JP5598256B2 - 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, in the MWSC travel mode, the first clutch is released while the engine is driven, and in the WSC travel mode, the first clutch is engaged and the second clutch is slip-controlled while the engine is driven. It is disclosed.

JP 2009-132195 A

In the above prior art, the engine idle speed is not changed when the first clutch is released and when the first clutch is engaged. However, when the first clutch is engaged, the vibration of the engine is transmitted to the drive system below the first clutch. Therefore, if the engine idle speed matches the resonance speed of the other drive system, a large vibration or noise is generated. There was a risk.
The present invention has been focused on the above-described problems, and an object of the present invention is to provide a control device for a hybrid vehicle that can suppress vibration and sound during engine idling.

In order to solve the above-described problem, in the present invention, the first fastening element is released while the engine is operated at a predetermined rotational speed, and the second fastening element is slip-fastened with the motor generator set to a rotational speed lower than the predetermined rotational speed. when the motor slip drive control sets a target engine speed during idling of the engine to the first target idle speed to increase the fuel efficiency of the engine, and engaging the first engagement element, the engine is equal to or higher than a predetermined rotational speed and to second target idle speed suppressing resonance due to the engine target engine speed during idling of the engine when the engine-used slip drive control for slip-engagement of the second engagement element before and controls the motor generator such that Was set to.

  Therefore, it is possible to suppress the generation of vibration and sound during engine idling.

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. FIG. 3 is a control block diagram of an idle speed setting unit according to the first embodiment. 3 is a flowchart illustrating a flow of control for obtaining an engine idle speed according to the first embodiment. It is a figure which shows the setting of the 2nd target idle speed of Example 1. FIG.

[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, a motor generator MG, a second clutch CL2, an automatic transmission AT, a propeller shaft PS, It has 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. Details will be described later.

  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 required 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 required 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 required drive torque is high, it may not be possible to quickly transition to the HEV travel mode.

  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 required 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 required 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 be 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 (required 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 determined in consideration of the α-ray and the required drive torque. 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 required 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 required 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. As a result, the required drive torque can be achieved while improving the 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 required driving torque, while the rotation 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 required drive torque axis, it is possible to cope with a higher required drive torque than 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 the flow of the travel mode switching process.
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 a target rotational speed (a value lower than the idle rotational speed) obtained by adding α, and the second clutch CL2 is a feedback control having a transmission torque capacity corresponding to the required 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 that becomes the idling speed, and the second clutch CL2 is set according to the required 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 required 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 requested drive torque, and the second clutch CL2 Is switched from feedback control based on the required 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 required drive torque, and the second clutch CL2 is requested. Switch from torque-based feedback control to complete engagement.
In step S15, control processing based on the normal mode map is executed.

[Setting engine idle speed]
FIG. 12 is a control block diagram of the idle speed setting unit 401 that sets a target engine speed at the time of engine idle control performed by the operating point command unit 400. The idle rotation speed setting unit 401 includes a first clutch release idle rotation speed setting unit 402, a first clutch engagement idle rotation speed calculation unit 403, a switching unit 404, and an upper / lower limit processing unit 405. .

  The first clutch release idle speed setting unit 402 receives the first clutch protection request, and calculates the engine idle speed when the first clutch CL1 is released. Specifically, the engine idle speed in the MWSC travel mode is calculated.

  In the MWSC travel mode, the engine idle speed (first target idle speed) is normally set so as to improve the fuel efficiency of the engine E. However, when the protection request for the first clutch CL1 is issued, the second target idle speed described later is set. As will be described later, in the WSC traveling mode, the second target idle speed is normally set. When shifting from the MWSC travel mode to the WSC travel mode, the change in the rotational speed of the engine E is suppressed to suppress the slip of the first clutch CL1 that occurs at the time of engagement.

  The idle speed setting unit 403 when the first clutch is engaged receives the battery SOC and the engine idle speed increase request, and calculates the engine idle speed when the first clutch CL1 is engaged. Specifically, the engine idle speed in the WSC traveling mode is calculated. In the WSC travel mode, the engine is driven with the first clutch engaged. At this time, the rotational speed of the engine E is also controlled by controlling the rotational speed of the motor generator MG.

  In the WSC travel mode, the engine idle speed (second target idle speed) is normally set so as to avoid that the vibration of engine E matches the resonant vibration of motor generator MG. However, when there is a demand for power generation by the motor generator MG due to a decrease in the battery SOC, or when it is necessary to increase the output torque by increasing the engine idle speed to drive the compressor of the air conditioner, the demand for power generation or the engine The engine idle speed is set according to the request for increasing the idle speed.

