JP2010195308A - Controller for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a hybrid vehicle securing startability upon starting an engine based on the operation of an ignition switch, and reducing vibration upon starting the engine based on the switching request of a traveling mode. <P>SOLUTION: The controller for a hybrid vehicle is applied to a hybrid vehicle that is configured to switch a traveling mode between a first traveling mode in which a vehicle travels by driving only a motor and a second traveling mode in which the vehicle travels by driving at least an internal combustion engine between the internal combustion engine and the motor, wherein the internal combustion engine includes a variable valve mechanism, and the variable valve mechanism includes a regulation mechanism for fixing a valve timing to an intermediate angle INVTmid. The controller for the hybrid vehicle is configured to, when the internal combustion engine is started based on the switching of an IG from OFF to ON, hold the valve timing to an intermediate angle INVTmid, and to, when the internal combustion engine is re-started based on a request for switching the first traveling mode to the second traveling mode, hold the valve timing INVT to the delay angle side of the intermediate INVTmid. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides a travel mode between a first travel mode in which only a motor among the internal combustion engine and the motor travels as a power source and a second travel mode in which at least the internal combustion engine and the motor travels with the internal combustion engine as a power source. The present invention relates to a control device for a hybrid vehicle to be switched.

  In a hybrid vehicle, an internal combustion engine is started based on an operation of switching an ignition switch from off to on, and an internal combustion engine is started based on establishment of an automatic start condition associated with a change in a vehicle running state or the like (see Patent Document 1). ).

JP 2007-303308 A

  By the way, when the vehicle travel mode is switched from the first travel mode in which the vehicle travels using only the motor as a power source to the second travel mode in which the vehicle travels using at least the internal combustion engine as a power source, the following becomes a problem. That is, in this case, since the state in which only the motor having a small vibration is driven is shifted to the state in which the internal combustion engine that generates a larger vibration is driven, the transition from the first traveling mode to the second traveling mode is performed. Therefore, the vibration generated when the engine is started may give the driver a sense of incongruity.

  Therefore, in order to reduce the vibration at the time of starting the engine, it may be possible to decompress the intake valve by retarding the valve timing of the intake valve. However, the delay of the valve timing is high when the engine is cold, etc. Since this is disadvantageous in situations where performance is required, simply delaying the valve timing leaves a problem in terms of practicality.

  On the other hand, as shown in Patent Document 1, for example, an internal combustion engine in which the valve timing of the intake valve is set in advance in order to ensure startability at a low temperature of the engine has been proposed. When the valve timing for decompression is uniformly applied, the startability is inevitably lowered.

  The present invention has been made in view of such circumstances, and ensures startability at the time of starting the engine based on the operation of the ignition switch and reduces vibration at the time of engine start based on the request for switching the travel mode. An object of the present invention is to provide a control device for a hybrid vehicle that can achieve both of these.

In the following, means for achieving the above object and its effects are described.
The invention according to claim 1 includes a first traveling mode in which only the motor of the internal combustion engine and the motor is driven as a power source, and a second traveling mode in which the vehicle is driven with at least the internal combustion engine of the internal combustion engine and the motor as a power source. The hybrid engine has a variable valve mechanism that changes the valve timing of the intake valve, and the variable valve mechanism has the latest valve timing of the intake valve. In a hybrid vehicle control device having a restriction mechanism that is fixed to an intermediate angle set between an angle and a most advanced angle, the intake valve at the time of starting the internal combustion engine based on a request to switch an ignition switch from off to on The valve timing is maintained at the intermediate angle by the restriction mechanism, and the travel mode is the first travel mode. It is summarized as to hold the valve timing of the intake valve at the start of the internal combustion engine based on the request to switch to et the second drive mode to the retard side of the intermediate angle.

  According to the present invention, when the engine is started based on a request to switch the ignition switch from off to on, the valve timing is held at the intermediate angle by the restriction mechanism, so that the intake air amount can be secured and the startability can be improved. become able to. In addition, when starting the engine based on a request to switch the running mode, the valve timing is not fixed by the restriction mechanism and is held on the retard side rather than the intermediate angle. Engine vibration can be reduced. That is, it is possible to achieve both of ensuring the startability at the time of engine start based on the operation of the ignition switch and reducing the vibration at the time of engine start based on the travel mode switching request.

