JP6202132B2 - Hybrid vehicle - Google Patents

Description

  The present invention relates to a hybrid vehicle, and more particularly to control of a hybrid vehicle including an internal combustion engine.

  In general, a variable valve operating device for changing the operating characteristics of an intake valve of an internal combustion engine is known. Some variable valve gears are configured such that at least one of the lift amount and the operating angle of the intake valve can be changed (see, for example, Patent Documents 1 to 6). By using the variable valve gear, it is possible to change the operating characteristics of the internal combustion engine.

  For example, Japanese Unexamined Patent Application Publication No. 2009-202662 (Patent Document 1) discloses a hybrid vehicle including a variable valve operating device. In this hybrid vehicle, when it is diagnosed that the variable valve operating device is out of order, the stop of the internal combustion engine is prohibited, and motor-assisted travel that travels using the outputs of both the internal combustion engine and the motor is executed. As a result, traveling performance can be ensured while avoiding poor starting of the internal combustion engine.

  There is also known a hybrid vehicle that travels by switching modes including a CD (Charge Depleting) mode that consumes an SOC (State Of Charge) of the power storage device and a CS (Charge Sustaining) mode that maintains the SOC (for example, And Patent Documents 7 and 8). In this hybrid vehicle, after the CD mode is selected until the SOC decreases to a predetermined amount, the CS mode is selected.

JP 2009-202662 A JP 2004-183610 A JP2013-53610A JP 2008-25550 A JP 2012-117376 A JP-A-9-242519 JP2013-129380A International Publication No. 2012/131944

  If the operating characteristics of the intake valve cannot be changed due to a malfunction of the variable valve system etc., the operating characteristics of the intake valve cannot be adjusted appropriately according to the operating conditions of the internal combustion engine, and the output of the internal combustion engine decreases. There is. In this case, since the power supplied from the power storage device to the motor is increased due to a decrease in the output of the internal combustion engine, it is difficult to maintain the SOC when the CS mode is selected. Therefore, there is a possibility that traveling performance cannot be secured due to a decrease in SOC during traveling in the CS mode.

  The present invention has been made to solve such problems, and an object of the present invention is to improve the operating characteristics of an intake valve in a hybrid vehicle having a variable valve operating device for changing the operating characteristics of the intake valve. It is to ensure the running performance when the desired operating characteristics cannot be changed.

  According to this invention, the hybrid vehicle includes an internal combustion engine, a power storage device, a rotating electrical machine, and a control device. The internal combustion engine has a variable valve gear for changing the operating characteristic of the intake valve. The power storage device can be charged. The rotating electrical machine receives a supply of electric power from the power storage device and generates a traveling driving force. The control device selects one of a CS (Charge Sustaining) mode that maintains the SOC of the power storage device within a predetermined range and a CD (Charge Depleting) mode that prioritizes consuming SOC compared to the CS mode. And for traveling. When the operating characteristic of the intake valve cannot be changed to a desired operating characteristic, the control device switches from the CD mode to the CS mode at a higher SOC than when the operating characteristic of the intake valve can be changed to the desired operating characteristic. As described above, the switching condition from the CD mode to the CS mode is changed.

  When the operating characteristic of the intake valve cannot be changed to a desired operating characteristic, the CS mode is switched to a higher SOC, so that the consumption of SOC in the CD mode is suppressed. Therefore, the deterioration of the running performance due to the decrease in SOC can be suppressed. Therefore, according to this hybrid vehicle, in a hybrid vehicle having a variable valve operating device for changing the operation characteristic of the intake valve, it is possible to ensure traveling performance when the operation characteristic of the intake valve cannot be changed to a desired operation characteristic. Can do.

  Preferably, when the SOC decreases to a predetermined SOC when the CD mode is selected, the control device switches the CD mode to the CS mode, and when the operating characteristic of the intake valve cannot be changed to a desired operating characteristic, The predetermined SOC is set higher than when the operating characteristic of the valve can be changed to a desired operating characteristic.

  According to this configuration, when the operating characteristic of the intake valve cannot be changed to a desired operating characteristic, the CS mode is switched to a higher SOC. Therefore, the deterioration of the running performance due to the decrease in SOC can be suppressed.

  Preferably, the control device switches to the CS mode when the operating characteristic of the intake valve cannot be changed to a desired operating characteristic when the CD mode is selected.

  According to this configuration, since the CS mode is immediately selected when the operating characteristic of the intake valve cannot be changed to a desired operating characteristic, it is possible to suppress the consumption of SOC in the CD mode.

  Preferably, the control device causes the CD mode to be switched from the CD mode to the CS mode at a higher SOC when the variable valve device is malfunctioning than when the variable valve device is normal. Change the switching condition from mode to CS mode.

  According to this configuration, it is possible to ensure traveling performance when the variable valve apparatus is out of order.

  Preferably, the control device makes a predetermined range when the operation characteristic of the intake valve cannot be changed to a desired operation characteristic wider than a predetermined range when the operation characteristic of the intake valve can be changed to a desired operation characteristic.

  According to this configuration, when the operating characteristic of the intake valve cannot be changed to a desired operating characteristic, the travel driving force of the rotating electric machine is allowed by allowing the SOC to vary more than when the operating characteristic of the intake valve can be changed to the desired operating characteristic. Can be used more easily. Therefore, the retreat travel that travels in a state where the output of the internal combustion engine is reduced can be executed flexibly.

  Preferably, the control device sets the center of the predetermined range when the operation characteristic of the intake valve cannot be changed to a desired operation characteristic to be equal to or more than the SOC at the time of switching from the CD mode to the CS mode.

  According to this configuration, the SOC in the CS mode can be maintained higher. As a result, deterioration in traveling performance can be suppressed by compensating for the decrease in the output of the internal combustion engine with the traveling driving force of the rotating electrical machine.

  Preferably, the variable valve operating apparatus has an operating characteristic of the intake valve as a first characteristic and a second characteristic having at least one of a lift amount and an operating angle larger than that when the operating characteristic is the first characteristic; It is configured to be switchable to any one of the third characteristics in which at least one of the lift amount and the operating angle is larger than when the operation characteristics are the second characteristics.

  According to this configuration, since the operation characteristics of the lift amount and the working angle of the intake valve are limited to three, it is possible to reduce the time required to adapt the control parameters for controlling the operating state of the engine. Furthermore, the configuration of the actuator can be simplified.

