JP2015116959A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle incorporated with a variable valve device and an internal combustion engine with a smaller delay in response even during catalyst warm-up period.SOLUTION: A control apparatus 200 performs: executing first control (first warm-up control) for warming up a catalyst 112S rapidly when a catalyst warm-up is requested; then executing second control (second warm-up control) with an output of an engine 100 as a given value; controlling, when the catalyst warm-up is completed, the engine 100 by executing third control for controlling a VVL device 400 on the basis of a revolution speed of the engine 100 and required torque; and controlling, during executing the second control, the VVL device 400 so that, while suppressing the output of the engine 100 to the given value, at least one maximum value of an amount of lift and working angle of an intake valve 118 is decreased proportionately with a magnitude of a required output and controlling a motor so as to share an amount of change of the required output.

Description

  The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle including an internal combustion engine that includes a variable valve operating device for changing the operating characteristics of an intake valve.

  In order to purify exhaust gas from an internal combustion engine, a purification device including a catalyst is used. In order for the catalyst to fully exhibit the purification function, it is necessary to raise the temperature of the catalyst.

  For example, Japanese Patent Laying-Open No. 2012-40915 (Patent Document 1) discloses that in a hybrid vehicle equipped with an internal combustion engine, when a catalyst warm-up request is requested, first, the first operation point (for rapid catalyst warm-up) that retards the ignition timing. ), The internal combustion engine is operated. When the temperature at the catalyst end increases, the ignition timing is returned, and the internal combustion engine is operated at the second operation point at which the required output to the internal combustion engine is fixed. When the warm-up of the catalyst is completed, the normal output is changed to change the required output for the internal combustion engine based on the required output for the entire vehicle.

JP 2012-40915 A JP 2012-81886 A

  When the internal combustion engine is operated at the second operation point with the required output (Pe) for the internal combustion engine fixed, an ECU (PM-ECU) that performs power distribution regardless of the required output (Ptotal) required for the vehicle ) Controls Pe to a constant value (this control is hereinafter referred to as “Pe constant control”). During constant Pe control, the shortage of the driving force of the vehicle is compensated by the assist driving force of the motor. If the required output (Ptotal) required for the vehicle during Pe constant control increases beyond the assistable range of the motor, it is necessary to interrupt Pe constant control and cause the internal combustion engine to output engine torque.

  However, in a hybrid vehicle, Pe is set low because the internal combustion engine is mainly used to raise the temperature of the catalyst during catalyst warm-up. For this reason, when the required output (Ptotal) required for the vehicle suddenly increases based on the accelerator operation of the user or the like, there is a concern that a response delay may occur due to poor response of the internal combustion engine.

  On the other hand, an internal combustion engine having a variable valve gear that can change the operating characteristics of an intake valve is known. Furthermore, as such a variable valve apparatus, a variable valve apparatus that can change at least one of the lift amount and the operating angle of an intake valve is known. An internal combustion engine having such a variable valve operating device may also be used for a hybrid vehicle.

  In the above Japanese Patent Laid-Open No. 2012-40915, the variable valve operating device has not been studied, and there is still room for improvement in terms of improving the responsiveness in the internal combustion engine having the variable valve operating device.

  An object of the present invention is to provide a hybrid vehicle equipped with an internal combustion engine that has a variable valve system and that has a reduced response delay even during catalyst warm-up.

  In summary, the present invention is an internal combustion engine having an electric motor that generates a vehicle driving force and a variable valve operating device for changing the operating characteristics of an intake valve defined including a lift amount and a working angle. An engine, an exhaust purification device that purifies exhaust gas from the internal combustion engine using a catalyst, and a control device that executes catalyst warm-up control for warming up the catalyst of the exhaust purification device. The catalyst warm-up control includes the first control for operating the internal combustion engine at the first operation point, and the internal combustion engine that is more effective than the first operation point regardless of the driving force required for traveling after the execution of the first control. The second control for operating the internal combustion engine at the second operating point where the output of the engine is large, and after the execution of the second control, the internal combustion engine is operated based on the driving force required for traveling. And a third control for controlling the variable valve operating apparatus based on the rotational speed and the torque. During execution of the second control, the control device controls the variable valve device so that the maximum value of at least one of the lift amount and the operating angle of the intake valve decreases as the required output increases, Controls the motor so that the motor shares.

  Preferably, during execution of the first control, the control device operates the internal combustion engine with the ignition timing of the internal combustion engine retarded relative to during execution of the second control. Is configured to be changeable into a first characteristic and a second characteristic in which at least one of the lift amount of the intake valve and the operating angle of the intake valve is larger than when the operating characteristic is the first characteristic. Further, during the execution of the first control, the variable valve apparatus is controlled so that the operation characteristic becomes the first characteristic, and during the execution of the second control, the operation characteristic is switched to the second characteristic. In this way, the variable valve gear is controlled.

  During the execution of the second control, the electric motor is controlled so that the electric motor shares the change in the required output while suppressing the output of the internal combustion engine to a predetermined amount smaller than the required output. However, when the required output increases, the electric motor may not be shared. In such a case, it is necessary to control the vehicle so that the second control is interrupted and the output of the internal combustion engine is increased to output the required output. Therefore, it is desirable to increase the responsiveness of the internal combustion engine in advance when there is a high possibility that the required output increases and the motor cannot be shared. Even during execution of the second control, the response of the internal combustion engine is controlled by controlling the variable valve mechanism so that the maximum value of at least one of the lift amount and the operating angle of the intake valve decreases as the required output increases. Since the performance increases, the response delay of the vehicle is reduced when the required output is suddenly increased.