The schematic diagram which shows typically the structure of the vehicle about embodiment which actualized the hybrid vehicle of this invention. (A) The top view which shows the planar structure about the valve timing variable mechanism which comprises the hybrid vehicle of the embodiment. (B) Sectional drawing which shows the cross-sectional structure which follows II of Fig.2 (a) about the valve timing variable mechanism. (C) Sectional drawing which shows the cross-sectional structure which follows II-II of the figure (a) about the valve timing variable mechanism. (A) The hybrid vehicle of the embodiment WHEREIN: The schematic diagram which shows the valve timing of an intake valve when operating an ignition switch from OFF to ON. (B) The schematic diagram which shows the valve timing of the intake valve at the time of restart of an internal combustion engine in the driving | running state of the hybrid vehicle of the embodiment, when switching from a 1st driving mode to a 2nd driving mode. The flowchart which shows the process sequence about the 1st phase setting process performed by the electronic controller in the hybrid vehicle of the embodiment. The flowchart which shows the process sequence about the 2nd phase setting process performed by the electronic controller in the hybrid vehicle of the embodiment.

With reference to FIGS. 1 to 5, an embodiment embodying a control device for a hybrid vehicle (hereinafter, “vehicle”) of the present invention will be described.
The vehicle is provided with a hybrid system S that switches a power source used for traveling. The hybrid system S includes an internal combustion engine 1 driven by combustion of an air-fuel mixture, an electric motor 2 that functions as a generator and a motor, a power switching mechanism 3 that switches a power transmission mode of the internal combustion engine 1 and the electric motor 2, and the power A transmission 4 that changes the speed of rotation input from the switching mechanism 3 and transmits it to the wheels. In addition, the vehicle is provided with an electronic control unit 90 that comprehensively controls various devices including the hybrid system S.

  The internal combustion engine 1 is provided with a cylinder block 12 constituting a plurality of cylinders. A piston 13 is provided in each cylinder. The piston 13 is connected via a connecting rod 19 to a crankshaft 18 provided at the lower part of the cylinder block 12.

A cylinder head 11 is provided above the cylinder block 12. A combustion chamber 14 is formed surrounded by the bottom surface of the cylinder head 11 and the upper end surface of the piston 13.
The cylinder head 11 is provided with an intake passage 16 and an exhaust passage 17 that communicate with the combustion chamber 14. Air taken in from the outside is drawn into the combustion chamber 14 via the intake passage 16. The amount of intake air flowing through the intake passage 16 is adjusted according to the opening of the throttle valve. Exhaust gas generated in the combustion chamber 14 is discharged to the outside of the vehicle through the exhaust passage 17.

  The cylinder head 11 is provided with a fuel injection valve 20. The fuel injection valve 20 is opened in response to a command from the electronic control unit 90 to inject and supply fuel. The fuel injected from the fuel injection valve 20 is mixed with intake air to form an air-fuel mixture. The cylinder head 11 is provided with a spark plug 15 that ignites the air-fuel mixture in the combustion chamber 14. Furthermore, the cylinder head 11 is provided with an intake valve 30 and an exhaust valve 36 that open and close the intake port and the exhaust port, respectively.

  An intake camshaft 31 and an exhaust camshaft 37 that open and close each of the intake valve 30 and the exhaust valve 36 are provided on the upper portion of the cylinder head 11. The intake camshaft 31 and the exhaust camshaft 37 are connected to the crankshaft 18 by a timing belt. That is, the intake valve 30 and the exhaust valve 36 are driven to open and close by the rotation of the intake camshaft 31 and the exhaust camshaft 37, and the intake port, the exhaust port, and the combustion chamber 14 are communicated or blocked. The cylinder head 11 is provided with a variable valve timing mechanism 40 that changes the valve timing INVT of the intake valve 30.

