 9 is a map showing the engine target speed in the WSC running mode.

  When the driver operates the accelerator pedal in the WSC travel mode, the target engine speed characteristic corresponding to the accelerator pedal opening is selected based on FIG. 9, and the target engine speed corresponding to the vehicle speed is set along this characteristic. Is done. Then, the target engine torque corresponding to the target engine speed is calculated by the engine operating point setting process shown in FIG.

  Here, the operating point of the engine E is defined as a point defined by the engine speed and the engine torque. As shown in FIG. 8, it is desirable that the engine operating point is operated on a line (hereinafter referred to as “α line”) connecting operating points with high output efficiency of the engine E.

  However, when the engine speed is set as described above, an operating point away from the α line is selected depending on the accelerator pedal opening APO (target drive torque) by the driver. Therefore, in order to bring the engine operating point closer to the α line, the target engine torque is feedforward controlled to a value that takes the α line into consideration.

  On the other hand, the motor generator MG executes the rotational speed feedback control using the set engine rotational speed as the target rotational speed. Since the engine E and the motor generator MG are now in a direct connection state, the motor generator MG is controlled so as to maintain the target rotational speed, and the rotational speed of the engine E is also automatically feedback-controlled. It becomes.

  At this time, the torque output from the motor generator MG is automatically controlled so as to fill the deviation between the target engine torque and the target drive torque determined in consideration of the α ray. In the motor generator MG, a basic torque control amount (regeneration / power running) is given so as to fill the deviation, and further feedback control is performed so as to match the target engine speed.

  When the target drive torque is smaller than the drive torque on the α line at a certain engine speed, the engine output efficiency increases as the engine output torque is increased. At this time, the motor generator MG recovers the energy corresponding to the increased output, and the torque input to the second clutch CL2 becomes the torque required by the driver, and efficient power generation is possible.

  However, since the upper limit of torque that can be generated is determined according to the state of the battery SOC, the required power generation output (SOC required power generation power) from the battery SOC and the deviation between the torque at the current operating point and the torque on the α line (α It is necessary to consider the magnitude relationship with the (line generated power).

  FIG. 8A is a schematic diagram when the α-ray generated power is larger than the SOC required generated power. Since the engine output torque cannot be increased above the SOC required power generation, the operating point cannot be moved on the α line. However, fuel efficiency is improved by moving to a more efficient point.

  FIG. 8B is a schematic diagram when the α-ray generated power is smaller than the SOC required generated power. Since the engine operating point can be moved on the α line within the SOC required power generation range, in this case, it is possible to generate power while maintaining the operating point with the highest fuel efficiency.

  FIG. 8C is a schematic diagram when the engine operating point is higher than the α line. When the operating point corresponding to the target drive torque is higher than the α line, the engine torque is reduced on the condition that the battery SOC has a margin, and the shortage is compensated by the power running of the motor generator MG. Thereby, a target drive torque can be achieved while improving fuel efficiency.

  Next, the point that the WSC traveling mode area is changed according to the estimated gradient will be described. FIG. 10 is an engine speed map when the vehicle speed is increased in a predetermined state.

  When the accelerator pedal opening is larger than APO1 on a flat road, the WSC drive mode region is executed up to a vehicle speed region higher than the lower limit vehicle speed VSP1. At this time, as the vehicle speed increases, the target engine speed gradually increases as shown in the map of FIG. Then, when the vehicle speed corresponding to VSP1 ′ is reached, the slip state of the second clutch CL2 is canceled and the state transits to the HEV travel mode.

  If an attempt is made to maintain the same vehicle speed increase state as described above on a gradient road where the estimated gradient is larger than the predetermined gradient (g1 or g2), the accelerator pedal opening is increased accordingly. At this time, the transmission torque capacity TCL2 of the second clutch CL2 is larger than that on a flat road. In this state, if the WSC travel mode region is enlarged as shown in the map shown in FIG. 5, the second clutch CL2 will continue to slip with a strong engagement force, and the amount of heat generated may be excessive. is there. Therefore, in the MWSC compatible mode map of FIG. 6 selected when the estimated slope is large, the WSC travel mode area is not unnecessarily widened, but the area corresponding to the vehicle speed VSP1. This avoids excessive heat generation in the WSC travel mode.