  Preferably, the required output during execution of the second control includes an output required for the vehicle when the control of the internal combustion engine is switched from the second control to the third control.

  By defining in this way, it becomes clear that the control is also performed when the control of the internal combustion engine is switched from the second control to the third control.

  Preferably, the control device calculates the required output based on the vehicle speed, the accelerator opening, and the required driving force required for the vehicle.

  Preferably, the variable valve operating apparatus is configured to be able to change the maximum value of at least one of the lift amount and the operating angle of the intake valve into three stages of first to third values. The first to third values are set such that the second value is larger than the first value and the third value is larger than the second value. During execution of the second control, when the required driving force required for the vehicle is larger than a predetermined value, the control device sets the maximum value of at least one of the lift amount and the operating angle of the intake valve to the first value. If the required driving force is smaller than a predetermined value, the maximum value of at least one of the lift amount and the operating angle of the intake valve is set to the third value.

  Preferably, the variable valve operating apparatus is configured to be able to change the maximum value of at least one of the lift amount and the operating angle of the intake valve into two stages of a first value and a second value. The first value and the second value are set to be larger than the first value. During execution of the second control, when the required driving force required for the vehicle is larger than a predetermined value, the control device sets the maximum value of at least one of the lift amount and the operating angle of the intake valve to the first value. If the required driving force is smaller than a predetermined value, the maximum value of at least one of the lift amount and the operating angle of the intake valve is set to the second value.

  According to the present invention, in a hybrid vehicle, response delay can be reduced even during catalyst warm-up.

1 is a block diagram showing an overall configuration of a hybrid vehicle according to Embodiment 1 of the present invention. It is a block diagram of the engine 100 shown in FIG. It is a figure which shows the relationship between the valve displacement amount implement | achieved in the VVL apparatus 400, and a crank angle. 2 is a front view of a VVL device 400. FIG. FIG. 5 is a perspective view partially showing the VVL device 400 shown in FIG. 4. It is a figure which shows the relationship between the valve displacement amount and crank angle which are implement | achieved in the VVL apparatus 400 which can change the operating characteristic of the intake valve 118 in three steps. It is a figure explaining the operation | movement at the time of piston raising when the lift amount and operating angle of the intake valve 118 are large. It is a figure explaining the operation | movement at the time of piston raising when the lift amount and action angle of the intake valve 118 are small. It is a figure explaining the operation | movement at the time of piston downward movement when the lift amount and operating angle of the intake valve 118 are small. It is a figure which shows the operating line of the engine 100 which has the VVL apparatus 400 which has the operating characteristic which can be changed in three steps shown in FIG. It is a wave form diagram for demonstrating the control state of an engine from an engine start until a VVL apparatus is normally controlled. 7 is a flowchart for illustrating control for determining a lift amount and an operating angle of a VVL device 400 in second warm-up control during catalyst warm-up. It is a wave form diagram for demonstrating the control state of an engine from the engine starting in a modification until a VVL apparatus is normally controlled.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a plurality of embodiments will be described. However, it is planned from the beginning of the application to appropriately combine the configurations described in the embodiments. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  The present embodiment is characterized by the control of the variable valve lift mechanism of the engine in the period T4 in FIG. 11. As a precondition, the overall configuration of the hybrid vehicle, the configuration of the engine, and the variable valve lift mechanism (VVL device) of the engine are used. First, an explanation will be given.

(Overall configuration of hybrid vehicle)
FIG. 1 is a block diagram showing an overall configuration of a hybrid vehicle according to Embodiment 1 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 a control device 200.

  Hybrid vehicle 1 can travel with a driving force output from at least one of engine 100 and motor generator MG2. Power split device 4 is configured to be able to split the driving force generated by engine 100 into a driving force for driving drive wheels 6 and a driving force for driving motor generator MG1. The power split device 4 includes, for example, a planetary gear mechanism.

  Engine 100 generates the driving force of the vehicle. Engine 100 generates a driving force for driving motor generator MG1 operable as a generator. Engine 100 can be started by being cranked by motor generator MG1. The engine 100 has a variable valve operating device for changing the operation characteristic of the intake valve. The control device 200 controls the variable valve operating device according to the situation of the vehicle. The configurations of the engine 100 and the variable valve operating apparatus will be described in detail later with reference to FIGS.

  Motor generators MG1 and MG2 are AC rotating electric machines, for example, three-phase AC synchronous motor generators. Motor generator MG <b> 1 can generate electric power using the driving force of engine 100. For example, when SOC of power storage device B reaches a predetermined lower limit, engine 100 is started and electric power is generated by motor generator MG1. The electric power generated by motor generator MG1 is voltage-converted by PCU 20, and is temporarily stored in power storage device B or directly supplied to motor generator MG2.

  Motor generator MG2 generates a driving force using at least one of the electric power stored in power storage device B and the electric power generated by motor generator MG1. The driving force of motor generator MG2 is transmitted to driving wheels 6 via reduction gear 5. In FIG. 1, the drive wheels 6 are shown as front wheels, but the rear wheels may be driven by the motor generator MG2 instead of the front wheels or together with the front wheels.

  During braking of the vehicle, the motor generator MG2 is driven by the drive wheels 6 via the speed reducer 5, and the motor generator MG2 operates as a generator. Thereby, motor generator MG2 operates as a regenerative brake that converts braking energy into electric power. The electric power generated by motor generator MG2 is stored in power storage device B.