  The electric motor 2 includes a motor that functions as a generator and a power device, and a power storage device that stores the generated electric power and supplies the electric power to the motor. When the vehicle starts to run or accelerates, it is used as a power unit that drives wheels by a motor. On the other hand, when the vehicle shifts from a running state to a stopped state, it is used as a generator that generates electricity with a motor.

The power switching mechanism 3 switches the power transmission mode among the internal combustion engine 1, the electric motor 2, and the transmission 4 according to the vehicle running state and the charging state of the power storage device.
The electronic control unit 90 performs arithmetic processing based on detection signals from various sensors such as the crank position sensor 91, the cam position sensor 92, and the outside air temperature sensor 93, and controls the operation mode of the hybrid system S based on the calculation results. Hybrid control is performed. The crank position sensor 91 is provided in the vicinity of the crankshaft 18 and outputs a signal corresponding to the rotation angle of the crankshaft 18. The cam position sensor 92 is provided in the vicinity of the intake camshaft 31 and outputs a signal corresponding to the rotation angle of the intake camshaft 31. The outside air temperature sensor 93 outputs a signal corresponding to the outside air temperature (hereinafter, “outside air temperature TA”).

  The main control modes of the hybrid system S by hybrid control are shown below. The system is activated when the ignition switch IG is switched from OFF to ON, and is shut off when the switch is switched from ON to OFF.

  (A): When it is detected that the ignition switch IG is switched from OFF to ON, both the internal combustion engine 1 and the electric motor 2 are driven. In this case, when a vehicle start request is not detected, the power of the electric motor 2 is transmitted only to the internal combustion engine 1 to promote warm-up of the engine. When the internal combustion engine 1 is warmed up and the battery is fully charged, the operation of the internal combustion engine 1 is stopped.

  (B): When a start request is detected by operating the accelerator pedal in the idling state of the vehicle, only the power of the electric motor 2 is transmitted to the transmission 4 and the internal combustion engine 1 is kept stopped. That is, the vehicle is started only by the power of the electric motor 2.

  (C): When the vehicle is traveling at a low load, only the power of the electric motor 2 is transmitted to the transmission 4 and the internal combustion engine 1 is kept stopped. That is, the vehicle is driven only by the power of the electric motor 2.

  (D): When the vehicle is traveling at a medium load, the operation of the internal combustion engine 1 is started and the power of the internal combustion engine 1 is transmitted to the transmission 4. In addition, transmission of power from the electric motor 2 to the transmission 4 is cut off. That is, the vehicle is driven only by the power of the internal combustion engine 1.

  (E): When the acceleration request of the vehicle is detected, the power of the electric motor 2 is transmitted to the transmission 4 together with the power of the internal combustion engine 1. That is, the vehicle is driven by the power of the internal combustion engine 1 and the electric motor 2.

  Thus, in the hybrid vehicle, in addition to starting and stopping the internal combustion engine 1 based on the operation of the ignition switch IG, the internal combustion engine 1 is started and stopped according to the vehicle running state. Hereinafter, the start of the internal combustion engine 1 that is performed based on the ignition switch IG being switched from OFF to ON is referred to as “normal start”. Further, the stop of the internal combustion engine 1 performed based on the ignition switch IG being switched from on to off is referred to as “normal stop”. In addition, “automatic start” refers to the start of the internal combustion engine 1 that is performed without being based on the operation of the ignition switch IG with the ignition switch IG being on, that is, the start of the internal combustion engine 1 that is performed based on the establishment of the automatic start condition. And Moreover, the stop of the internal combustion engine 1 that is performed without being based on the operation of the ignition switch IG with the ignition switch IG being on, that is, the stop of the internal combustion engine 1 that is performed based on the establishment of the automatic stop condition is “automatic stop”. And

  Examples of the automatic stop condition include that the vehicle speed is lower than the reference speed while the vehicle is traveling and that the vehicle shifts to an idle state. Examples of the automatic start condition include that the vehicle speed exceeds the reference speed while the vehicle is traveling, that the accelerator pedal is depressed in the idle state of the vehicle, and that the power storage device needs to be charged. .

  Here, in the hybrid vehicle, the traveling mode is changed to the next first traveling mode and the second traveling mode by stopping and starting the internal combustion engine 1 based on the automatic stop condition and the automatic start condition during the traveling. Can be classified.