  Preferably, when the CD mode is selected, the control device switches to the CS mode when the operating characteristic of the intake valve cannot be changed from the first characteristic or the third characteristic to the desired operating characteristic.

  When the operating characteristic of the intake valve cannot be changed from the first characteristic or the third characteristic to a desired operating characteristic, there is a region where the output of the internal combustion engine tends to decrease. Therefore, since the CS mode is selected only when the operating characteristic of the intake valve cannot be changed from the first characteristic or the third characteristic to the desired operating characteristic, traveling in the CD mode is restricted more than necessary. This can be suppressed.

  Preferably, the variable valve operating apparatus has an operating characteristic of the intake valve as a first characteristic and a second characteristic having at least one of a lift amount and an operating angle larger than that when the operating characteristic is the first characteristic. It can be switched to either one.

  According to this configuration, since the operating characteristics of the lift amount and operating angle of the intake valve are limited to two, it is possible to further reduce the time required to adapt the control parameters for controlling the operating state of the engine. Furthermore, the configuration of the actuator can be further simplified.

  According to the present invention, in a hybrid vehicle having a variable valve operating device for changing the operation characteristic of the intake valve, it is possible to ensure traveling performance when the operation characteristic of the intake valve cannot be changed to a desired operation characteristic.

1 is a block diagram showing an overall configuration of a hybrid vehicle according to an embodiment of the present invention. It is a figure which shows the structure of the engine shown in FIG. It is a figure which shows the relationship between the valve lift implement | achieved in a VVL apparatus, and a crank angle. It is a front view of the VVL device which controls the lift amount and operating angle of the intake valve. It is the perspective view which showed the VVL apparatus partially. It is a graph explaining the difference in the engine torque by the characteristic of an intake valve. It is a functional block diagram of the control apparatus shown in FIG. It is a figure for demonstrating CD mode and CS mode. It is a figure which shows an example of the time change of SOC of the electrical storage apparatus in a comparative example. It is a figure which shows an example of the time change of SOC of the electrical storage apparatus in embodiment. It is a flowchart which shows the control structure of the traveling control which the control apparatus shown in FIG. 1 performs. It is a figure which shows the relationship between the valve lift and crank angle implement | achieved in the VVL apparatus which can change the operating characteristic of an intake valve in three steps. It is a figure which shows the operating line of an engine provided with the VVL apparatus which has the operating characteristic shown in FIG. It is a flowchart which shows the control structure of the traveling control which the control apparatus which controls the VVL apparatus which has the operating characteristic shown in FIG. 12 performs. It is a figure which shows the relationship between the valve lift and crank angle implement | achieved in the VVL apparatus which can change the operating characteristic of an intake valve in two steps. It is a flowchart which shows the control structure of the traveling control which the control apparatus by the modification 1 of embodiment of this invention performs. It is a flowchart which shows the control structure of the traveling control which the control apparatus by the modification 2 of embodiment of this invention performs. It is a flowchart which shows the control structure of the traveling control which the control apparatus by the modification 3 of embodiment of this invention performs.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  FIG. 1 is a block diagram showing an overall configuration of a hybrid vehicle according to an embodiment of the present invention. Referring to FIG. 1, hybrid vehicle 1 includes an engine 100, motor generators MG1 and MG2, a power split device 4, a speed reducer 5, drive wheels 6, a power storage device B, and a PCU (Power Control Unit). 20 and the control device 200.

  The hybrid vehicle 1 is a so-called plug-in hybrid vehicle. That is, hybrid vehicle 1 can travel with the driving force output from at least one of engine 100 and motor generator MG2, and can charge power storage device B with electric power supplied from system power supply 600 outside the vehicle. It is. Hereinafter, the power source outside the vehicle is also referred to as “external power source”, and the charging of power storage device B by the external power source is also referred to as “external charging”.

  Engine 100 and motor generators MG1, MG2 are connected through power split device 4. The driving force generated by the engine 100 is divided into two paths by the power split device 4. One is a path through which the driving force is transmitted to the driving wheel 6 via the speed reducer 5, and the other is a path through which the driving force is transmitted to the motor generator MG1.

  The power storage device B is a power storage element configured to be rechargeable. The power storage device B includes, for example, a secondary battery such as a lithium ion battery, a nickel metal hydride battery, or a lead storage battery, or a cell of a power storage element such as an electric double layer capacitor. Power storage device B is connected to PCU 20 for driving motor generators MG1, MG2. Then, the power storage device B supplies the PCU 20 with electric power for generating the driving force of the hybrid vehicle 1. Power storage device B stores the electric power generated by motor generators MG1 and MG2. The output of power storage device B is, for example, 200V. Power storage device B detects the voltage, current, and temperature of power storage device B and outputs the detected values to control device 200.

  PCU 20 converts the DC power supplied from power storage device B into AC power, and drives motor generators MG1, MG2. PCU 20 converts AC power generated by motor generators MG1 and MG2 into DC power and charges power storage device B.

  Hybrid vehicle 1 further includes a charging device 500, a charging port 510, and a relay 71 as a configuration for performing external charging.

  Charging port 510 is a power interface for receiving power from system power supply 600 outside the vehicle (hereinafter referred to as “external power”). Charging port 510 is configured to be connectable to connector 610 connected to system power supply 600 outside the vehicle.

  Charging device 500 is provided between charging port 510 and power storage device B. Charging device 500 is connected to power storage device B via relay 71. Based on a control signal from control device 200, charging device 500 converts external power (AC) input to charging port 510 into power (DC) that can charge power storage device B and outputs the power to power storage device B. . Thereby, power storage device B is charged by the external power.

  Control device 200 performs various controls such as mode control of hybrid vehicle 1, start / stop determination of engine 100, and charge / discharge control of power storage device B based on various sensor outputs. Control device 200 generates a control command value for controlling PCU 20, and outputs the generated control command value to PCU 20. Control device 200 generates a control command value for controlling engine 100, and outputs the generated control command value to engine 100. Control device 200 generates a signal for driving charging device 500 during external charging, and outputs the generated signal to charging device 500.