  PCU 20 is a drive device for driving motor generators MG1 and MG2. PCU 20 includes an inverter for driving motor generators MG1 and MG2, and may further include a converter for voltage conversion between the inverter and power storage device B.

  The power storage device B is a rechargeable DC power source, and includes, for example, a secondary battery such as a nickel metal hydride battery or a lithium ion battery. The voltage of power storage device B is, for example, about 200V. Power storage device B stores the electric power generated by motor generators MG1, MG2. A large-capacity capacitor can also be used as power storage device B, and power storage device B temporarily stores the power generated by motor generators MG1 and MG2, and stores the stored power to motor generator MG2 and voltage converter 30. Any power buffer that can be supplied may be used. In addition, power storage device B detects voltage VB and current IB of power storage device B and outputs the detected values to control device 200.

  The control device 200 is configured to include an ECU (Electronic Control Unit) including a CPU (Central Processing Unit), a storage device, an input / output buffer, and the like (all not shown). The control device 200 receives signals (accelerator opening degree ACC, vehicle speed VSS, etc.) from various sensors, transmits control signals to each device, and controls each device in the hybrid vehicle 1. As an example, the control device 200 executes traveling control of the hybrid vehicle 1, charging control of the power storage device B, control of the engine 100 including a variable valve operating device, and the like.

(Configuration of engine 100)
FIG. 2 is a configuration diagram 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 driven by a throttle motor 312.

  The sucked air is mixed with fuel in the cylinder 106 (combustion chamber). Fuel is injected into the cylinder 106 from an injector 108. In this embodiment, the engine 100 is described as a port injection type in which the injection hole of the injector 108 is provided in the intake port. However, in addition to the port injection injector 108, fuel is directly supplied into the cylinder 106. You may provide the injector for direct injection to inject. 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, 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. Further, a part of the exhaust gas is returned to the intake port as EGR (Exhaust Gas Recirculation) gas through a reflux path (not shown).

  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, and 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 be controllable. Further, a VVT (Variable Valve Timing) device that controls the opening / closing timing of the valve may be combined with the VVL device 400.

  The controller 200 controls the throttle opening θth, the ignition timing, the fuel injection timing, the fuel injection amount, the fuel injection amount, the engine 100 so that the engine 100 is operated at a desired operating point in accordance with the vehicle running condition and the exhaust gas purification apparatus warm-up condition. Controls the operating state of the intake valve (open / close timing, lift amount, working angle, etc.). The operating point is an operating point of the engine 100 at which the power, torque, and rotation speed of the engine 100 are determined, and the operating point of the engine 100 is determined so that the engine 100 outputs desired power and torque. . In the first embodiment, the operating point is set so that the power of engine 100 becomes a desired operating power. Signals are input to the control device 200 from the cam angle sensor 300, the crank angle sensor 302, the knock sensor 304, and the 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.

  Control device 200 controls engine 100 based on signals from these sensors.

  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 (FIG. 2) opens and closes in the exhaust stroke, and intake valve 118 (FIG. 2) opens and closes in the intake stroke. A waveform EX is a valve displacement amount of the exhaust valve 120, and waveforms IN1 and IN2 are valve displacement amounts of the intake valve 118. The valve displacement is the displacement of the valve from the closed state. In the following, the lift amount is a valve displacement amount when the opening degree of the intake valve 118 reaches a peak, and 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. Note that the VVL device 400 of the present embodiment is configured such that the lift amount and the operating angle can be changed in three stages later as shown in FIG.

  FIG. 4 is a front view of the VVL device 400. The configuration illustrated in FIG. 4 is an example, and the VVL device 400 is not limited to such a configuration. 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 shown in FIG. In FIG. 5, a part thereof is shown to be broken so that the internal structure can be grasped. 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.

  Note that the VVL device 400 is not limited to this type. For example, a VVL device that electrically drives a valve, a VVL device that drives a valve using hydraulic pressure, or the like 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 diagram showing the relationship between the valve displacement amount and the crank angle realized in the VVL device 400 that can change the operation characteristic of the intake valve 118 in three stages. The VVL device 400 can change the operating 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. 7 is a view for explaining the operation when the piston is lifted when the lift amount and the operating angle of the intake valve 118 are large. FIG. 8 is a view for explaining the operation when the piston is lifted when the lift amount and the operating angle of the intake valve 118 are small. Referring to FIGS. 7 and 8, when the lift amount and operating angle of intake valve 118 are large, the timing for closing intake valve 118 when the piston 114 is raised is delayed, so engine 100 operates in the Atkinson cycle. Is done. That is, a part of the air sucked into the cylinder 106 in the intake stroke is returned to the outside of the cylinder 106, and the compression reaction force that is a force for compressing the air in the compression stroke is reduced. Thereby, the vibration at the time of engine starting can be reduced. Since the compression ratio decreases, the ignitability deteriorates and the output responsiveness of engine 100 decreases.

  On the other hand, when the lift amount and the operating angle of the intake valve 118 are small, the timing for closing the intake valve 118 when the piston 114 is raised is earlier, so the compression ratio is increased. This improves the ignitability at low temperatures and improves the engine output response. Since the compression reaction force increases, the vibration at the time of starting the engine can increase.

  FIG. 9 is a diagram for explaining the operation when the piston descends when the lift amount and the operating angle of the intake valve 118 are small. Referring to FIG. 9, when the lift amount and operating angle of intake valve 118 are small, the timing for opening intake valve 118 when piston 114 is lowered is delayed. As a result, the intake air is sucked from the intake port in a state where a negative pressure is generated in the cylinder 106, so that mixing of fuel in the cylinder 106 is promoted and combustion can be improved.

