JP2010203279A - Engine controller of hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine controller for a hybrid vehicle capable of reducing the pumping loss without putting cylinder(s) in pause. <P>SOLUTION: The engine controller of the hybrid vehicle 50 equipped as driving sources with an engine 1 having a fuel supplying means 21 and a motor 51, with which a regenerative control of the motor 51 is conducted when the vehicle is in deceleration, wherein the configuration comprises valve timing varying mechanisms 26 and 27 capable of adjusting the valve timing of a suction valve 15 changeably, a fuel cut condition determining means 31 to determine whether the fuel cut conditions are met, a fuel supply stopping means 31 to stop the fuel supply from the fuel supplying means 21 after the fuel cut conditions are met, and a valve timing changing means 31 to change the valve timing of the suction valve 15 in the direction of reducing the pumping loss using the valve timing varying mechanisms 26 and 27 while the fuel supply is stopped. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an engine control device for a hybrid vehicle, and more particularly to a device that includes a variable valve operating device and performs fuel cut when the vehicle is decelerated.

  In a hybrid vehicle, a motor is used as a generator when the vehicle decelerates, and the kinetic energy of the vehicle is converted into electric energy and collected in a battery. If the engine and the motor are in a direct connection state during the regeneration control of the motor, the regeneration efficiency is deteriorated by an amount corresponding to the pumping loss of the engine. In order to reduce the pumping loss of the engine at the time of regenerative control, there is one that performs cylinder deactivation (see Patent Document 1).

Japanese Patent No. 3540297

  By the way, in the technique described in Patent Document 1, a variable valve timing mechanism using a drive source as a hydraulic source is provided, and by using the variable valve timing mechanism, the intake valve and the exhaust valve are kept closed. Pumping loss is reduced.

  However, when shifting from cylinder operation to cylinder deactivation when the vehicle decelerates, a shock due to torque fluctuation occurs, and when shifting from cylinder deactivation to cylinder operation during recovery from a fuel cut, the torque variation also causes A shock occurs.

  Therefore, an object of the present invention is to provide an apparatus that can reduce the pumping loss without performing cylinder deactivation.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

  The present invention provides an engine control device for a hybrid vehicle (50) that includes an engine (1) having a fuel supply means (21) and a motor (51) as drive sources, and performs regenerative control of the motor (51) during vehicle deceleration. , A valve timing variable mechanism (26, 27) capable of variably adjusting the valve timing of the intake valve (15) is determined, and it is determined whether or not the fuel cut condition is satisfied, and fuel is supplied after the fuel cut condition is satisfied. The fuel supply from the means (21) is stopped, and the valve timing of the intake valve (15) is changed in such a direction that the pumping loss is reduced using the variable valve timing mechanism (26, 27) while the fuel supply is stopped. Configure.

  According to the present invention, a valve timing of an intake valve can be variably adjusted in an engine control device of a hybrid vehicle that includes an engine having a fuel supply means and a motor as drive sources and performs regenerative control of the motor during vehicle deceleration. A variable valve timing mechanism is provided to determine whether or not a fuel cut condition is satisfied. After the fuel cut condition is satisfied, the fuel supply from the fuel supply means is stopped, and the valve timing variable mechanism is stopped while the fuel supply is stopped. Is used to change the valve timing of the intake valve in the direction of reducing pumping loss, so it is possible to reduce pumping loss without cylinder deactivation. The regeneration efficiency at the time can be improved.

1 is an overall configuration diagram of a hybrid vehicle according to a first embodiment of the present invention. It is a schematic block diagram of an engine control apparatus. 4 is a timing chart showing changes in intake valve opening timing, intake valve closing timing, throttle valve opening, and fuel injection state during fuel cut in the first embodiment. It is a flowchart for demonstrating the control at the time of the fuel cut of 1st Embodiment. 6 is a timing chart showing changes in intake valve opening timing, intake valve closing timing, throttle valve opening, and fuel injection state during fuel cut according to the second embodiment. It is a flowchart for demonstrating the control at the time of the fuel cut of 2nd Embodiment.