  FIG. 2 is a diagram showing a configuration of engine 100 shown in FIG. Referring to FIG. 2, engine 100 draws air from air cleaner 102. The intake air amount is adjusted by the throttle valve 104. The throttle valve 104 is an electrically controlled throttle valve that is driven by a throttle motor 312.

  The injector 108 injects fuel toward the intake port. Air mixed with fuel at the intake port is introduced into the cylinder 106.

  In the present embodiment, the engine 100 is described as a port injection engine in which the injection hole of the injector 108 is provided in the intake port. However, in addition to the injector 108 for port injection, fuel directly into the cylinder 106 is used. An injector for direct injection that injects fuel may be provided. Further, only a direct injection injector may be provided.

  The air-fuel mixture in the cylinder 106 is ignited by the spark plug 110 and burns. The air-fuel mixture after combustion, that is, the exhaust gas is purified by the three-way catalyst 112 and then discharged outside the vehicle. The piston 114 is pushed down by the combustion of the air-fuel mixture, and the crankshaft 116 rotates.

  An intake valve 118 and an exhaust valve 120 are provided at the top of the cylinder 106. The amount and timing of the air introduced into the cylinder 106 is controlled by the intake valve 118. The amount and timing of the exhaust gas discharged from the cylinder 106 is controlled by the exhaust valve 120. The intake valve 118 is driven by a cam 122. The exhaust valve 120 is driven by a cam 124.

  As will be described in detail later, intake valve 118 has its lift amount and operating angle controlled by a VVL (Variable Valve Lift) device 400. Note that the lift amount and the operating angle of the exhaust valve 120 may also be controlled. Further, a VVT (Variable Valve Timing) device for controlling the opening / closing timing may be combined with the VVL device 400.

  The control device 200 controls the throttle opening θth, the ignition timing, the fuel injection timing, the fuel injection amount, and the operation state of the intake valve (opening / closing timing, lift amount, working angle, etc.) so that the engine 100 is in a desired operation state. Control. Control device 200 receives signals from cam angle sensor 300, crank angle sensor 302, knock sensor 304, and throttle opening sensor 306.

  The cam angle sensor 300 outputs a signal representing the cam position. The crank angle sensor 302 outputs a signal representing the rotation speed of the crankshaft 116 (engine rotation speed) and the rotation angle of the crankshaft 116. Knock sensor 304 outputs a signal representing the intensity of vibration of engine 100. The throttle opening sensor 306 outputs a signal representing the throttle opening θth.

  FIG. 3 is a diagram showing the relationship between the valve displacement amount and the crank angle realized in the VVL device 400. Referring to FIG. 3, exhaust valve 120 opens and closes in the exhaust stroke, and intake valve 118 opens and closes in the intake stroke. The valve displacement amount of the exhaust valve 120 is shown in the waveform EX, while the valve displacement amount of the intake valve 118 is shown in the waveforms IN1 and IN2.

  The valve displacement is the displacement of the intake valve 118 from the state where the intake valve 118 is closed. The lift amount is a valve displacement amount when the opening degree of the intake valve 118 reaches a peak. The operating angle is a crank angle from when the intake valve 118 is opened until it is closed.

  The operating characteristic of the intake valve 118 is changed between the waveforms IN1 and IN2 by the VVL device 400. A waveform IN1 shows a case where the lift amount and the working angle are minimum. A waveform IN2 shows a case where the lift amount and the working angle are maximum. In the VVL device 400, the operating angle increases as the lift amount increases.

  FIG. 4 is a front view of a VVL device 400 that is an example of a device that controls the lift amount and the operating angle of the intake valve 118. Referring to FIG. 4, VVL device 400 includes drive shaft 410 that extends in one direction, support pipe 420 that covers the outer peripheral surface of drive shaft 410, and the axial direction of drive shaft 410 on the outer peripheral surface of support pipe 420. The input arm 430 and the swing cam 440 are provided. An actuator (not shown) that linearly moves the drive shaft 410 is connected to the tip of the drive shaft 410.

  The VVL device 400 is provided with one input arm 430 corresponding to one cam 122 provided in each cylinder. Two swing cams 440 are provided on both sides of the input arm 430 corresponding to the pair of intake valves 118 provided in each cylinder.

  The support pipe 420 is formed in a hollow cylindrical shape and is disposed in parallel to the camshaft 130. The support pipe 420 is fixed to the cylinder head so as not to move or rotate in the axial direction.

  A drive shaft 410 is inserted into the support pipe 420 so as to be slidable in the axial direction. On the outer peripheral surface of the support pipe 420, an input arm 430 and two swing cams 440 are provided so as to be swingable about the axis of the drive shaft 410 and not to move in the axial direction.

  The input arm 430 includes an arm portion 432 that protrudes in a direction away from the outer peripheral surface of the support pipe 420, and a roller portion 434 that is rotatably connected to the tip of the arm portion 432. The input arm 430 is provided such that the roller portion 434 is disposed at a position where the roller portion 434 can contact the cam 122.

  The swing cam 440 has a substantially triangular nose portion 442 that protrudes away from the outer peripheral surface of the support pipe 420. A cam surface 444 that is curved in a concave shape is formed on one side of the nose portion 442. A roller attached rotatably to the rocker arm 128 is pressed against the cam surface 444 by a biasing force of a valve spring provided on the intake valve 118.

  The input arm 430 and the swing cam 440 integrally swing about the axis of the drive shaft 410. For this reason, when the camshaft 130 rotates, the input arm 430 in contact with the cam 122 swings, and the swing cam 440 swings in conjunction with the movement of the input arm 430. The movement of the swing cam 440 is transmitted to the intake valve 118 via the rocker arm 128, and the intake valve 118 is opened and closed.

  The VVL device 400 further includes a device that changes the relative phase difference between the input arm 430 and the swing cam 440 around the axis of the support pipe 420. The lift amount and operating angle of the intake valve 118 are appropriately changed by a device that changes the relative phase difference.

  That is, if the relative phase difference between the two is increased, the swing angle of the rocker arm 128 with respect to the swing angle of the input arm 430 and the swing cam 440 is increased, and the lift amount and the operating angle of the intake valve 118 are increased.

  If the relative phase difference between the two is reduced, the swing angle of the rocker arm 128 with respect to the swing angle of the input arm 430 and the swing cam 440 is reduced, and the lift amount and the operating angle of the intake valve 118 are reduced.