  FIG. 10 is a diagram showing an operating line of engine 100 having VVL device 400 having operating characteristics changeable in three stages shown in FIG. In the hybrid vehicle of the present embodiment, the normal control shown in the operation characteristics according to FIG. 10 is performed after the catalyst warm-up is completed.

  Referring to FIG. 10, the horizontal axis represents the engine speed, and the vertical axis represents the engine torque. A line indicated by an alternate long and short dash line indicates torque characteristics corresponding to the first to third characteristics (IN1a to IN3a). A circle indicated by a solid line represents an equal fuel consumption line, and the closer to the center of the circle, the better the fuel efficiency. It is assumed that engine 100 is basically operated on an engine operating line represented by a solid line.

  In the operation line shown in FIG. 10, the lift amount and the operating angle are selected to be optimal in the low rotation range, the middle rotation range, and the high rotation range.

  That is, in FIG. 10, it is important to suppress the vibration at the time of starting the engine in the low rotation range indicated by the region R1. In this low speed range, the introduction of EGR gas is stopped, and fuel efficiency is improved by the Atkinson cycle. Therefore, in the region R1, 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, in the region R2, 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, in the region R3, 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.

  Although FIG. 10 shows the characteristics of the normal control VVL device 400, when the catalyst is warmed up, the VVL device 400 is controlled differently from FIG. When the catalyst is warmed up, when the engine 100 is operated at a high load in a low rotation range, or when the engine 100 is started at an extremely low temperature, the operation of the intake valve 118 is performed so that the lift amount and the operating angle become small. The first characteristic (IN1a) is selected as the characteristic. Thus, the lift amount and the operating angle are determined according to the operating state of engine 100.

  FIG. 11 is a waveform diagram for explaining the control state of the engine from when the engine is started until the VVL device is normally controlled. In the horizontal axis of FIG. 11, time is shown, and in order from the top, engine speed Ne, engine power Pe, ignition timing aop, catalyst purification rate (for example, end face 10 mm), catalyst purification rate (center), combustion temperature, A waveform showing the state of intake valve control is shown.

  Since the period T1 is immediately after the engine is started and the temperatures of the engine and the catalyst are low, the first warm-up control is executed. In the first warm-up control, the engine power Pe is set to almost zero, and the driving torque of the vehicle is mainly output from the traveling motor. In this period T1, the ignition timing aop of the engine 100 is controlled to the retard side, and the engine 100 is operated at a first operating point where the engine power Pe is the first operating power P1. As an example, the first operating power P1 is set to a low power of about 0 to 3 kW, and at this first operating point, the rotation speed of the engine 100 is set to the idling rotation speed, and the engine torque is equal to the engine power Pe. Is set to be the first operating power P1. During this time, priority is given to catalyst warm-up for exhaust gas purification. For this reason, the engine is controlled so that the ignition timing aop of the engine is retarded and the temperature of the combustion gas becomes high. The intake valve control is controlled by the VVL device 400 with the characteristic (IN1a) shown in FIG. As a result, the opening of the intake valve is delayed, and as described with reference to FIG. 9, the intake valve is opened after the negative pressure is generated in the cylinder. The gas approaches a clean state.

  When the period T1 elapses, the end face (for example, about 10 mm) of the catalyst 112S in FIG. 2 near the engine rises to an appropriate temperature, and the purification rate reaches 100%. However, in this state, since the temperature has not been sufficiently raised up to the central portion of the catalyst 112S, the catalyst 112S has not reached its full capacity. Therefore, after the period T1 has elapsed, the second warm-up control is executed before shifting to the normal control. After this period T1 has elapsed, the engine is operated at the second operating point. At the second operating point, various parameters of the engine are controlled so that the engine output is larger than that of the first operating point. That is, control device 200 controls engine 100 to operate engine 100 at a second operation point where engine power Pe is set to second operation power P2 that is higher than first operation power P1. The second operating power is determined within the range of the exhaust purification capacity of the S / C catalyst 112S without responding to the traveling power, and may be a constant value or the exhaust purification capacity of the S / C catalyst 112S. You may raise with a raise (temperature rise of S / C catalyst 112S). As an example, at this second operating point, the engine speed is set to the idling engine speed, and after the engine torque is switched from the first warm-up control to the second warm-up control, the engine power Pe is The operating power P1 is set so as to gradually increase from the first operating power P1 to the second operating power P2.

  That is, at the time of executing the second warm-up control, control device 200 returns ignition timing aop of engine 100 that has been controlled to the retard side to the normal state and a second operating power that is greater than the first operating power. Then, engine 100 is operated. The second operating power does not respond to the traveling power and is set to a predetermined value that does not exceed the exhaust gas purification capacity of the catalyst 112S. This predetermined value may be a constant value, or may be increased stepwise as the exhaust purification capacity of the catalyst 112S increases (the temperature of the catalyst 112S increases). During this time, traveling power is output from motor generator MG2.

  In the present embodiment, an example of executing Pe constant control for controlling engine power Pe constant as the second warm-up control is shown. The catalyst temperature is determined by the heat capacity of the catalyst and the amount of heat given to the catalyst. Since the amount of heat is related to the integrated air amount, it is estimated by mapping the relationship between the integrated air amount and the catalyst temperature in advance. Is possible.

  The second warm-up control is to improve fuel efficiency while taking measures to prevent exhaust gas deterioration. The second warm-up control is executed in the periods T2, T3, T4.