  The first traveling mode is a mode in which only the latter power of the internal combustion engine 1 and the electric motor 2 is transmitted to the wheels via the transmission 4, that is, a mode in which the vehicle travels only by the power of the electric motor 2. This travel mode occurs when the hybrid control (B) or (C) is performed, for example.

  The second traveling mode is a mode in which at least the former power of the internal combustion engine 1 and the electric motor 2 is transmitted to the wheels via the transmission 4, that is, the vehicle is driven by the power of the internal combustion engine 1 or the internal combustion engine 1 and the electric motor 2. A mode in which the vehicle travels with both powers is shown. This travel mode occurs when the hybrid control (D) or (E) is performed, for example.

  That is, when the automatic start condition is satisfied when the hybrid vehicle is in the first travel mode, the travel mode shifts from the first travel mode to the second travel mode as the internal combustion engine 1 is automatically started. Further, when the hybrid vehicle is in the second travel mode, when the automatic stop condition is satisfied and there is a travel request for the vehicle, the travel mode is changed from the second travel mode to the second travel mode. Transition to 1 driving mode. Therefore, the state in which the automatic start condition is established while the vehicle is traveling can be regarded as a state in which a request for switching the traveling mode from the first traveling mode to the second traveling mode has occurred.

  With reference to FIG. 2, the configuration of the variable valve timing mechanism 40 of the internal combustion engine 1 will be described. 2A shows a planar structure of the variable valve timing mechanism 40, FIG. 2B shows a cross-sectional structure taken along line II in FIG. 2A, and FIG. The cross-sectional structures along the line II-II in (a) are respectively shown.

  The variable valve timing mechanism 40 adjusts the relative rotation phase of the intake camshaft 31 with respect to the rotation phase of the crankshaft 18 to change the valve timing INVT of the intake valve 30. That is, the valve timing INVT is continuously changed between the most advanced timing (hereinafter, “most advanced angle INVTmax”) and the most retarded timing (hereinafter, “most delayed angle INVTmin”).

The variable valve timing mechanism 40 is provided with a lock mechanism 60 that fixes the valve timing INVT to a predetermined phase. Hereinafter, a specific structure will be described.
As shown in FIG. 2A, the variable valve timing mechanism 40 is provided coaxially with the sprocket 46 that rotates in synchronization with the crankshaft 18 and the intake camshaft 31 and rotates relative to the sprocket 46. A vane rotor 51 and a housing 41 that houses the vane rotor 51 are provided.

  The sprocket 46 is drivingly connected to the crankshaft 18 via a timing belt, and rotates in synchronization with the crankshaft 18. The vane rotor 51 includes a rotor main body 53 and three vanes 52 formed to protrude from the rotor main body 53 in the radial direction. The housing 41 includes a housing body 42 and a cover 43 and is fastened to the sprocket 46. And it rotates integrally with the sprocket 46. The housing main body 42 is provided with three accommodation chambers 44 in which the vanes 52 of the vane rotor 51 are accommodated. These storage chambers 44 are separated by a partition wall 45. Each storage chamber 44 is divided into a retard hydraulic chamber 55 and an advanced hydraulic chamber 56 by a vane 52.

  The vane rotor 51 rotates to the retard side when the hydraulic oil is supplied to the retard hydraulic chamber 55 and the hydraulic oil is discharged from the advance hydraulic chamber 56. When the vane rotor 51 rotates to the most retarded phase, the valve timing INVT becomes the most retarded INVTmin. On the other hand, when the hydraulic oil is discharged from the retarded hydraulic chamber 55 and supplied to the advanced hydraulic chamber 56, the vane rotor 51 rotates to the advanced side. When the vane rotor 51 rotates to the most advanced phase, the valve timing INVT becomes the most advanced angle INVTmax.