  FIG. 5 is a perspective view partially showing the VVL device 400. In FIG. 5, a part is broken and shown so that the internal structure can be clearly understood.

  Referring to FIG. 5, a space defined between input arm 430 and two swing cams 440 and the outer peripheral surface of support pipe 420 is rotatable with respect to support pipe 420 and is axial. The slider gear 450 is slidably supported in the housing. The slider gear 450 is slidable in the axial direction on the support pipe 420.

  The slider gear 450 is provided with a helical gear 452 having a right-hand spiral helical spline formed at the center in the axial direction. Each slider gear 450 is provided with a helical gear 454 that is located on both sides of the helical gear 452 and has a left-hand spiral helical spline formed opposite to the helical gear 452.

  On the other hand, helical splines corresponding to the helical gears 452 and 454 are formed on the inner peripheral surfaces of the input arm 430 and the two swing cams 440 that define the space in which the slider gear 450 is accommodated, respectively. In other words, the input arm 430 is formed with a right-hand spiral helical spline, and the helical spline meshes with the helical gear 452. Further, the swing cam 440 is formed with a left-handed helical helical spline, and the helical spline meshes with the helical gear 454.

  The slider gear 450 is formed with a long hole 456 extending between the one helical gear 454 and the helical gear 452 and extending in the circumferential direction. Although not shown, the support pipe 420 is formed with an elongated hole extending in the axial direction so as to overlap a part of the elongated hole 456. The drive shaft 410 inserted into the support pipe 420 is integrally provided with a locking pin 412 that projects through the elongated hole 456 and a portion where the elongated hole (not shown) overlaps.

  When the drive shaft 410 moves in the axial direction by an actuator (not shown) connected to the drive shaft 410, the slider gear 450 is pushed by the locking pin 412, and the helical gears 452 and 454 are simultaneously moved in the axial direction of the drive shaft 410. Moving. In response to the movement of the helical gears 452 and 454, the input arm 430 and the swing cam 440 that are spline-engaged with them do not move in the axial direction. Therefore, the input arm 430 and the swing cam 440 rotate around the axis of the drive shaft 410 through the meshing of the helical spline.

  At this time, the input arm 430 and the swing cam 440 have the opposite directions of the formed helical spline. Therefore, the rotation directions of the input arm 430 and the swing cam 440 are opposite to each other. As a result, the relative phase difference between the input arm 430 and the swing cam 440 changes, and the lift amount and operating angle of the intake valve 118 are changed as described above. The VVL device is not limited to this type. For example, a VVL device that electrically drives a valve or a VVL device that drives a valve using hydraulic pressure may be used.

  The control device 200 controls the lift amount and operating angle of the intake valve 118 by adjusting the operation amount of the actuator that linearly moves the drive shaft 410.

  FIG. 6 is a graph for explaining the difference in engine torque due to the characteristics of the intake valve 118. In FIG. 6, the horizontal axis represents the engine speed, and the vertical axis represents the engine torque. In FIG. 6, the solid line indicates a case where the lift amount and the operating angle are small, and the broken line indicates a case where the lift amount and the operating angle are large.

  Referring to FIG. 6, in the region where the engine speed is low, the engine torque that can be output is larger than when the lift amount and the operating angle are small. When the lift amount and the operating angle are large, a part of the air sucked into the cylinder is returned to the outside of the cylinder. On the other hand, when the lift amount and the operating angle are small, the intake valve 118 is closed early, so that more air can be introduced, and the torque that can be output from the engine 100 increases.

  On the other hand, in the region where the engine speed is high, the engine torque that can be output is larger than when the lift amount and the operating angle are large. This is because when the lift amount and the operating angle are large, more air can be introduced using the inertial force of the air.

  FIG. 7 is a functional block diagram of the control device 200 shown in FIG. Each functional block described in the functional block diagram of FIG. 7 is realized by hardware or software processing by the control device 200.

  Referring to FIG. 7, control device 200 includes valve operating control unit 210, SOC calculation unit 220, external charge control unit 230, mode control unit 240, charge / discharge control unit 250, and travel control unit 260. including.

  Valve controller 210 controls VVL device 400 so as to determine at least one of the lift amount and operating angle of intake valve 118 in accordance with the rotational speed and load of engine 100. The valve control unit 210 outputs a signal VLV for controlling the VVL device 400 to the VVL device 400.

  Further, the valve control unit 210 determines that the lift amount and the operating angle of the intake valve 118 cannot be changed. The state in which the lift amount and operating angle of intake valve 118 cannot be changed is a state in which the lift amount and operating angle of intake valve 118 cannot be changed by VVL device 400. When the lift amount and operating angle of intake valve 118 cannot be changed, the lift amount and operating angle of intake valve 118 are set to desired operating characteristics by VVL device 400 (for example, operating characteristics required for intake valve 118). Including states that cannot be changed.

  As an example, the valve controller 210 can determine that the lift amount and the operating angle of the intake valve 118 cannot be changed when the VVL device 400 fails. Further, the valve control unit 210 determines that the lift amount and the operating angle of the intake valve 118 cannot be changed when the operating capability of the VVL device 400 decreases due to a decrease in temperature (for example, at a very low temperature). Also good. The valve control unit 210 sends a signal indicating that the lift amount and operating angle of the intake valve 118 cannot be changed, and a signal indicating the lift amount and operating angle of the intake valve 118 that cannot be changed to the mode control unit 240. Output.

  SOC calculation unit 220 calculates an SOC indicating the state of charge of power storage device B based on voltage Vb and current Ib of power storage device B detected by a sensor (not shown). This SOC represents the amount of power stored in the fully charged state of the power storage device B in 0 to 100%, and indicates the remaining power storage of the power storage device B. Various known methods can be used for calculating the SOC.

  When an external power supply is connected to charging port 510 (FIG. 1), external charging control unit 230 controls to drive charging device 500 based on input voltage Vac and input current Iac detected by a sensor (not shown). A signal is generated and output to the charging device 500. Then, when the SOC of power storage device B received from SOC calculation unit 220 reaches a predetermined upper limit value, external charge control unit 230 ends charge control and outputs a charge end signal indicating the end of charge to mode control unit 240. .