  The switching unit 44 inputs a travel mode corresponding to the current operation region, outputs the engine idle speed from the first clutch disengagement idle speed setting unit 402 in the MWSC travel mode, and in the WSC travel mode. Outputs the engine idle speed from the idle speed setting unit 402 when the first clutch is engaged.

  The upper / lower limit processing unit 405 inputs the travel range and the engine water temperature, and calculates the upper limit value and the lower limit value of the engine idle speed according to the travel range and the engine water temperature. When the output of the switching unit 404 exceeds the upper limit value, the upper limit value is output. When the output of the switching unit 404 is lower than the lower limit value, the lower limit value is output. To do.

FIG. 13 is a flowchart showing a flow of control for obtaining the engine idle speed.
In step S1, it is determined whether or not a release request for the first clutch CL1 has been issued.
The state in which the release request is issued to the first clutch CL1 specifically indicates that the operation region is the MWSC travel mode. When the release request is issued to the first clutch CL1, the process proceeds to step S2, and when the release request is not issued to the first clutch CL1, the process proceeds to step S4.

  In step S2, it is determined whether a protection request for the first clutch CL1 has been issued. The case where the protection request for the first clutch CL1 is issued means that the friction plate of the first clutch CL1 is worn or heat is generated. When the protection request for the first clutch CL1 is issued, the process proceeds to step S5, and when the protection request for the first clutch CL1 is not issued, the process proceeds to step S3.

  In step S3, the engine idle speed is set to the first target idle speed. The first target idle speed is the engine idle speed when the fuel efficiency of the engine E becomes good.

  In step S4, it is determined whether or not there is an engine idle speed increase request. If there is an engine idle speed increase request, the process proceeds to step S6. If there is no engine idle speed increase request, the process proceeds to step S5. When there is a request to increase the engine idle speed, when the battery SOC is reduced and there is a power generation request by the motor generator MG, or to drive the compressor of the air conditioner, the engine idle speed is increased to increase the output torque. Show when you need to.

In step S5, the engine idle speed is set to the second target idle speed. FIG. 14 is a diagram showing the setting of the second target idle speed. As shown in FIG. 14, the second target idle rotational speed is higher than the rotational speed region where the vibration of engine E matches the resonant vibration of motor generator MG, and lower than the rotational speed region where excessive heat generation of second clutch CL2 occurs. Set to a number.
In step S6, an idle speed is set according to the engine idle speed increase request.

[Action]
Normally, the engine idle speed is set in consideration of ensuring self-sustained rotation of the engine E and fuel consumption. When the first clutch CL1 is released, the vibration associated with the rotation of the engine E is not transmitted to the drive system below the first clutch CL1, so that the engine idle rotation can be performed without considering resonance with other drive systems. Number can be set. However, when the first clutch CL1 is engaged, the vibration associated with the rotation of the engine E is also transmitted to the drive system below the first clutch CL1, so the engine set in consideration of ensuring self-sustained rotation of the engine E and fuel consumption If the idle speed matches the resonant speed of the other drive system, there is a risk of generating large vibrations and sounds.

  Therefore, in the first embodiment, when the first clutch CL1 is released, the target engine speed when the engine E is idle is set to the first target idle speed that increases the fuel efficiency of the engine E, and the first clutch CL1 is engaged. When the engine E is idling, the target engine speed during idling of the engine E is set to the second target idle speed that suppresses resonance by the engine E.

  As a result, fuel consumption can be improved when the first clutch CL1, which does not need to consider the resonance between the engine E and another drive system, is released, and the resonance between the engine E and another drive system is taken into account. When the first clutch CL1 that is required to be engaged is engaged, the generation of sound and vibration can be suppressed.

  In the first embodiment, the second target idle rotation speed is set to a rotation speed that is excluded from the resonance rotation speed of engine E and motor generator MG.

  As a result, the second target idle rotation speed can be set by removing the resonance rotation speed with the motor generator MG to which the vibration accompanying the rotation of the engine E is directly input, so that the generation of sound and vibration can be suppressed.

  In the first embodiment, the target engine speed when the engine E is idle is set to the first target idle speed when in the MWSC travel mode, and the target engine speed when the engine E is idle is set to the second speed when in the WSC travel mode. The target idle speed was set.

  This makes it possible to improve fuel efficiency in MWSC driving modes that do not require consideration of resonance between engine E and other drive systems, and WSC driving that requires consideration of resonance between engine E and other drive systems. Generation of sound and vibration can be suppressed in the mode.

  In the first embodiment, when there is a protection request for the first clutch CL1 in the MWSC travel mode, the target engine speed when the engine E is idle is set to the second target idle speed.

  As a result, when shifting from the MWSC drive mode to the WSC drive mode, it is possible to suppress the change in the rotational speed of the engine E and to suppress the slip of the first clutch CL1 that occurs at the time of engagement, and to protect the first clutch CL1. can do.