[About MWSC drive mode]
Next, the reason why the MWSC travel mode area is set will be described. When the estimated gradient is larger than the predetermined gradient (g1 or g2), for example, if the vehicle is to be kept in a stopped state or a slow start state without operating the brake pedal, a large driving torque is required compared to a flat road . This is because it is necessary to face the load load of the host vehicle.

  From the viewpoint of avoiding heat generation due to the slip of the second clutch CL2, it is also conceivable to select the EV travel mode when the battery SOC has a margin. At this time, it is necessary to start the engine when transitioning from the EV travel mode region to the WSC travel mode region, and the motor generator MG outputs the drive torque while securing the engine start torque, so the drive torque upper limit value is unnecessary. It is narrowed to.

  Moreover, when only the torque is output to the motor generator MG in the EV travel mode and the motor generator MG stops or rotates at a very low speed, a lock current flows through the switching element of the inverter (a phenomenon in which the current continues to flow through one element), There is a risk of lowering durability.

  Further, in a region lower than the lower limit vehicle speed VSP1 corresponding to the idle speed of the engine E at the first speed (region of VSP2 or less), the engine E itself cannot be reduced below the idle speed. At this time, if the WSC travel mode is selected, the slip amount of the second clutch CL2 increases, which may affect the durability of the second clutch CL2.

  In particular, since a large driving torque is required on a slope road compared to a flat road, the transmission torque capacity required for the second clutch CL2 is increased, and a high torque and high slip amount state is continued. Tends to cause a decrease in durability of the second clutch CL2. In addition, since the vehicle speed rises slowly, it takes time until the transition to the HEV travel mode, and there is a risk of further generating heat.

  Therefore, the first clutch CL1 is released while the engine E is operated, and the transmission torque capacity of the second clutch CL2 is controlled to the driver's target drive torque, while the rotational speed of the motor generator MG is the second clutch CL2. An MWSC driving mode was set in which feedback control is performed to a target rotational speed that is higher than the output rotational speed by a predetermined rotational speed.

  In other words, the second clutch CL2 is slip-controlled while the rotational state of the motor generator MG is set to a rotational speed lower than the idle rotational speed of the engine. At the same time, the engine E switches to feedback control in which the idling speed is the target speed. In the WSC travel mode, the engine speed was maintained by the rotational speed feedback control of the motor generator MG. On the other hand, when the first clutch CL1 is released, the engine speed cannot be controlled to the idle speed by the motor generator MG. Therefore, engine speed feedback control is performed by the engine E itself.

The effects listed below can be obtained by setting the MWSC travel mode area.
1) Since the engine E is in an operating state, it is not necessary to leave the driving torque for starting the engine in the motor generator MG, and the driving torque upper limit value of the motor generator MG can be increased. Specifically, when viewed on the target drive torque axis, it is possible to cope with a target drive torque higher than that in the EV travel mode region.

2) The durability of the switching element and the like can be improved by ensuring the rotation state of the motor generator MG.
3) Since the motor generator MG is rotated at a rotational speed lower than the idle rotational speed, the slip amount of the second clutch CL2 can be reduced, and the durability of the second clutch CL2 can be improved.

[Driving mode switching process]
FIG. 11 is a flowchart showing a flow of a traveling mode switching process performed by the mode selection unit 200.
In step S1, it is determined whether or not the normal mode map is selected. If the normal mode map is selected, the process proceeds to step S2, and if the MWSC compatible mode map is selected, the process proceeds to step S11.

  In step S2, it is determined whether or not the estimated gradient is larger than a predetermined value g2. If it is larger, the process proceeds to step S3, and otherwise, the process proceeds to step S15 to execute control processing based on the normal mode map.

In step S3, the normal mode map is switched to the MWSC compatible mode map.
In step S4, it is determined whether or not the operating point determined by the current accelerator pedal opening and vehicle speed is within the MWSC travel mode region. If it is determined that the operating point is within the region, the process proceeds to step S5, If it is determined that there is not, the process proceeds to step S8.

  In step S5, it is determined whether or not the battery SOC is larger than the predetermined value A. When the battery SOC is larger than the predetermined value A, the process proceeds to step S6. When the battery SOC is smaller than the predetermined value A, the process proceeds to step S9. Here, the predetermined value A is a threshold value for determining whether or not the drive torque can be secured only by the motor generator MG. When SOC is larger than the predetermined value A, the drive torque can be secured only by the motor generator MG. When the SOC is lower than the predetermined value A, the battery 4 needs to be charged, so the selection of the MWSC traveling mode is prohibited. .