  Mode control unit 240 selects a mode of hybrid vehicle 1 based on the SOC calculated by SOC calculation unit 220 and the signal received from valve operating control unit 210. Specifically, mode control unit 240 selects either the CS mode that maintains the SOC of power storage device B within a predetermined range or the CD mode that prioritizes consuming SOC as compared to CS mode. Set.

  FIG. 8 is a diagram for explaining the CD mode and the CS mode. Referring to FIG. 8, it is assumed that after power storage device B is fully charged by external charging (SOC = MAX), traveling is started in the CD mode.

  The CD mode is a mode that consumes SOC, and basically consumes electric power (mainly electric energy by external charging) stored in the power storage device B. When traveling in the CD mode, engine 100 does not operate in order to maintain the SOC. As a result, the SOC may temporarily increase due to the regenerative power collected when the vehicle is decelerated or the power generated by the operation of the engine 100, but as a result, the rate of discharge is higher than the charge. As a whole, the SOC decreases as the travel distance increases.

  The CS mode is a mode for maintaining the SOC within a predetermined range. As an example, when the SOC decreases to a predetermined value Stg indicating a decrease in SOC at time t1, the CS mode is selected, and the subsequent SOC is maintained within a predetermined range. Specifically, engine 100 operates when SOC decreases, and engine 100 stops when SOC increases. That is, in CS mode, engine 100 operates to maintain the SOC. Although not particularly illustrated, a switch that can be operated by the driver may be provided so that the mode can be switched according to the driver's intention regardless of the decrease in the SOC.

  In this hybrid vehicle 1, when the traveling power is smaller than a predetermined engine start threshold value, engine 100 is stopped and the vehicle is driven by motor generator MG2 (EV traveling). On the other hand, when the traveling power exceeds the engine start threshold, the engine 100 is operated to travel (HV traveling). In HV traveling, hybrid vehicle 1 travels using the driving force of engine 100 in addition to the driving force of motor generator MG2 or instead of motor generator MG2. The electric power generated by motor generator MG1 due to the operation of engine 100 is directly supplied to motor generator MG2 or stored in power storage device B.

  Here, the engine start threshold value in the CD mode is larger than the engine start threshold value in the CS mode. That is, the region in which the hybrid vehicle 1 travels in the EV mode in the CD mode is larger than the region in which the hybrid vehicle 1 travels in the EV mode in the CS mode. Thereby, in the CD mode, the frequency at which engine 100 is started is suppressed. On the other hand, in CS mode, control is performed so that hybrid vehicle 1 travels efficiently using both engine 100 and motor generator MG2.

  Even in the CD mode, the engine 100 operates if the running power exceeds the engine start threshold value. Even if the traveling power does not exceed the engine start threshold value, the operation of engine 100 may be permitted, for example, when warm water heating using engine 100 as a heat source is required or when engine 100 is warmed up. On the other hand, even in the CS mode, the engine 100 stops when the SOC increases. That is, the CD mode is not limited to EV traveling that travels while the engine 100 is always stopped, and the CS mode is not limited to HV traveling that travels while the engine 100 is always operated. In both the CD mode and the CS mode, EV running and HV running are possible.

  FIG. 9 is a diagram illustrating an example of a time change in SOC of the power storage device in the comparative example. Referring to FIG. 9, the solid line shows an example of the time change of the SOC when the operation characteristic of the intake valve 118 can be changed, and the broken line shows the time change of the SOC when the operation characteristic of the intake valve 118 cannot be changed. An example is shown.

  When the operating characteristic of intake valve 118 can be changed, the SOC is maintained near predetermined value Stg in the CS mode. On the other hand, if the operating characteristic of intake valve 118 cannot be changed due to a failure or the like, the SOC may not be maintained in the vicinity of predetermined value Stg in the CS mode.

  Specifically, when the operating characteristics of the intake valve 118 cannot be changed due to a failure or the like, the output of the engine 100 may decrease. For example, as shown in FIG. 6, when the lift amount and operating angle of the intake valve 118 are large, the torque that can be output on the low rotation side is lower than when the lift amount and operating angle of the intake valve 118 are small. To do. On the other hand, when the lift amount and operating angle of intake valve 118 are small, the torque that can be output on the high rotation side is lower than when the lift amount and operating angle of intake valve 118 are large.

  In this case, since the power supplied from power storage device B to motor generator MG2 increases due to the decrease in the output of engine 100, it is difficult to maintain the SOC when the CS mode is selected. Therefore, there is a possibility that traveling performance cannot be ensured when the SOC decreases to near the lower limit during traveling in the CS mode.

  In the present embodiment, when at least one of the lift amount and the working angle of the intake valve 118 cannot be changed, the CD mode is set to the CS mode more than when at least one of the lift amount and the working angle of the intake valve 118 is changeable. Control is performed to change the switching condition for switching to the mode so as to easily switch to the CS mode. As a result, the SOC when the CS mode is started is increased to ensure traveling performance.

  Specifically, as shown in FIG. 10, when the mode control unit 240 is traveling in the CD mode, when at least one of the lift amount and the operating angle of the intake valve 118 can be changed, When the SOC falls below a predetermined value X, the CS mode is selected. On the other hand, when the vehicle is traveling in the CD mode, the mode control unit 240 sets the predetermined value Y larger than the predetermined value X to SOC if at least one of the lift amount and the operating angle of the intake valve 118 cannot be changed. When CS falls below, CS mode is selected. Mode control unit 240 outputs a signal indicating the selected mode to charge / discharge control unit 250 and travel control unit 260.

  Charging / discharging control unit 250 receives the SOC of power storage device B from SOC calculation unit 220 and receives a signal indicating the mode from mode control unit 240. When the CS mode is selected, charge / discharge control unit 250 controls the charge / discharge amount of power storage device B so as to maintain the SOC at a predetermined target value based on these signals.

  Specifically, the charge / discharge control unit 250 maintains the SOC at a predetermined value X when at least one of the lift amount and the working angle of the intake valve 118 can be changed, and the charge / discharge control unit 250 When at least one of the lift amount and the working angle of 118 cannot be changed, the charge / discharge request amount of the power storage device B is calculated so as to maintain the SOC at the predetermined value Y. The charge / discharge control unit 250 outputs the calculated charge / discharge request amount to the travel control unit 260.

  Traveling control unit 260 controls PCU 20 and engine 100 based on the mode, the required charge / discharge amount, and the required driving force from the driver. Specifically, when the mode is the CD mode, since the SOC is not maintained, basically, motor generator MG2 is driven by the energy output from power storage device B based on the required driving force.