  FIG. 1 is an overall configuration diagram of a hybrid vehicle according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of an engine control device.

  First, the engine control device shown in FIG. 2 will be described briefly. Air is metered by the throttle valve 23 upstream of the intake collector 2 and supplied to the combustion chamber 5 of the engine 1. The fuel is injected from the fuel injection valve 21 (fuel supply means) toward the intake port 4 of the intake manifold 3, carried to the intake air flowing through the intake port 4, and introduced into the combustion chamber 5. The fuel spray from the fuel injection valve 21 is vaporized to form an air-fuel mixture in the combustion chamber 5, and the gas in the combustion chamber 5 is compressed by the piston 6 after the intake valve 15 is closed. Then, combustion is performed by ignition by the spark plug 14, and the burned gas exits to the exhaust passage 8 when the exhaust valve 16 is opened and is purified by the three-way catalysts 9 and 10 in the exhaust passage 8.

  The throttle valve 23 is driven by a throttle motor 24. Since the torque required by the driver appears in the amount of depression of the accelerator pedal 41 (accelerator opening), the engine controller 31 determines a target torque based on a signal from the accelerator sensor 42, and a target air for realizing this target torque. The amount is determined, and the opening degree of the intake throttle valve 23 is controlled via the throttle motor 24 so that this target air amount is obtained. As will be described later, in the hybrid vehicle, the signal from the accelerator sensor 81 is input to the AT controller 71.

  The engine 1 includes a variable valve mechanism (hereinafter referred to as a “VEL mechanism”) 26 configured by a multi-node link mechanism that continuously and variably controls the valve lift amount and the operating angle of the intake valve 15, and the crankshaft 7. And a variable valve timing mechanism (hereinafter referred to as “VTC mechanism”) 27 that advances and retards the valve timing of the intake valve 15 by continuously variably controlling the rotational phase difference between the intake valve camshaft 25 and the intake valve camshaft 25. By using the VEL mechanism 26 and the VTC mechanism 27 (variable valve timing mechanism), the opening timing IVO and the closing timing IVC of the intake valve 15 can be arbitrarily controlled.

  An intake air amount signal from the air flow meter 32, a crank angle signal from the crank angle sensors 33 and 34, a cooling water temperature signal from the water temperature sensor 37, an air / fuel ratio signal from the air / fuel ratio sensor 35 upstream of the catalyst, a catalyst The engine controller 31 to which an oxygen concentration signal from a downstream oxygen concentration sensor (not shown) is input controls the fuel injection from the fuel injection valve 21 and the ignition timing by the spark plug 14. Specifically, in the fuel injection control, the fuel injection amount from the fuel injection valve 21 is controlled so that the air-fuel ratio of the exhaust gas flowing through the three-way catalysts 9 and 10 is within a window centered on the stoichiometric air-fuel ratio. Further, the engine controller 31 uses the VEL mechanism 26 and the VTC mechanism 27 as valve timing changing means, and variably controls (changes) the valve timing of the intake valve 15 according to the operating conditions. Further, in order to improve fuel efficiency, the engine controller 31 performs fuel cut to stop fuel injection from the fuel injection valve 21 when the vehicle is decelerated.

  In FIG. 1, the hybrid vehicle is a so-called one-motor / two-clutch hybrid vehicle (parallel type) 50. That is, the 1-motor / 2-clutch hybrid vehicle 50 includes an engine 1 and a motor 51 (motor generator) as a drive source, a transmission 53 that transmits power from the drive source to drive wheels, an engine 1 and a motor 53. A first clutch 54 that can be connected and disconnected and a second clutch 55 that can connect and disconnect the motor 51 and the transmission 53 are provided. More specifically, the engine rotation shaft 56 (= crankshaft 7) is connected to the motor rotation shaft 57 via the first clutch 54, and the motor rotation shaft 57 is connected to the input side rotation shaft 58 of the transmission 53. Yes. The input side rotation shaft 58 is connected to the output side rotation shaft 59 of the transmission 53 via the second clutch 55. The output-side rotary shaft 59 is connected to drive wheels 61 and 61 via a differential gear device 60.