  The lock mechanism 60 includes an intermediate lock pin 61 and a lock hole 62. The intermediate lock pin 61 fixes the vane rotor 51 to the sprocket 46 at a rotational phase corresponding to an intermediate angle phase between the vane rotor 51 and the most advanced angle phase. The intermediate lock pin 61 is provided on a predetermined vane 52 so as to protrude in a direction along the rotation axis of the vane rotor 51, and is always urged in a direction protruding from the vane 52 by an urging spring (not shown). In addition, a lock pin working chamber is formed at the tip of the intermediate lock pin 61 to apply hydraulic pressure of the working oil. On the other hand, the sprocket 46 is formed with a lock hole 62 in which the intermediate lock pin 61 is fitted so as to face the position of the intermediate lock pin 61 when the vane rotor 51 rotates to the intermediate angle phase. Further, the lock hole 62 is provided with a stepped portion 63 for enlarging the opening 62a to the retarded angle side.

  The intermediate lock pin 61 protrudes from the vane 52 by the urging force of the urging spring when the hydraulic pressure in the advance hydraulic chamber 56 decreases as the oil pump stops due to the stop of the internal combustion engine 1. When the vane rotor 51 rotates to the rotation phase corresponding to the intermediate angle phase, the intermediate lock pin 61 is fitted into the lock hole 62 and the vane rotor 51 is fixed.

  On the other hand, when the operation of the internal combustion engine 1 is stopped in a state where the intermediate lock pin 61 is not fitted in the lock hole 62, the intermediate lock pin 61 is fitted in the lock hole 62 as follows when the engine is subsequently started. .

  That is, when the engine is started, the intermediate lock pin 61 is pressing the bottom surface of the sprocket 46 so as to protrude from the vane rotor 51 by the biasing spring. When cranking is started by operating the ignition switch IG, the valve timing variable mechanism 40 does not have sufficient hydraulic pressure, so the vane rotor 51 swings as the crankshaft 18 rotates. When the phase of the intermediate lock pin 61 moves to a position corresponding to the step portion 63 along with the swing of the vane rotor 51, the intermediate lock pin 61 fits into the step portion 63. Further, as the vane rotor 51 swings in this state, the intermediate lock pin 61 is fitted into the lock hole 62. The advance method for fitting the intermediate lock pin 61 into the lock hole 62 by utilizing the swing of the vane rotor 51 during cranking is referred to as “self-supporting advance angle”.

  With reference to FIG. 3, the control of the valve timing INVT at the time of engine start will be described. FIG. 3A shows the valve timing INVT at the normal start, and FIG. 3B shows the valve timing INVT at the automatic start. In the figure, “TDC” is the top dead center of the piston 13, “BDC” is the bottom dead center of the piston 13, “IVO” is the opening timing of the intake valve 30, and “IVC” is the intake valve 30. Each valve closing time is shown.

In an environment where the outside air temperature TA is lower than a predetermined cold temperature TX (for example, −10 ° C.), the engine startability tends to be remarkably lowered.
Therefore, at the normal start, the valve timing INVT is set to the intermediate angle INVTmid shown in FIG. As a result, the intake air amount increases as compared with the case where the valve timing INVT is set to the retard side (for example, the most retarded angle INVTmin) with respect to the intermediate angle INVTmid, so that the engine startability can be improved. become.

  The intermediate angle INVTmid is a valve timing INVT between the most advanced angle INVTmax and the most retarded angle INVTmin, and the valve closing timing of the intake valve 30 is set near the bottom dead center and on the more retarded side than this. Here, the intermediate angle INVTmid is set in advance so as to obtain an intake air amount necessary for ensuring good startability in an environment where the outside air temperature TA is lower than the cold temperature TX.

  On the other hand, in an environment where the outside air temperature TA is equal to or higher than the cold temperature TX, the startability at the time of normal starting as described above is unlikely to occur, and therefore, the valve timing INVT is the most retarded angle that is more retarded than the intermediate angle INVTmid. It is allowed to set INVTmin.

  Therefore, at the normal start time when the outside air temperature TA is equal to or higher than the cold temperature TX and the valve timing INVT is not fixed to the intermediate angle INVTmid, the valve timing INVT is set to the most retarded angle INVTmin shown in FIG. I am doing so. As a result, the operation of decompression in the cylinder becomes larger compared to the case where the valve timing INVT is set to an advance side of the most retarded angle INVTmin (for example, the intermediate angle INVTmid). The vibration associated with the operation can be reduced.