  On the other hand, when the mode is the CS mode, the outputs of engine 100 and power storage device B are controlled so as to maintain the SOC. Specifically, the traveling control unit 260 calculates the required engine power based on the required charge / discharge amount and the required driving force. Traveling control unit 260 controls engine 100 based on the required engine power and also controls the output of motor generator MG2 based on the required driving force.

  FIG. 11 is a flowchart showing a control structure of travel control executed by control device 200 shown in FIG. The flowchart shown in FIG. 11 is realized by executing a program stored in advance in the control device 200 at a predetermined cycle. Alternatively, for some steps, it is also possible to construct dedicated hardware (electronic circuit) and realize processing (the same applies to the flowcharts shown in FIGS. 14 and 16 described below). .

  Referring to FIG. 11, control device 200 determines whether or not the CD mode is selected in step (hereinafter, step is abbreviated as S) 100. If it is determined that the CD mode is not selected (NO in S100), control device 200 waits until the CD mode is selected.

  If it is determined that the CD mode is selected (YES in S100), control device 200 determines whether or not the lift amount and operating angle of intake valve 118 cannot be changed (S110). When it is determined that the lift amount and operating angle of intake valve 118 can be changed (NO in S110), control device 200 sets a threshold value for switching the CD mode to the CS mode to a predetermined value X. (S120). When it is determined that the lift amount and operating angle of intake valve 118 cannot be changed (YES in S110), control device 200 sets a threshold value for switching the CD mode to the CS mode to a value greater than predetermined value X. A large predetermined value Y is set (S130).

  Subsequently, in S140, control device 200 determines whether or not the SOC of power storage device B is smaller than the threshold value. If it is determined that the SOC of power storage device B is smaller than the threshold value (YES in S140), control device 200 selects the CS mode (S150). If it is determined that the SOC of power storage device B is equal to or greater than the threshold value (NO in S140), control device 200 maintains the CD mode (S160).

  As described above, in this embodiment, when at least one of the lift amount and the working angle of the intake valve 118 cannot be changed, at least one of the lift amount and the working angle of the intake valve 118 can be changed. The switching condition from the CD mode to the CS mode is changed so that the switching from the CD mode to the CS mode is performed at a higher SOC. When at least one of the lift amount and the operating angle of intake valve 118 cannot be changed, the output of engine 100 may decrease. When the output of engine 100 decreases, the traveling drive force of motor generator MG2 increases in order to satisfy the required traveling drive force. Therefore, since the electric power supplied from power storage device B to motor generator MG2 increases, there is a possibility that the SOC cannot be maintained in the CS mode.

  When at least one of the lift amount and operating angle of intake valve 118 cannot be changed, the mode is switched to the CS mode at a higher SOC, so that the consumption of SOC in the CD mode is suppressed. Therefore, the deterioration of the running performance due to the decrease in SOC can be suppressed. Therefore, according to this embodiment, in a hybrid vehicle having a variable valve system for changing the operating characteristic of intake valve 118, the running performance when the operating characteristic of intake valve 118 cannot be changed to a desired operating characteristic is improved. Can be secured.

  Further, in this embodiment, when the CD mode is selected, when the SOC decreases to a predetermined SOC, the CD mode is switched to the CS mode, and at least one of the lift amount and the operating angle of the intake valve 118 cannot be changed. In this case, the predetermined SOC is made higher than when at least one of the lift amount and the operating angle of the intake valve 118 can be changed. Thus, when at least one of the lift amount and the operating angle of the intake valve 118 cannot be changed, the mode is switched to the CS mode at a higher SOC. Therefore, the deterioration of the running performance due to the decrease in SOC can be suppressed.

  In this embodiment, when the VVL device 400 is out of order, the CD mode is switched to the CS mode at a higher SOC than when the VVL device 400 is normal. The switching condition from the mode to the CS mode may be changed. In this case, it is possible to ensure the running performance when the VVL device 400 is out of order.

  Note that the lift amount and operating angle of the intake valve 118 may be changed continuously (steplessly) or discretely (stepwise).

  FIG. 12 is a diagram showing the relationship between the valve displacement amount and the crank angle realized in the VVL device 400A that can change the operation characteristic of the intake valve 118 in three stages. The VVL device 400A is configured to be able to change the operation characteristic to any one of the first to third characteristics. The first characteristic is indicated by the waveform IN1a. The second characteristic is indicated by a waveform IN2a, and the lift amount and the operating angle are larger than when the operating characteristic is the first characteristic. The third characteristic is indicated by a waveform IN3a, and the lift amount and the working angle are larger than when the operating characteristic is the second characteristic.

  FIG. 13 is a diagram showing an operating line of engine 100A including VVL device 400A having the operating characteristics shown in FIG. In FIG. 13, the horizontal axis indicates the engine speed, and the vertical axis indicates the engine torque. In addition, the dashed-dotted line in FIG. 13 shows the torque characteristic corresponding to the 1st-3rd characteristic (IN1a-IN3a). Further, a circle represented by a solid line in FIG. 13 represents an iso-fuel consumption line. The equal fuel consumption line is a line connecting points where fuel consumption is equal, and the closer to the center of the circle, the better the fuel consumption. It is assumed that engine 100A is basically operated on an engine operating line represented by a solid line in FIG.

  Here, in the low rotation range indicated by the region R1, it is important to reduce the shock when starting the engine. In addition, the introduction of EGR (Exhaust Gas Recirculation) gas is stopped, and fuel efficiency is improved by the Atkinson cycle. Therefore, the third characteristic (IN3a) is selected as the operation characteristic of the intake valve 118 so that the lift amount and the operating angle are increased. In the middle rotation range indicated by the region R2, fuel efficiency is improved by increasing the amount of EGR gas introduced. Therefore, the second characteristic (IN2a) is selected as the operation characteristic of the intake valve 118 so that the lift amount and the operating angle are intermediate.

  That is, when the lift amount and the operating angle of the intake valve 118 are large (third characteristic), the improvement in fuel consumption by the Atkinson cycle is prioritized over the improvement in fuel consumption by introduction of EGR gas. On the other hand, when an intermediate lift amount and operating angle are selected (second characteristic), priority is given to improving fuel efficiency by introducing EGR gas over improving fuel efficiency by the Atkinson cycle.