  In step S6, it is determined whether or not the transmission torque capacity TCL2 of the second clutch CL2 is less than a predetermined value B. If it is less than the predetermined value B, the process proceeds to step S7, and if it is greater than the predetermined value B, the process proceeds to step S9. Here, the predetermined value B is a predetermined value indicating that an excessive current does not flow through the motor generator MG. Since motor generator MG is controlled in rotational speed, the torque generated in motor generator MG is greater than or equal to the load acting on motor generator MG.

  In other words, since the motor generator MG is controlled in rotational speed so that the second clutch CL2 is in the slip state, a torque larger than the second clutch transmission torque capacity TCL2 is generated in the motor generator MG. Therefore, when the transmission torque capacity TCL2 of the second clutch CL2 is excessive, the current flowing through the motor generator MG becomes excessive, and the durability of the switching element and the like deteriorates. In order to avoid this state, selection of the MWSC travel mode is prohibited when the value is equal to or greater than the predetermined value B.

  In step S7, MWSC control processing is executed. Specifically, the first clutch CL1 is released while the engine is operating, the engine E is set to feedback control so as to be at the idle speed, and the motor generator MG is set to the output speed Ncl2out of the second clutch CL2 at a predetermined speed. The feedback control is performed with a target rotational speed obtained by adding α (however, a value lower than the idle rotational speed), and the second clutch CL2 is configured with a transmission torque capacity corresponding to the target driving torque. Since the MWSC travel mode is not set in the normal mode map, the MWSC control process in step S7 includes a mode transition process from the EV travel mode or the WSC travel mode.

  In step S8, it is determined whether or not the operating point determined by the current accelerator pedal opening and the vehicle speed is within the WSC travel mode region. When it is determined that the operating point is within the region, the process proceeds to step S9. When it is determined that the vehicle is in the HEV travel mode area, the process proceeds to step S10.

  In step S9, WSC control processing is executed. Specifically, the first clutch CL1 is completely engaged, the engine E is set to feedforward control according to the target torque, the motor generator MG is set to feedback control at an idle speed, and the second clutch CL2 is set according to the target drive torque. The feedback control with the transmission torque capacity. Since the EV travel mode is not set in the MWSC compatible mode map, the WSC control process in step S9 includes a mode transition process from the EV travel mode.

  In step S10, HEV control processing is executed. Specifically, the first clutch CL1 is completely engaged, the feedforward control is performed so that the engine E and the motor generator MG have a torque corresponding to the target drive torque, and the second clutch CL2 is completely engaged. Since the EV travel mode is not set in the MWSC compatible mode map, the HEV control process in step S10 includes a mode transition process from the EV travel mode.

  In step S11, it is determined whether or not the estimated gradient is less than a predetermined value g2. If it is less than g2, the process proceeds to step S12. Otherwise, the process proceeds to step S4 and the control by the MWSC correspondence mode map is continued.

In step S12, the mode map is switched from the MWSC compatible mode map to the normal mode map.
In step S13, it is determined whether or not the travel mode has been changed in accordance with the map switching. If it is determined that the travel mode has been changed, the process proceeds to step S14. Otherwise, the process proceeds to step S15. This is because switching from the MWSC compatible mode map to the normal mode map may cause a transition from the MWSC travel mode to the WSC travel mode, a transition from the WSC travel mode to the EV travel mode, and a transition from the HEV travel mode to the EV travel mode. .

  In step S14, a travel mode change process is executed. Specifically, at the time of transition from the MWSC travel mode to the WSC travel mode, the target rotational speed of the motor generator MG is changed to the idle rotational speed, and the first clutch CL1 is engaged at the synchronized stage. Then, the engine control is switched from the idle speed feedback control to the target engine torque feedforward control.

  At the time of transition from the WSC drive mode to the EV drive mode, the first clutch CL1 is released, the engine E is stopped, the motor generator MG is switched from the rotation speed control to the torque control based on the target drive torque, and the second clutch CL2 Is switched from feedback control based on the target drive torque to complete engagement.