  A signal from the accelerator sensor 81 that detects the amount of depression of the accelerator pedal, a signal from the vehicle speed sensor 82 that detects the vehicle speed of the vehicle, and a signal from the rotation speed sensor 83 that detects the rotation speed of the input side rotating shaft 58 of the transmission 53. Is input to the AT controller 71, and the connection / disconnection between the transmission 53 and the second clutch 55 is controlled. A motor controller 72 to which a signal from a rotation speed sensor 84 that detects the rotation speed of the motor rotation shaft 57 is input controls the motor 51 via an inverter 73. The first clutch controller 74 controls connection / disconnection of the first clutch 54.

  The engine controller 31, the AT controller 71, the motor controller 72, the first clutch controller 74, and the integrated controller 75 are in communication with each other through a CAN 76. The integrated controller 75 communicates with the four controllers 31, 71, 72, and 74 to control the hybrid vehicle so as to obtain driving according to the driving state of the vehicle. For example, when the vehicle starts running from the vehicle stop state, the engine 1 is not started, and the vehicle is driven by the motor 51 with the second clutch 55 engaged. On the other hand, when it is determined that the accelerator pedal is further depressed while the vehicle is being driven by the motor 51 and the driver has requested acceleration, the first clutch 54 is engaged and the engine 1 is started. Respond to driver acceleration demand by adding driving force. Further, when the vehicle is decelerated, the first clutch 54 is opened and the motor 51 is used as a generator to convert the power from the drive shaft (kinetic energy of the vehicle) into electric energy and collect it in the battery 77. In addition, so-called idle stop control that automatically stops the engine 1 regardless of the driver's intention when the engine automatic stop condition is satisfied, and automatically restarts the engine 1 when the engine restart condition is satisfied thereafter. Is also going.

  FIG. 3 shows how the fuel cut flag, the intake valve opening timing IVO, the intake valve closing timing IVC, the throttle valve opening, and the fuel injection state change when the vehicle is decelerated. Here, with regard to the intake valve opening timing IVO and the intake valve closing timing IVC, the case of the current control is indicated by a one-dot chain line, and the case of the present invention is indicated by a solid line.

  First, the case of current control will be described first. When the accelerator pedal 41 is depressed, the engine rotational speed is in a rotational speed region that is equal to or higher than the fuel cut rotational speed Ncut. When the driver releases the accelerator pedal 41 to start deceleration of the vehicle in this rotational speed region, the fuel cut condition is satisfied. To do. Assume that the fuel cut condition is satisfied at the timing t0 and the fuel cut flag is switched from zero to one. On the other hand, it is assumed that the fuel cut recovery condition is satisfied at the timing of t2. For example, when the accelerator pedal 41 is depressed for re-acceleration in a state where the engine rotation speed has not decreased to the fuel cut recovery rotation speed Nrcv, or without the accelerator pedal 41 being depressed, the engine rotation speed is reduced to the fuel cut recovery rotation. The fuel cut recovery condition is met when the speed Nrcv drops across. Therefore, the fuel cut period is a period from t0 to t2.

  Before the fuel cut before t0 and after the fuel cut recovery from t2, the intake valve opening timing IVO, the intake valve closing timing IVC, and the throttle valve opening TVO are set to optimum values according to the operating conditions at that time. Therefore, here, the intake valve opening timing IVO, the intake valve closing timing IVC, and the throttle valve opening TVO before the fuel cut are set to the first predetermined value IVO1, the first predetermined value IVC1, and the first predetermined value TVO1, respectively. The intake valve opening timing IVO, the intake valve closing timing IVC, and the throttle valve opening TVO after the cut recovery are set to a second predetermined value IVO2, a second predetermined value IVC2, and a second predetermined value TVO2, respectively.