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

  (1) An engine E, a motor generator MG that outputs the driving torque of the vehicle and starts the engine E, and a first engine that is interposed between the engine E and the motor generator MG and connects and disconnects the engine E and the motor generator MG. 1 clutch CL1 (first engagement element) and a second clutch CL2 (connected between the motor generator MG and the drive wheel, which is interposed between the motor generator MG and the drive wheel (left drive wheel RL, right drive wheel RR)) When the first clutch CL1 is released, the target engine speed when the engine E is idling is set to the first target idle speed that increases the fuel efficiency of the engine E, and the first clutch CL1 When the engine is engaged, an idle speed setting unit 401 is provided for setting the target engine speed when the engine E is idle to a second target idle speed that suppresses resonance by the engine E. It was.

  Therefore, fuel efficiency can be improved when the first clutch CL1, which does not need to consider the resonance between the engine E and another drive system, is released, and the resonance between the engine E and another drive system must be taken into account. When the first clutch CL1 that requires the above is engaged, it is possible to suppress the generation of noise and vibration.

  (2) The idle speed setting unit 401 sets the second target idle speed to a speed that is excluded from the resonant speed of the engine E and the motor generator MG.

  Therefore, since the second target idle speed can be set by removing the resonance speed with the motor generator MG to which the vibration accompanying the rotation of the engine E is directly input, the generation of sound and vibration can be suppressed.

  (3) The idle speed setting unit 401 releases the first clutch CL1 while operating the engine E at a predetermined speed, and slip-engages the second clutch CL2 by setting the motor generator MG to a speed lower than the predetermined speed. In the MWSC travel mode (motor slip travel control), the target engine speed when the engine E is idle is set to the first target idle speed, the first clutch CL1 is engaged, and the engine E becomes equal to or higher than the predetermined speed. When the engine generator is controlled and the second clutch CL2 is slip-engaged in the WSC travel mode (engine-use slip travel control), the target engine speed when the engine E is idle is set to the second target idle speed. did.

  Therefore, fuel consumption can be improved in the MWSC drive mode that does not require consideration of resonance between the engine E and another drive system, and WSC drive mode that requires consideration of resonance between the engine E and another drive system. In this case, generation of sound and vibration can be suppressed.

  (4) The idle speed setting unit 401 sets the target engine speed during idling of the engine E to the second target idle speed when there is a protection request for the first clutch CL1 in the MWSC travel mode. I made it.

  When shifting from the MWSC drive mode to the WSC drive mode, it is possible to suppress the change in the rotational speed of the engine E and to suppress the slip of the first clutch CL1 that occurs at the time of engagement, and to protect the first clutch CL1. it can.

[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.

  For example, although the FR type hybrid vehicle has been described in the first embodiment, it may be an FF type hybrid vehicle.

E engine
MG motor generator
RL Left drive wheel (drive wheel)
RR Right drive wheel (drive wheel)
CL1 1st clutch (1st engagement element)
CL2 2nd clutch (2nd engagement element)
401 Idle speed setting section (Idle speed setting means)

Claims (3)

An engine,
A motor generator for outputting the driving torque of the vehicle and starting the engine;
A first fastening element interposed between the engine and the motor generator to connect and disconnect the engine and the motor generator;
A second fastening element interposed between the motor generator and the drive wheel to connect and disconnect the motor generator and the drive wheel;
When the first fastening element is released, the target engine speed when the engine is idle is set to a first target idle speed that increases the fuel consumption of the engine, and when the first fastening element is fastened Idle speed setting means for setting the target engine speed when the engine is idling to a second target idle speed that suppresses resonance by the engine;
Provided ,
The idle speed setting means includes
The first fastening element is released with the engine operating at a predetermined rotational speed, and the motor generator is in a motor slip traveling control in which the motor generator is set to a rotational speed lower than the predetermined rotational speed and the second fastening element is slip-engaged. Setting the target engine speed when the engine is idling to the first target idle speed,
When the engine is in the slip running control in which the first fastening element is fastened and the motor generator is controlled to slip-fasten the second fastening element so that the engine is equal to or higher than the predetermined rotational speed, A control apparatus for a hybrid vehicle, wherein a target engine speed is set to the second target idle speed . In the hybrid vehicle control device according to claim 1,
The control device for a hybrid vehicle, wherein the idle speed setting means sets the second target idle speed to a speed that is excluded from a resonance speed of the engine and the motor generator. In the hybrid vehicle control device according to claim 1 or 2,
The idle speed setting unit, when the motor slip drive control, sometimes there is protection request of the first engagement element, setting a target engine speed during idling of the engine to the second target idle speed A control apparatus for a hybrid vehicle characterized by the above.

Images