At the time of transition from the HEV drive mode to the EV drive mode, the first clutch CL1 is released, the engine E is stopped, the motor generator MG continues the torque control based on the target drive torque, and the second clutch CL2 is the target drive. Switch from torque-based feedback control to complete engagement.
In step S15, control processing based on the normal mode map is executed.

[First clutch engagement process]
FIG. 12 is a flowchart showing a flow of engagement processing of the first clutch CL1 performed in the operating point command unit 400.

  In step S21, it is determined whether or not there is an engine start request. If there is an engine start request, the process proceeds to step S22, and if there is no engine start request, the process ends. The engine start request is issued, for example, when the driving range is changed from the EV drive mode to the WSC drive mode due to the driver's acceleration request, and when the power generation request is issued because the battery SOC is reduced, the compressor drive request for the air conditioner is issued. Is output when

  In step S22, it is determined whether or not the second clutch CL2 is in the slip state. If the second clutch CL2 is in the slip state, the process proceeds to step S23, and if not, the determination in step S22 is repeated.

  In step S23, it is determined whether or not a neutral shift is performed. When the neutral shift is performed, the process proceeds to step S24. When the neutral shift is not performed, the process proceeds to step S25. Neutral speed change refers to a speed change in which the opening side frictional engagement element in the automatic transmission AT is released and then the engagement side frictional engagement element is engaged. During normal gear shifting, the engagement of the engagement side frictional engagement element is started with the open side frictional engagement element slipped. At the time of the neutral shift, the engine E and the motor generator MG are used until the engagement side frictional engagement element in the automatic transmission AT is engaged after the release side frictional engagement element in the automatic transmission AT is released. Is not transmitted to the drive wheels RL and RR. When the engine is started during the neutral shift, the neutral shift start mode is set. When the engine is started when the neutral shift is not performed, the normal shift start mode is set.

  In step S24, the first clutch CL1 is fastened and fastened, and the process ends. The state where the engagement speed is high indicates a state where the engagement speed is faster than the engagement speed when neutral shift is not performed, and the transmission that is immediately completed when the engine start request is output as the command first clutch transmission torque capacity. The torque capacity is set and the system is set as fast as possible.

  In step S25, it is determined whether or not the engine is started by depressing the accelerator pedal. When the engine is started by depressing the accelerator pedal, the process proceeds to step S26, and when the engine is not started by depressing the accelerator pedal, the process proceeds to step S27. Engine start by depressing the accelerator pedal refers to engine start that is performed when the driving region shifts from the EV travel mode to the WSC travel mode in response to a driver's acceleration request.

  In step S26, the engagement speed of the first clutch CL1 is set according to the gear position of the automatic transmission AT, the first clutch is engaged at the set engagement speed, and the process ends. The setting of the engagement speed is performed based on the transmission torque characteristics of the friction engagement elements that are engaged at each speed.

  In step S27, the engagement speed of the first clutch CL1 is lowered, the input of steep torque fluctuations on the drive wheels RL, RR side can be suppressed, the engagement is gradually performed, and the process is terminated.

[First clutch engagement processing operation]
When there is an engine start request and the second clutch CL2 is in the slip state, the process proceeds from step S21 to step S22 to step S23 in the flowchart of FIG.

  Here, when the neutral shift is being performed, the process proceeds to step S24, and the first clutch CL1 is fastened at high speed. During neutral gear shifting, torque fluctuations at engine start are not transmitted to the drive wheels RL and RR. Furthermore, since the engagement of the first clutch CL1 can be finished early, the delay from the engine start request to the start can be reduced.

  When the neutral shift is not being performed and the engine is started by depressing the accelerator pedal, the process proceeds from step S25 to step S26, and the first clutch CL1 is set at the engagement speed set in accordance with the shift stage of the automatic transmission AT. 1 clutch is engaged. When the torque transmission performance of the frictional engagement element that is engaged in the automatic transmission AT is high, the engagement speed can be reduced to suppress the input of torque fluctuations to the drive wheels RL and RR. When the torque transmission performance of the frictional engagement element that is engaged in the AT is low, the engine speed can be increased by increasing the engagement speed.

  When the engine is started due to a request from the system (such as when a power generation request is issued because the battery SOC is low, or when an air conditioner compressor drive request is issued) when the neutral shift is not performed Then, the process proceeds from step S25 to step S27, and the first clutch CL1 is engaged at a low engagement speed. By gradually tightening, steep torque fluctuations are not input to the drive wheels RL and RR.