  In the high rotation range indicated by the region R3, a large amount of air is introduced into the cylinder by the intake inertia, and the output performance is improved by increasing the actual compression ratio. Therefore, the third characteristic (IN3a) is selected as the operation characteristic of the intake valve 118 so that the lift amount and the operating angle are increased.

  In addition, when engine 100A is operated at a high load in a low rotation range, when engine 100A is started at an extremely low temperature, or when the catalyst is warmed up, intake valve 118 is set so that the lift amount and the operating angle become small. The first characteristic (IN1a) is selected as the operating characteristic. Thus, the lift amount and the operating angle are determined according to the operating state of engine 100A.

  FIG. 14 is a flowchart showing a control structure of travel control executed by control device 200A that controls VVL device 400A having the operating characteristics shown in FIG. Referring to FIG. 14, S100 and S120 to S160 are the same as those in the flowchart shown in FIG.

  If it is determined in S100 that the CD mode is selected (YES in S100), control device 200A determines that the operation characteristic of intake valve 118 is the first characteristic (IN1a) or the third characteristic (IN3a). ) Is determined (S115). That is, the control device 200A determines whether or not the operating characteristic of the intake valve 118 cannot be changed from the first characteristic (IN1a) or the third characteristic (IN3a).

  If it is determined that the operating characteristic of intake valve 118 is not fixed to either the first characteristic (IN1a) or the third characteristic (IN3a) (NO in S115), control device 200A operates in the CD mode. Is set to a predetermined value X for switching to the CS mode (S120). When it is determined that the operating characteristic of intake valve 118 is fixed to the first characteristic (IN1a) or the third characteristic (IN3a) (YES in S115), control device 200A changes the CD mode to the CS mode. The threshold value for switching to is set to a predetermined value Y larger than the predetermined value X (S130).

  In such a configuration, the operating characteristics of the lift amount and the operating angle of the intake valve 118 are limited to three, so that the operation of the engine 100 is performed as compared with the case where the lift amount and the operating angle of the intake valve 118 continuously change. The time required for adaptation of control parameters for controlling the state can be reduced. Furthermore, since the torque required for the actuator for changing the lift amount and operating angle of the intake valve 118 is reduced, the actuator can be reduced in size and weight. For this reason, the manufacturing cost of an actuator can be reduced.

  In addition, there is a region where the output of engine 100 tends to decrease when the operating characteristic of intake valve 118 is fixed to either the first characteristic or the third characteristic. Therefore, since the CS mode is selected only when the operation characteristic of the intake valve 118 is fixed to either the first characteristic or the third characteristic, it is possible to prevent the driving in the CD mode from being restricted more than necessary. can do.

  FIG. 15 is a diagram showing the relationship between the valve displacement amount and the crank angle realized in the VVL device 400B that can change the operation characteristic of the intake valve 118 in two stages. The VVL device 400B is configured to be able to change the operation characteristic to one of the first and second characteristics. The first characteristic is indicated by the waveform IN1b. The second characteristic is indicated by a waveform IN2b, and the lift amount and the operating angle are larger than when the operating characteristic is the first characteristic.

  In such a configuration, since the operating characteristics of the lift amount and the working angle of the intake valve 118 are limited to two, it is possible to further reduce the time required to adapt the control parameters for controlling the operating state of the engine 100. it can. Furthermore, the configuration of the actuator can be further simplified. The operating characteristics of the lift amount and the operating angle of the intake valve 118 are not limited to being changed to two steps or three steps, and may be changed to any step of four steps or more.

[Modification 1]
FIG. 16 is a flowchart showing a control structure of travel control executed by control device 200B according to the first modification of the embodiment of the present invention. In addition, the other structure of the control apparatus 200B by the modification 1 of embodiment is the same as that of embodiment.

  Referring to FIG. 16, control device 200B determines whether or not the CD mode is selected in S200. If it is determined that the CD mode is not selected (NO in S200), control device 200B waits until the CD mode is selected.

  When it is determined that the CD mode is selected (YES in S200), control device 200B determines whether or not the lift amount and operating angle of intake valve 118 cannot be changed (S210). When it is determined that the lift amount and the operating angle of intake valve 118 cannot be changed (YES in S210), control device 200B selects CS mode (S220).

  If it is determined that the lift amount and operating angle of intake valve 118 can be changed (NO in S210), control device 200B determines whether or not the SOC of power storage device B is smaller than the threshold value. (S230). If it is determined that the SOC of power storage device B is smaller than the threshold value (YES in S230), control device 200B selects the CS mode (S220). If it is determined that the SOC of power storage device B is equal to or greater than the threshold value (NO in S230), control device 200B maintains the CD mode (S240).

  As described above, in the first modification of the present embodiment, when the CD mode is selected, when at least one of the lift amount and the operating angle of the intake valve 118 cannot be changed, the mode is switched to the CS mode. Therefore, the CS mode is immediately selected when at least one of the lift amount and the operating angle of the intake valve 118 cannot be changed, so that the consumption of SOC in the CD mode can be suppressed.

[Modification 2]
FIG. 17 is a flowchart showing a control structure of travel control executed by control device 200C according to the second modification of the embodiment of the present invention. In addition, the other structure of 200 C of control apparatuses by the modification 2 of embodiment is the same as that of embodiment.

  Referring to FIG. 17, S100 to S120, S130, and S140 to S160 are the same as those in the embodiment, and therefore description thereof will not be repeated. When the threshold value for switching the CD mode to the CS mode is set to predetermined value X in S120, control device 200C sets the SOC control range to predetermined range R1 (S121). The SOC control range is a range in which the SOC is maintained in the CS mode. Control device 200C controls the charge / discharge amount of power storage device B so as to maintain the SOC within the set control range.

  When the threshold value for switching the CD mode to the CS mode is set to predetermined value Y in S130, control device 200C sets the SOC control range to a predetermined range R2 wider than predetermined range R1 (S131). . As a result, when at least one of the lift amount and the operating angle of intake valve 118 cannot be changed, the restriction that arises in order to maintain the SOC within the control range in the CS mode is relaxed. Therefore, by actively using the charging / discharging capability of power storage device B, the traveling driving force of motor generator MG2 can be more easily utilized.