  In the period T2, when the temperature of the end face of the catalyst 112S rises to an appropriate temperature and the catalyst can exhibit a part of the purification capability, the retardation of the ignition timing aop of the engine ends. Then, the engine is controlled so that the ignition timing aop of the engine is advanced and the fuel consumption is improved. The engine power Pe is gradually increased from zero and fixed at a constant value so as to correspond to the amount of gas that can be purified by the catalyst. During this time, the engine speed Ne is also controlled to a constant value. Since the engine speed Ne and the engine power Pe are fixed to a constant value, the warming up of the catalyst is continued in a state where the operation of the engine is stable.

  In the period T2, the intake valve control is controlled by the VVL device 400 with the characteristic (IN2a) shown in FIG. During the period T2, while the catalyst purification rate has increased, the lift amount and operating angle of the intake valve are set to intermediate characteristics (IN2a) while the engine ignition timing aop at which combustion becomes unstable is being returned to the advance side. Is. This aims at an intermediate effect between the improvement in combustion in the state in which the compression ratio is increased by the early closing of the intake valve (FIGS. 8 and 9) and the improvement in fuel efficiency by the Atkinson cycle (FIG. 7) by the late closing of the intake valve.

  When the combustion temperature is equal to or higher than a certain temperature and the engine operation is stabilized, the control shifts to the period T3 (when the engine is operated with the combustion temperature equal to or lower than the certain temperature, the combustion becomes slow and the fuel consumption is poor). In the period T3, the VVL device 400 is basically controlled with the characteristic (IN3a) shown in FIG. By setting the VVL device 400 to the characteristic (IN3a), it is possible to obtain the fuel efficiency improvement effect by the Atkinson cycle (FIG. 7) by the late closing of the intake valve.

  When the second warm-up control ends, normal control is executed in the period T5. In the normal control, the lift amount and the operating angle of the VVL device 400 are controlled based on, for example, the characteristics shown in FIG. 10 based on the engine speed Ne and the engine load. When the second warm-up control is shifted to the normal control, the required power for the engine is changed from a constant value to a value determined based on the required driving force.

  Here, the period T4 is a period immediately before the period T5 in which the normal control is performed. Therefore, it is preferable to increase the responsiveness in preparation for a case where a high engine power Pe is required in the normal control. In order to enhance the responsiveness, it is preferable to operate the VVL device 400 with the characteristic IN1a (the lift amount and the working angle are small). However, in the period T4, the characteristic IN1a is more disadvantageous in terms of fuel consumption than the characteristic IN3a (lift amount and operating angle is large).

  Therefore, in the present embodiment, the characteristics of the VVL device 400 in the period T4 are changed according to the magnitude of the driving force request based on the accelerator pedal operation from the driver. When the driving force request is smaller than the threshold value, the fuel consumption is prioritized, and the VVL device 400 is controlled with the characteristic IN3a (lift amount and working angle is large) as shown by the solid line in the period T4 in FIG. On the other hand, when the driving force requirement is larger than the threshold value, priority is given to responsiveness, and the VVL device 400 is controlled with the characteristic IN1a (the lift amount and the working angle are small) as shown by the solid line in the period T4 in FIG. .

  Even when the driving force requirement is larger than the threshold value, the second warm-up control is interrupted when it exceeds a value that can be supplemented by the motor in the second warm-up control. Control will be transferred.

  FIG. 12 is a flowchart for illustrating control for determining the lift amount and operating angle of the VVL device 400 in the second warm-up control during catalyst warm-up. Although the second warm-up control has been described with reference to FIG. 11, the second warm-up control is performed during a period during which the first warm-up control shifts to the normal control. Then, the process of the flowchart of FIG. 12 is executed in the latter half of the second warm-up control (period T13).

  Referring to FIG. 12, when the process is started, it is determined in step S1 whether the second warm-up control is possible. For example, if the power required to output the required driving force determined based on the user's accelerator operation is greater than P1 (kW), the driving force is supplemented by the battery and the motor when the second warm-up control is performed. Cannot be realized.

  Therefore, when the required driving force is greater than the predetermined value, it is determined that the second warm-up control is impossible, and the process proceeds from step S1 to step S6. In addition, the process proceeds from step S1 to step S6 also when a condition for sufficiently increasing the catalyst temperature and shifting to normal control is satisfied. In step S6, the control of the lift amount and the operating angle of the intake valve is set to normal control as described with reference to FIG. 10, for example, and the processing of this flowchart ends in step S7.

  On the other hand, if the condition for performing the second warm-up control is satisfied in step S1, the process proceeds to step S2. In step S2, it is determined whether or not the catalyst temperature is higher than a threshold value (° C.). This threshold value is a temperature that is set slightly lower than the catalyst temperature at which the second warm-up control is completed, and indicates that the second warm-up control is expected to end soon. If it is determined in step S2 that the catalyst temperature is higher than the threshold value, the process proceeds to step S4. If it is determined that the catalyst temperature is equal to or lower than the threshold value, the process proceeds to step S3.

  In step S3, it is determined whether or not the driving force request is greater than a threshold value. This threshold value is set within a range in which the second warm-up control can be continued. For example, when the required driving force is smaller than the threshold value, there is a low possibility that a large required driving force that must exit the second warm-up control during the second warm-up control is generated. On the other hand, when the required driving force is larger than the threshold value, it is unlikely that a large required driving force that must exit the second warm-up control during the second warm-up control is generated.

  Therefore, if the driving force request is greater than the threshold value in step S3, the process proceeds to step S4, and if the driving force request is equal to or less than the threshold value, the process proceeds to step S5.