  On the other hand, when the internal combustion engine 1 is automatically started, the engine is warmed up more than when it is normally started. Therefore, even if the outside air temperature TA is low, the startability is not greatly reduced. In addition, since the engine is started without the operation of the ignition switch IG by the driver from the state where the operation of the internal combustion engine 1 is stopped, from the viewpoint of reducing the discomfort to the driver, It can be said that it is desirable to reduce the engine vibration.

  Therefore, when automatic start is performed, the valve timing INVT is set to the most retarded angle INVTmin shown in FIG. As a result, the operation of decompression in the cylinder becomes larger compared to the case where the valve timing INVT is set to an advance side of the most retarded angle INVTmin (for example, the intermediate angle INVTmid). The vibration associated with the operation can be reduced.

  With reference to FIG. 4, the content of the “first phase setting process” that defines a specific processing procedure of the valve timing control at the normal start will be described. This process is repeatedly executed by the electronic control unit 90 every predetermined control period set in advance.

  When it is determined in step S10 that the ignition switch IG has been switched from OFF to ON, and in step S11, it is determined that the valve timing INVT is fixed to the intermediate angle INVTmid, the intermediate angle INVTmid is determined in step S12. Is maintained and the internal combustion engine 1 is started.

  When it is determined in step S10 that the ignition switch IG has been switched from OFF to ON, and it is determined in step S11 that the valve timing INVT is not fixed at the intermediate angle INVTmid, the outside air temperature TA is determined in step S13. Is determined to be equal to or higher than the cold temperature TX. Note that the cold temperature TX corresponds to the boundary value of the outside air temperature TA when good engine startability is not secured as the outside air temperature TA decreases when the valve timing INVT is set to the most retarded angle INVTmin. Yes, it is set in advance through testing.

  In step S13, when it is determined that the outside air temperature TA is lower than the cold temperature TX, first, cranking is executed, and the internal combustion engine until the valve timing INVT is fixed to the intermediate angle INVTmid by the self-advanced advance angle of the valve timing variable mechanism 40. The start of the engine 1 is suspended. When the confirmation is obtained, the engine is started based on the ON operation of the ignition switch IG.

  When it is determined in step S13 that the outside air temperature TA is equal to or higher than the cold temperature TX, the internal combustion engine 1 is in a state where a command for setting the valve timing INVT to the most retarded angle INVTmin is transmitted to the valve timing variable mechanism 40. Start.

  With reference to FIG. 5, the content of the “second phase setting process” that defines a specific processing procedure for valve timing control during engine operation and engine stop will be described. This process is repeatedly executed by the electronic control unit 90 every predetermined control period set in advance.

  In step S20, it is determined that the ignition switch IG has been switched from on to off, that is, it is determined that there is a request to shut off the hybrid system S, and in step S26, it is determined that the internal combustion engine 1 is in an operating state. At the time, the valve timing INVT is changed to the intermediate angle INVTmid prior to the engine stop based on the turning-off operation of the ignition switch IG, and then the operation of the internal combustion engine 1 is stopped and the hybrid system S is shut off. When the hybrid system S is shut off through this sequence, the internal combustion engine 1 is normally started with the valve timing INVT set to the intermediate angle INVTmid.

  On the other hand, when it is determined in step S20 that the ignition switch IG has been switched from on to off, and in step S26, it is determined that the internal combustion engine 1 is stopped, the hybrid system without changing the valve timing INVT. Block S.

  That is, when the ignition switch IG is switched from on to off after the internal combustion engine 1 is automatically stopped by the processing in step S25 described later, the hybrid system S is maintained by maintaining the valve timing INVT at that time. Cut off. When the hybrid system S is shut down through this sequence, when the outside air temperature TA is lower than the cold temperature TX at the next normal start of the internal combustion engine 1, the valve timing INVT by the self-standing advance angle of the valve timing variable mechanism 40 is changed. A change to the intermediate angle INVTmid is made. If the outside air temperature TA is equal to or higher than the cold temperature TX at the next normal start of the internal combustion engine 1, the engine is started in a state where a command for setting the valve timing INVT to the most retarded angle INVTmin is transmitted.