〔Time chart〕
FIG. 13 is a time chart when the engine is started, FIG. 13A shows a time chart when neutral shift, FIG. 13B shows a request from the system side, and FIG. 13C shows a time chart when the accelerator is depressed.

  The shift stage before the shift is the first shift stage, and the shift stage after the shift is the second shift stage. In the third time chart from the top of FIG. 13A, the broken line indicates the command value of the transfer torque capacity of the frictional engagement element on the open side in the automatic transmission AT, and the solid line indicates the value in the automatic transmission AT. The command value of the transmission torque capacity of the engagement side frictional engagement element is shown. As shown in FIG. 13 (a), when the engine is started during the neutral shift, when the engine start request is output after the release-side frictional engagement element (shift clutch) is released, the motor generator speed is increased, The command second clutch transmission torque capacity is reduced, and the second clutch CL2 is brought into the slip state. The command first clutch transmission torque capacity is raised so that the first clutch CL1 is immediately fully engaged, and is engaged at a high engagement speed of the first clutch CL1. Until the engagement of the first clutch CL1 is finished, it waits for the engagement of the frictional engagement element (transmission clutch) to be engaged at the second gear, and as soon as the engine start is completed, the gear clutch to be engaged at the second gear is engaged Therefore, the delay of the shift is suppressed.

  As shown in FIG. 13 (b), in the engine start at the time of the system request, when the engine start request is output, the motor generator rotational speed is increased at the time of driving, the command second clutch transmission torque capacity is decreased, 2. Set the clutch CL2 to the slip state. On the other hand, during coasting, the command second clutch transmission torque capacity is reduced without increasing the motor generator rotational speed, and the second clutch CL2 is brought into the slip state. When the second clutch CL2 enters the slip state, the command first clutch transmission torque capacity is gradually increased, and the first clutch CL1 is slowly engaged. When the engine start is completed, the command first clutch transmission torque capacity is increased so that the first clutch CL1 is completely engaged.

  As shown in FIG. 13 (c), when the engine is started when the accelerator is depressed, when the engine start request is output, the motor generator rotational speed is increased, the command second clutch transmission torque capacity is decreased, and the second clutch Set CL2 to the slip state. When the second clutch CL2 enters the slip state, the command first clutch transmission torque capacity is increased at the engagement speed set according to the gear position of the automatic transmission AT, and the first clutch CL1 starts to be engaged. When the engine start is completed, the command first clutch transmission torque capacity is raised so that the first clutch CL1 is completely engaged.

[Action]
If the first clutch is fastened, torque fluctuations at the start of the engine will be transmitted to the drive wheels RL and RR. However, if the driver is requested to accelerate, if the first clutch is late, the engine will be delayed and accelerated. Responsiveness will deteriorate.

  Therefore, in the first embodiment, the engagement speed of the first clutch CL1 at the start of the engine at the neutral shift is made faster than the engagement speed of the first clutch CL1 at the start of the engine at the time of not the neutral shift. In particular, in the first embodiment, when starting the engine during the neutral shift, the first clutch CL1 is engaged between the release of the frictional engagement element on the release side of the shift and the engagement of the frictional engagement element on the engagement side of the shift. The first clutch CL1 is immediately fully engaged by setting the engagement speed higher than the engagement speed at the time of normal engine start. As a result, the engine speed increases rapidly, and the engine start can be completed early. For this reason, it is possible to shorten the generation time of torque fluctuation at the time of starting the engine, and to improve the control response of torque.

  Further, in the first embodiment, when the engine start when the neutral shift is not being performed is the engine start according to the system request, the engagement speed of the first clutch CL1 is set to the engagement speed of the first clutch CL1 when the engine is started by depressing the accelerator pedal. I made it slower than the speed. Thereby, steep torque fluctuation at the time of engine start can be reduced, and transmission of torque fluctuation to the drive wheels RL and RR can be suppressed.

  Further, in the first embodiment, when the engine start when the neutral shift is not being performed is the engine start by depressing the accelerator pedal, the engagement speed of the first clutch CL1 is made variable according to the gear position of the automatic transmission AT. As a result, when the torque transmission performance of the frictional engagement element that is engaged in the automatic transmission AT is high, it is possible to suppress the input of torque fluctuations to the drive wheels RL and RR by lowering the engagement speed. Further, when the torque transmission performance of the frictional engagement element engaged in the automatic transmission AT is low, the engine can be started quickly by increasing the engagement speed.