  In step S4, in order to improve responsiveness, the VVL device 400 is controlled so that the lift amount of the intake valve is reduced and the operating angle is set to a small operating angle (IN1a). On the other hand, in step S5, the VVL device 400 is controlled so that the lift amount of the intake valve is increased in order to improve fuel efficiency and the operating angle is set to the large operating angle (IN3a). In step S4 or S5, after the lift amount and the operating angle are set, the processes after step S1 are executed again.

  In step S3, the lift amount and the working angle are determined based on the driving force request, but the lift amount and the working angle may be determined based on the vehicle speed or power instead of or in addition to the driving force request. good.

  As described above, in the present embodiment, during the second warm-up control in the hybrid vehicle or the plug-in hybrid vehicle equipped with the engine in which the lift amount and the operating angle of the intake valve are configured to be variable in three stages, The lift amount and operating angle of the intake valve are variably set according to the vehicle driving force requirements.

  Specifically, when the driving force requirement is small, the VVL device is set to a large lift amount and a large operating angle, and the second warm-up control is performed with an emphasis on fuel consumption. On the other hand, when the driving force request is large or immediately before the end of the second warm-up control, the VVL device has a small lift amount and a small working angle with good torque response so that it can immediately respond to the increase in the engine driving force request. The second warm-up control is performed by switching to. By doing so, it is possible to cope with a sudden increase in driving force demand while improving fuel efficiency.

[Modification]
In the above embodiment, the control of the engine in which the characteristics of the VVL device can be changed in three stages has been described, but the control of the lift amount and the operating angle during the second warm-up control is not limited to this. . For example, the present invention can be applied to an engine that can be changed to two stages, more than three stages, or whose characteristics are continuously changed. In the following, application to a VVL device configured to change the characteristics in two steps will be described as a modification.

  The VVL device according to the modification is different from FIG. 6 in that the characteristics of the intake valve are switched to two stages IN1a and IN3a, and the characteristic IN2a is not used, but the vehicle configuration, the engine configuration, and the VVL device configuration Since is the same as the configuration described in FIGS. 1 to 5, description thereof will not be repeated.

  FIG. 13 is a waveform diagram for explaining the control state of the engine from the engine start to the normal control of the VVL device in the modified example. The horizontal axis of FIG. 13 indicates time, and in order from the top, engine speed Ne, engine power Pe, ignition timing aop, catalyst purification rate (end face 10 mm), catalyst purification rate (center), combustion temperature, intake valve A waveform indicating the state of control is shown.

  The period T11 is immediately after the engine is started and the temperatures of the engine and the catalyst are low, so the first warm-up control is executed. The engine ignition timing aop is retarded. The intake valve control is controlled by the VVL device 400 with the characteristic (IN1a) shown in FIG.

  When the period T11 elapses, the end surface (about 10 mm) of the catalyst 112S in FIG. 2 on the side close to the engine rises to an appropriate temperature, and the purification rate reaches 100%. However, in this state, since the temperature has not been sufficiently raised up to the central portion of the catalyst 112S, the catalyst 112S has not reached its full capacity. Therefore, after the period T11 has elapsed, the second warm-up control is performed in which the engine power Pe is controlled to be constant before shifting to the normal control.

  The second warm-up control is to improve fuel efficiency while taking measures to prevent exhaust gas deterioration. The second warm-up control is executed in the periods T12, T13, T14.

  In the period T12, when the temperature of the end face of the catalyst 112S rises to an appropriate temperature and the catalyst can exhibit a part of the purification capability, the retard of the ignition timing aop of the engine ends. Then, the engine is controlled so that the ignition timing aop of the engine is advanced and the fuel consumption is improved. The engine power Pe is gradually increased from zero and fixed at a constant value so as to correspond to the amount of gas that can be purified by the catalyst. During this time, the engine speed Ne is also controlled to a constant value. Since the engine speed Ne and the engine power Pe are fixed to a constant value, the warming up of the catalyst is continued in a state where the operation of the engine is stable.

  In the period T12, the intake valve control is controlled by the VVL device 400 with the characteristic (IN1a) shown in FIG. During the period T12, while the catalyst purification rate has increased, while the engine ignition timing aop at which combustion becomes unstable is being returned to the advance side, the lift amount and working angle of the intake valve are reduced to the small lift amount and small working angle. Characteristic (IN1a). Thus, priority is given to the purification of exhaust gas by the combustion improvement (FIGS. 8 and 9) in the state where the compression ratio is increased by the early closing of the intake valve.

  When the combustion temperature is equal to or higher than a certain temperature and the engine operation is stabilized, the control proceeds to the period T13 (when the engine is operated with the combustion temperature equal to or lower than the certain temperature, the combustion becomes slow and the fuel consumption is poor). In the period T13, the VVL device 400 is basically controlled with the characteristic (IN3a) shown in FIG. By setting the VVL device 400 to the characteristic (IN3a), it is possible to obtain the fuel efficiency improvement effect by the Atkinson cycle (FIG. 7) by the late closing of the intake valve.

  When the second warm-up control ends, normal control is executed in the period T15. In the normal control, the lift amount and the operating angle of the VVL device 400 are controlled based on, for example, the characteristics shown in FIG. 10 based on the engine speed Ne and the engine load. When the second warm-up control is shifted to the normal control, the required power for the engine is changed from a constant value to a value determined based on the required driving force.