  When it is not determined in step S20 that the ignition switch IG is switched from on to off, that is, it is determined that there is no request for shutting off the hybrid system S, and when it is determined in step 21 that the internal combustion engine 1 is in a stopped state, In S22, it is determined whether or not the automatic start condition is satisfied. When it is determined that the automatic start condition is satisfied, in step S23, the valve timing INVT is set to the most retarded angle INVTmin, and the internal combustion engine 1 is automatically started. In the phase setting process, since the valve timing INVT is set to the most retarded angle INVTmin when the internal combustion engine 1 is automatically stopped, the valve timing INVT is basically the most retarded at the time of automatic start. The state is set to INVTmin.

  On the other hand, when it is determined in step S21 that the internal combustion engine 1 is in an operating state, it is determined in step S24 whether an automatic stop condition is satisfied. When it is determined that the automatic stop condition is satisfied, the valve timing INVT is set to the most retarded angle INVTmin, and the internal combustion engine 1 is automatically stopped. Here, the valve timing INVT is set to the most retarded angle INVTmin prior to the engine stop based on the establishment of the automatic stop condition, and then the operation of the internal combustion engine 1 is stopped.

  Here, in a state where the hybrid vehicle is in the second travel mode, when it is determined by the processing in step S24 that the automatic stop condition is satisfied, the travel mode accompanying the automatic stop of the internal combustion engine 1 is changed from the second travel mode. Transition to the first travel mode. Thereafter, when it is determined in the process of step S22 that the automatic start condition is satisfied, the travel mode is shifted from the first travel mode to the second travel mode as the internal combustion engine 1 is automatically started.

  When the transition to the second traveling mode is performed based on the establishment of such an automatic start condition, as described above, the valve timing INVT is set to the most retarded angle INVTmin by the process of step S23. That is, the automatic start of the internal combustion engine 1 is started in a state where the valve timing INVT is set to the intermediate angle INVTmid. In other words, when the internal combustion engine 1 is started based on a request to switch the travel mode from the first travel mode to the second travel mode, the valve timing INVT is set to the most retarded angle INVTmin prior to this.

According to the hybrid vehicle of this embodiment, the following effects can be obtained.
(1) In the present embodiment, as performed in the first phase setting process, the valve timing INVT of the intake valve 30 is set to the lock mechanism 60 when the internal combustion engine 1 is started based on the ignition switch IG being switched from OFF to ON. To hold the intermediate angle INVTmid. Further, as performed in step S22 and step S23 of the second phase setting process, when the internal combustion engine 1 is started based on a request to switch the travel mode from the first travel mode to the second travel mode, the valve timing INVT of the intake valve 30 is determined. Is held on the retard side with respect to the intermediate angle INVTmid.

  Therefore, when the engine is started based on the ignition switch IG being switched from OFF to ON, the valve timing INVT is held at the intermediate angle INVTmid by the lock mechanism 60, so that the intake air amount is secured and the startability is improved. Will be able to. Further, when the engine is started based on the request to switch the running mode, the valve timing INVT is not fixed by the lock mechanism 60 and is held at the most retarded angle INVTmin that is retarded from the intermediate angle INVTmid. Thus, the engine vibration at the time of starting can be reduced. That is, it is possible to achieve both of ensuring startability at the time of engine start based on the operation of the ignition switch IG and reducing vibration at the time of engine start based on the request for switching the travel mode.

  (2) In the present embodiment, when the vehicle is in a state where the engine is stopped based on the operation of the ignition switch IG when the internal combustion engine 1 is automatically stopped, the outside air temperature TA should be equal to or higher than the cold temperature TX when starting normally. For example, the engine is started while the valve timing INVT is maintained at the most retarded angle INVTmin. That is, if the outside air temperature TA is equal to or higher than the cold temperature TX, the engine startability is ensured. Therefore, when the internal combustion engine 1 is automatically stopped, the engine is stopped based on the operation of the ignition switch IG, and the valve timing INVT is the most retarded angle. Even when the engine is set to INVTmin, starting is ensured and vibration during engine starting is reduced.