  As described above, in Modification 2 of this embodiment, control device 200C maintains the SOC of power storage device B within a predetermined range in the CS mode, and at least one of the lift amount and working angle of intake valve 118 Is made wider than the predetermined range when at least one of the lift amount and the operating angle of the intake valve 118 is changeable.

  Thus, when at least one of the lift amount and the working angle of the intake valve 118 cannot be changed, the variation of the SOC is allowed more than when at least one of the lift amount and the working angle of the intake valve 118 is changeable. The travel driving force of motor generator MG2 can be made easier to use. Therefore, the retreat travel that travels in a state where the output of the engine 100 is reduced can be executed flexibly.

[Modification 3]
FIG. 18 is a flowchart showing a control structure of travel control executed by control device 200D according to the third modification of the embodiment of the present invention. In addition, the other structure of control apparatus 200D by the modification 3 of embodiment is the same as that of embodiment.

  Referring to FIG. 17, S100 to S120, S130, and S140 to S160 are the same as those in the embodiment, and therefore description thereof will not be repeated. When the threshold value for switching the CD mode to the CS mode is set to predetermined value X in S120, control device 200D sets the control center of the SOC to predetermined value C1 (S122). As an example, a threshold value (predetermined value X) is set as the predetermined value C1. The SOC control center is the center of the range in which the SOC is maintained in the CS mode. Control device 200D controls the charge / discharge amount of power storage device B so that the center of the range in which the SOC is maintained becomes the set control center.

  When the threshold value for switching the CD mode to the CS mode is set to a predetermined value Y in S130, control device 200D determines a predetermined value that is equal to or greater than the threshold value (predetermined value Y) at the SOC control center. Set to C2 (S132). That is, the control center is set to a value equal to or higher than the SOC at the time of switching from the CD mode to the CS mode. Thereby, SOC in CS mode can be maintained higher.

  As described above, in Modification 3 of this embodiment, control device 200D maintains the SOC of power storage device B within a predetermined range in the CS mode, and at least one of the lift amount and working angle of intake valve 118 The center of the predetermined range when the value cannot be changed is equal to or more than the SOC at the time of switching from the CD mode to the CS mode.

  Thereby, SOC in CS mode can be maintained higher. As a result, deterioration in traveling performance can be suppressed by compensating for the decrease in the output of engine 100 with the traveling driving force of motor generator MG2.

  In the above embodiment, the case where the operating angle is changed together with the lift amount of the intake valve 118 has been described. However, the present invention can also be applied to a configuration in which only the lift amount of the intake valve 118 can be changed. Yes, the present invention can be applied to a configuration in which only the operating angle of the intake valve 118 can be changed. Even in a configuration in which either the lift amount or the working angle of the intake valve 118 can be changed, the same effect as in the case where both the lift amount and the working angle of the intake valve 118 can be changed can be obtained. A configuration in which either the lift amount or the operating angle of the intake valve 118 can be changed can be realized by using a known technique.

  In the above-described embodiment, the series / parallel type hybrid vehicle has been described in which the power split device 4 can divide and transmit the power of the engine 100 to the drive wheels 6 and the motor generators MG1, MG2. The invention is also applicable to other types of hybrid vehicles. That is, for example, a so-called series-type hybrid vehicle that uses the engine 100 only to drive the motor generator MG1 and generates the driving force of the vehicle only by the motor generator MG2, or regenerative energy among the kinetic energy generated by the engine 100 The present invention can also be applied to a hybrid vehicle in which only the electric energy is recovered, a motor assist type hybrid vehicle in which a motor assists the engine as the main power if necessary. The present invention can also be applied to a hybrid vehicle that travels with the power of only the engine with the motor disconnected.

  The method of supplying power from system power supply 600 to charging port 510 is not limited to the contact-type power transmission method in which connector 610 connected to system power supply 600 is in contact with charging port 510. For example, a non-contact power transmission method such as power transmission using electromagnetic induction, power transmission using electromagnetic waves, or power transmission using a so-called resonance method may be used.

  In the above, engine 100 corresponds to an embodiment of “internal combustion engine” in the present invention, and motor generator MG2 corresponds to an embodiment of “rotating electric machine” in the present invention. VVL device 400 corresponds to an example of a “variable valve operating device” in the present invention.

  Although the embodiment of the present invention and Modifications 1 to 3 have been described above, the configurations of the embodiment and Modifications 1 to 3 may be combined as appropriate.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Hybrid vehicle, 4 Power split device, 5 Reducer, 6 Drive wheel, 20 PCU, 71 Relay, 100 Engine, 102 Air cleaner, 104 Throttle valve, 106 Cylinder, 108 Injector, 110 Spark plug, 112 Three way catalyst, 114 Piston , 116 Crankshaft, 118 Intake valve, 120 Exhaust valve, 122,124 Cam, 128 Rocker arm, 130 Camshaft, 200 Controller, 210 Valve control unit, 220 SOC calculation unit, 230 External charge control unit, 240 Mode control unit , 250 charge / discharge control unit, 260 travel control unit, 300 cam angle sensor, 302 crank angle sensor, 304 knock sensor, 306 throttle opening sensor, 312 throttle motor, 400 VVL device, 410 Moving shaft, 412 Locking pin, 420 Support pipe, 430 Input arm, 432 Arm part, 434 Roller part, 440 Oscillating cam, 442 Nose part, 444 Cam surface, 450 Slider gear, 452, 454 Helical gear, 456 Long hole, 500 Charging device, 510 charging port, 600 system power supply, 610 connector, B power storage device, MG1, MG2 motor generator.

Claims (1)

An internal combustion engine having a variable valve system for changing the operating characteristics of the intake valve;
A rechargeable power storage device;
A rotating electrical machine that receives a supply of electric power from the power storage device and generates a driving force;
Select either a CS (Charge Sustaining) mode that maintains the SOC of the power storage device within a predetermined range, or a CD (Charge Depleting) mode that prioritizes consuming the SOC compared to the CS mode. And a control device for traveling
In the CS mode, it is possible to switch between EV traveling that travels by the rotating electrical machine with the internal combustion engine stopped, and HV traveling that travels by operating the internal combustion engine,
When the CD mode is selected, the control device switches to the CS mode when the operation characteristic of the intake valve cannot be changed to a desired operation characteristic.

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