  Here, the period T14 is a period immediately before the period T15 in which the normal control is performed. Therefore, it is preferable to increase the responsiveness in preparation for a case where a high engine power Pe is required in the normal control. In order to enhance the responsiveness, it is preferable to operate the VVL device 400 with the characteristic IN1a (the lift amount and the working angle are small). However, in the period T14, the characteristic IN1a is more disadvantageous in terms of fuel consumption than the characteristic IN3a (lift amount and operating angle is large).

  Therefore, in the present embodiment, the characteristics of the VVL device 400 in the period T14 are changed according to the magnitude of the driving force request based on the accelerator pedal operation from the driver. When the driving force request is smaller than the threshold value, the fuel efficiency is prioritized, and the VVL device 400 is controlled with the characteristic IN3a (lift amount and working angle is large) as shown by the solid line in the period T14 in FIG. On the other hand, when the driving force request is larger than the threshold value, priority is given to responsiveness, and the VVL device 400 is controlled with the characteristic IN1a (the lift amount and the working angle are small) as shown by the solid line in the period T14 in FIG. .

  Even when the driving force requirement is larger than the threshold value, the second warm-up control is interrupted when it exceeds a value that can be supplemented by the motor in the second warm-up control. Control will be transferred.

  The determination of the lift amount and the operating angle in the period T14 is performed by the same processing as in FIG. 12, and therefore description thereof will not be repeated here.

  According to the modified example, even when the characteristics of the VVL device 400 are configured to be variable in two stages, the responsiveness of the vehicle can be improved.

  In each of the above-described embodiments, 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 relates to either the lift amount of the intake valve 118 or the operating angle of the intake valve 118. The present invention can also be applied to a hybrid vehicle equipped with an engine having a variable valve operating device capable of changing the above. Even in the variable valve gear that can change either the lift amount or the working angle of the intake valve 118, the same effect as when both the lift amount and the working angle of the intake valve 118 can be changed can be obtained. Note that a variable valve gear that can change either the lift amount or the operating angle of the intake valve 118 can be realized using various known techniques.

  Further, in each of the above embodiments, the control device 200 controls the power of the engine 100 (controls to the first or second operating power) with respect to the output of the engine 100. May be controlled (torque demand control). That is, in the first warm-up control, the control device 200 operates the engine 100 so that the engine 100 outputs the first torque, and in the second warm-up control, the engine 100 causes the second torque (second The engine 100 may be operated so as to output (torque> first torque). In this case, in the first warm-up control, the first operating point is set so that the torque of the engine 100 becomes the first torque, and in the second warm-up control, the torque of the engine 100 becomes the second torque. The second operation point is set at.

  Finally, the present embodiment and modifications will be summarized with reference to the drawings again. Referring to FIGS. 1 to 6, hybrid vehicle 1 changes an operating characteristic of an electric motor (motor generator MG <b> 2) that generates vehicle driving force, and intake valve 118 that is defined including a lift amount and a working angle. An internal combustion engine (engine 100) having a variable valve system (VVL device 400), an exhaust purification device that purifies exhaust gas from the internal combustion engine using a catalyst, and catalyst warm-up control that warms up the catalyst of the exhaust purification device And a control device 200 to be executed. The catalyst warm-up control is required for running after the first control (first warm-up control) for operating the internal combustion engine at the first operating point in order to warm up the catalyst rapidly and the first control. A second control (second warm-up control) for operating the internal combustion engine at a second operation point where the output of the internal combustion engine is larger than the first operation point, regardless of the driving force applied; After the execution, the internal combustion engine is operated based on the driving force required for traveling, and the third control (normal control) for controlling the variable valve operating apparatus based on the rotation speed and torque of the internal combustion engine is included. During the execution of the second control, the control device 200 controls the variable valve device so that the maximum value of at least one of the lift amount and the operating angle of the intake valve 118 decreases as the required output increases. The motor is controlled so that the change is shared by the motor.

  Preferably, control device 200 operates the internal combustion engine during the execution of the first control with the ignition timing of the internal combustion engine retarded relative to the execution of the second control. The variable valve operating apparatus has an operating characteristic in which at least one of the first characteristic (IN1a) and the lift amount of the intake valve 118 and the operating angle of the intake valve 118 is larger than when the operating characteristic is the first characteristic. 2 characteristics (IN2a or IN3a). The control device 200 further controls the variable valve gear so that the operating characteristic becomes the first characteristic during execution of the first control, and sets the operating characteristic to the second characteristic during execution of the second control. The variable valve gear is controlled to switch to the characteristic.

  During the execution of the second control (second warm-up control), the motor generator MG2 is controlled so that the motor generator MG2 shares the change in the required output while suppressing the output of the engine 100. However, when the required output increases, the motor generator MG2 may not be shared. In such a case, it is necessary to interrupt the second control (second warm-up control) and increase the output of the engine 100 to control the vehicle so that the required output is output. Therefore, when it is highly likely that the required output increases and motor generator MG2 cannot be shared, it is desirable to increase the response of engine 100 in advance. Even during execution of the second control (second warm-up control), the VVL device 400 is controlled so that the maximum value of at least one of the lift amount and the operating angle of the intake valve 118 becomes smaller as the required output increases. As a result, the responsiveness of the engine 100 is enhanced, so that the response delay of the vehicle is reduced when the required output is rapidly increased.

  In FIGS. 11 to 13, the characteristics of the periods T4 and T14 are expressed in two stages of IN1a and IN3a so that the lift amount and the operating angle are smaller when the required driving force (or required output) is large than when it is small. However, these are only examples, and the higher the required output, the higher the intake valve lift amount and the maximum operating angle may be reduced in multiple steps or continuously.