(Other embodiments)
The above embodiment can be modified as follows.
In the above-described embodiment, when the valve timing INVT is fixed to the intermediate angle INVTmid by the self-advanced advance angle during normal starting, the vane rotor 51 swings when a large amount of hydraulic oil stays in the retarded hydraulic chamber 55. Therefore, the valve timing INVT may not be fixed by the lock mechanism 60.

  Therefore, in order to cope with such a problem, the following control is performed when it is detected that the ignition switch IG is switched from on to off in a state where the valve timing INVT is set to the most retarded angle INVTmin. It can also be added. That is, the internal combustion engine 1 in a stopped state is once operated, and the valve timing variable mechanism 40 is advanced under this state, whereby the hydraulic oil is discharged from the retarded hydraulic chamber 55 and the valve timing variable mechanism 40 When it is estimated that the hydraulic oil has been sufficiently discharged based on the advance amount or the operating time, the operation of the internal combustion engine 1 is stopped and the hybrid system S is shut off.

  In the first phase setting process (FIG. 3) of the above embodiment, the valve timing INVT at the normal start is made different based on the comparison result between the outside air temperature TA and the cold temperature TX, but this is omitted. You can also That is, at the normal start time, the valve timing INVT may always be set to the intermediate angle INVTmid. According to this configuration, since the startability of the internal combustion engine 1 is set to a high state, the startability of the vehicle is not impaired even if the use environment of the vehicle changes.

  In the above embodiment, the valve timing INVT is set to the most retarded angle INVTmin when the internal combustion engine 1 is automatically started. However, the valve timing INVT at the time of automatic start is not limited to this. For example, any valve timing INVT between the most retarded angle INVTmin and the intermediate angle INVTmid can be set. Even when such a configuration is adopted, vibration at the time of engine start can be reduced as compared with a configuration in which the valve timing INVT is set to the intermediate angle INVTmid at the time of automatic start.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Electric motor, 3 ... Power switching mechanism, 4 ... Transmission, 11 ... Cylinder head, 12 ... Cylinder block, 13 ... Piston, 14 ... Combustion chamber, 15 ... Spark plug, 16 ... Intake passage, 17 ... exhaust passage, 18 ... crankshaft, 19 ... connecting rod, 20 ... fuel injection valve, 30 ... intake valve, 31 ... intake camshaft, 36 ... exhaust valve, 37 ... exhaust camshaft, 40 ... variable valve timing mechanism (possible) Fluctuating valve mechanism), 41 ... housing, 42 ... housing main body, 43 ... cover, 44 ... accommodating chamber, 45 ... partition wall, 46 ... sprocket, 51 ... vane rotor, 52 ... vane, 53 ... rotor main body, 55 ... retarding hydraulic chamber 56 ... Advance hydraulic chamber, 60 ... Lock mechanism (regulation mechanism), 61 ... Intermediate lock pin, 62 ... Lock hole, 62a ... Opening, 63 ... Step , 90 ... electronic control device (control device), 91 ... crank position sensor, 92 ... cam position sensor, 93 ... ambient temperature sensor.

Claims (1)

A hybrid vehicle in which a travel mode is switched between a first travel mode in which only the motor among the internal combustion engine and the motor travels using a power source and a second travel mode in which at least the internal combustion engine and the motor travels using the internal combustion engine as a power source. The internal combustion engine includes a variable valve mechanism that changes the valve timing of the intake valve, and the variable valve mechanism moves the valve timing of the intake valve between the most retarded angle and the most advanced angle. In the control apparatus for a hybrid vehicle that includes a restriction mechanism that fixes the intermediate angle that is set,
The valve timing of the intake valve is held at the intermediate angle by the restriction mechanism when the internal combustion engine is started based on a request to switch the ignition switch from off to on, and the travel mode is switched from the first travel mode to the second travel mode. A control apparatus for a hybrid vehicle, characterized in that the valve timing of the intake valve is held on the retard side with respect to the intermediate angle when the internal combustion engine is started based on demand.

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