〔effect〕
Next, the effect obtained by Example 1 is described below.

  (1) Engine E, motor generator MG that outputs the driving torque of the vehicle and starts engine E, and automatic transmission AT that shifts and outputs the output rotational speed from engine E and / or motor generator MG ( Transmission), a first clutch CL1 (engine-side engagement element) that is interposed between the engine E and the motor generator MG and connects and disconnects the engine E and the motor generator MG, and an automatic transmission when the automatic transmission AT shifts The neutral clutch start mode in which the first clutch CL1 is engaged and the engine is started during the neutral shift in which the frictional engagement element on the open side in the AT is released to perform the shift, and the first clutch CL1 is engaged when the neutral shift is not performed. A normal start mode in which the engine E is started, and the engagement speed of the first clutch CL1 in the neutral shift start mode is determined in the normal start mode. And Kino first operating point command section 400 for faster than engagement speed of the clutch (first clutch control means), and the provided.

  Therefore, the engine speed increases rapidly, and the engine start can be completed early. For this reason, it is possible to shorten the generation time of torque fluctuation at the time of starting the engine, and to improve the control response of torque.

  (2) In the normal start mode, the operating point command unit 400 determines the engagement speed of the first clutch CL1 when the engine is started by a system request (when there is no vehicle acceleration request). The engagement speed of the first clutch CL1 was made slower.

  Therefore, steep torque fluctuations at the time of engine start can be reduced, and transmission of torque fluctuations to the drive wheels RL and RR can be suppressed.

  (3) The operating point command unit 400 is in the normal start mode and when the engine is started by depressing the accelerator pedal (when there is a request for acceleration of the vehicle), the operating point command unit 400 sets the first clutch CL1 according to the gear position of the automatic transmission AT. The fastening speed was made variable.

  Therefore, when the torque transmission performance of the fastened frictional engagement element in the automatic transmission AT is high, it is possible to suppress the input of torque fluctuation to the drive wheels RL and RR by reducing the engagement speed. Further, when the torque transmission performance of the frictional engagement element engaged in the automatic transmission AT is low, the engine can be started quickly by increasing the engagement speed.

[Other embodiments]
The best mode for carrying out the present invention has been described based on the first embodiment. However, the specific configuration of the present invention is not limited to the first embodiment and does not depart from the gist of the present invention. Any change in the design of the range is included in the present invention.

  In the first embodiment, the FR hybrid vehicle has been described. However, an FF hybrid vehicle may be used.

E engine
MG motor generator
AT automatic transmission (transmission)
RL Left drive wheel (drive wheel)
RR Right drive wheel (drive wheel)
CL1 1st clutch (Engine side fastening element)
400 Operating point command section (Engine side fastening element control means)

Claims (3)

Engine,
A motor generator for outputting the driving torque of the vehicle and starting the engine;
A transmission for shifting and outputting an output rotational speed from the engine and / or the motor generator;
An engine-side fastening element that is interposed between the engine and the motor generator and connects and disconnects the engine and the motor generator;
A neutral shift start mode in which the engine-side engagement element is engaged and the engine is started during a neutral shift in which an open-side frictional engagement element in the transmission is released to perform a shift at the time of the shift of the transmission; and the neutral shift A normal start mode in which the engine side fastening element is fastened and the engine is started, and the fastening speed of the engine side fastening element in the neutral shift start mode is the same as that in the normal start mode. Engine side fastening element control means for making the fastening speed of the engine side fastening element faster than the fastening speed;
A control apparatus for a hybrid vehicle, comprising: In the hybrid vehicle control device according to claim 1,
In the normal start mode, the engine side fastening element control means determines the fastening speed of the engine side fastening element when there is no vehicle acceleration request, and the engine side fastening element when there is a vehicle acceleration request. A control apparatus for a hybrid vehicle, characterized by being slower than a fastening speed. In the hybrid vehicle control device according to claim 1 or 2,
The engine side fastening element control means makes the fastening speed of the engine side fastening element variable in accordance with the gear position of the transmission when the vehicle is requested to accelerate in the normal start mode. A control device for a hybrid vehicle.

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