  Preferably, the requested output during execution of the second control is an output required for the vehicle when switching the control of engine 100 from the second control (second warm-up control) to the third control (normal control). including.

  Preferably, control device 200 calculates the required output based on the vehicle speed, the accelerator opening, and the required driving force required for the vehicle. The driving force required for the vehicle means that the case where the control device of the vehicle determines the required driving force regardless of the accelerator pedal during automatic traveling or the like is included.

  Preferably, as shown in FIG. 11, VVL device 400 changes the maximum value of at least one of the lift amount and operating angle of intake valve 118 to three stages of first to third values (corresponding to IN1a to IN3a). Configured to be possible. The first to third values are set such that the second value is larger than the first value and the third value is larger than the second value. During execution of the second control, the control device 200 determines the maximum value of at least one of the lift amount and the operating angle of the intake valve 118 when the required driving force required for the vehicle is greater than a predetermined value. When the required driving force is smaller than a predetermined value, the maximum value of at least one of the lift amount and the operating angle of the intake valve 118 is set to the third value.

  Preferably, as shown in the modification of FIG. 13, the VVL device 400 sets the maximum value of at least one of the lift amount and the operating angle of the intake valve 118 to the first and second values (corresponding to IN1a and IN3a). It is configured to be changeable in stages. The first value and the second value are set to be larger than the first value. During execution of the second control, the control device 200 determines the maximum value of at least one of the lift amount and the operating angle of the intake valve 118 when the required driving force required for the vehicle is greater than a predetermined value. When the required driving force is smaller than a predetermined value, the maximum value of the lift amount and the operating angle of the intake valve 118 is set to the second value (corresponding to IN3a). .

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  DESCRIPTION OF SYMBOLS 1 Hybrid vehicle, 4 Power split device, 5 Reducer, 6 Drive wheel, 30 Voltage converter, 100 Engine, 102 Air cleaner, 104 Throttle valve, 106 Cylinder, 108 Injector, 110 Spark plug, 112 Three-way catalyst, 112S Catalyst, 114 piston, 116 crankshaft, 118 intake valve, 120 exhaust valve, 122,124 cam, 128 rocker arm, 130 camshaft, 200 control device, 300 cam angle sensor, 302 crank angle sensor, 304 knock sensor, 306 throttle opening sensor 312 Throttle motor, 400 VVL device, B power storage device, MG1, MG2 motor generator.

Claims (6)

An electric motor for generating vehicle driving force;
An internal combustion engine having a variable valve system for changing the operating characteristics of an intake valve defined including a lift amount and a working angle;
An exhaust emission control device for purifying exhaust gas of the internal combustion engine using a catalyst;
A control device for performing catalyst warm-up control for warming up the catalyst of the exhaust purification device,
The catalyst warm-up control is
A first control for operating the internal combustion engine at a first operating point;
After the execution of the first control, a second operating point that operates the internal combustion engine at a second operating point where the output of the internal combustion engine is larger than the first operating point, regardless of the driving force required for traveling. Control,
After the execution of the second control, the third internal combustion engine is operated based on the driving force required for traveling, and the variable valve apparatus is controlled based on the rotational speed and torque of the internal combustion engine. Control and
During execution of the second control, the control device controls the variable valve operating device so that the maximum value of at least one of the lift amount and the operating angle of the intake valve decreases as the required output increases. A hybrid vehicle that controls the electric motor so that a change in output is shared by the electric motor. The control device operates the internal combustion engine during the execution of the first control with the ignition timing of the internal combustion engine retarded relative to the execution of the second control,
In the variable valve operating apparatus, the operating characteristic is greater in at least one of the first characteristic and the lift amount of the intake valve and the operating angle of the intake valve than when the operating characteristic is the first characteristic. It is configured to be changeable to the second characteristic,
The control device further includes:
During the execution of the first control, the variable valve apparatus is controlled so that the operating characteristic becomes the first characteristic,
2. The hybrid vehicle according to claim 1, wherein during the execution of the second control, the variable valve apparatus is controlled to switch the operation characteristic to the second characteristic.   2. The hybrid according to claim 1, wherein the required output during execution of the second control includes an output required for a vehicle when switching control of the internal combustion engine from the second control to the third control. vehicle.   The hybrid vehicle according to any one of claims 1 to 3, wherein the control device calculates the required output based on a vehicle speed, an accelerator opening, and a required driving force required for the vehicle. The variable valve operating device is configured to be capable of changing a maximum value of at least one of a lift amount and a working angle of the intake valve into three stages of first to third values,
The first to third values are set such that the second value is larger than the first value, and the third value is larger than the second value.
During execution of the second control, the control device sets the maximum value of at least one of the lift amount and the operating angle of the intake valve when the required driving force required for the vehicle is greater than a predetermined value. The value of 1 is set, and when the required driving force is smaller than a predetermined value, the maximum value of at least one of the lift amount and the operating angle of the intake valve is set to the third value. Hybrid vehicle. The variable valve operating device is configured to be capable of changing a maximum value of at least one of a lift amount and a working angle of the intake valve into two stages of first and second values,
The first and second values are set so that the second value is larger than the first value.
During execution of the second control, the control device sets the maximum value of at least one of the lift amount and the operating angle of the intake valve when the required driving force required for the vehicle is greater than a predetermined value. The value of 1 is set, and when the required driving force is smaller than a predetermined value, the maximum value of at least one of the lift amount and the operating angle of the intake valve is set to the second value. Hybrid vehicle.

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