  Rather than immediately stopping the fuel supply at the timing t0 when the fuel cut condition is satisfied, the third predetermined value close to zero from the first predetermined value TVO1 that is the value immediately before the fuel cut is set to the throttle valve opening TVO from the timing t0. The fuel injection is continued while decreasing (changing) to the value TVO3. Thus, after the throttle valve 23 is throttled, the fuel injection is stopped at the timing t1 when the air remaining in the intake passages (2, 3) downstream of the throttle valve 23 has decreased (the amount of air flowing into the combustion chamber 5 has decreased).

In this way, the fuel injection is continued until the timing (t1) when the throttle valve 23 is throttled and the air remaining in the intake passage downstream of the throttle valve 23 is reduced from the timing (t0) when the fuel cut condition is satisfied. The reason why the cut is delayed for a predetermined period is to suppress the generation of NOx. More specifically, in the three-way catalysts 9 and 10 having an oxygen storage function (a function for storing oxygen), the oxygen stored in the HC and CO is released (that is, oxidized), whereby the HC and CO are converted into H. _While detoxifying to ₂ O and CO ₂ , NOx is detoxified to N ₂ by depriving (ie, reducing) oxygen from NOx. For this reason, by stopping the fuel supply from the fuel injection valve 21 while the throttle valve 23 is open even if the fuel cut condition is satisfied, oxygen in the fresh air (in air) is supplied to the three-way catalysts 9 and 10. If the gas is stored to a full extent, oxygen cannot be deprived from the NOx in the exhaust immediately after the recovery from the fuel cut, that is, the NOx reducing ability is reduced. Therefore, by closing the throttle valve 23 and continuing fuel injection until the amount of air into the combustion chamber 5 is reduced, the storage oxygen amount of the three-way catalysts 9 and 10 does not become full, so that NOx can be reduced. Keep it in a state. The period from the timing when the fuel cut condition is satisfied (t0) to the timing when the fuel supply is actually stopped (t1) is a period in which the actual fuel cut is delayed, that is, a fuel cut delay period.

  In the engine 1 including the VEL mechanism 26 and the VTC mechanism 27, although there is a limit, the intake valve opening timing IVO and the intake valve closing timing IVC can be arbitrarily controlled. Therefore, the valve timing of the intake valve 15 is changed for the purpose of improving the combustion state during the fuel cut delay period. That is, the intake valve opening timing IVO is changed to the third predetermined value IVO3 delayed from the intake top dead center TDC (the top dead center when moving from the exhaust stroke to the intake stroke) at the timing t0. The valve opening overlap period (hereinafter simply referred to as “valve overlap”) does not occur, and the intake valve closing timing IVC is compressed from the intake bottom dead center BDC (compressed from the intake stroke). It is changed to the third predetermined value IVC3 which is close to the bottom dead center when moving to the stroke). By eliminating the valve overlap, the residual gas in the combustion chamber 5 is suppressed, and the intake valve closing timing IVC is set to a third predetermined value IVC3 that is close to the intake bottom dead center BDC, thereby reducing the compression temperature of the gas in the combustion chamber 5. Thus, even if the throttle valve opening TVO is set to the third predetermined value TVO3 and the throttle valve 23 is throttled, the combustion state is improved.

As described above, by using the VEL mechanism 26 and the VTC mechanism 27 to improve the combustion state during the fuel cut delay period, the throttle valve opening during the fuel cut delay period is correspondingly changed to the VEL mechanism 26 and the VTC mechanism 27. Therefore, the fuel cut delay period is shortened by an amount corresponding to a decrease in the throttle valve opening.
Since the fuel cut delay period is a period during which fuel injection is continued, if the fuel cut delay period is shortened, the amount of fuel injection can be reduced to improve fuel efficiency.

  When the fuel cut recovery condition is satisfied at t2, the fuel cut flag is reset from 1 to zero, and the valve timing (open timing IVO and closing timing IVC) of the intake valve 15 is changed according to the operating condition immediately after the fuel cut recovery. . That is, the intake valve opening timing IVO is returned to the second predetermined value IVO2, and the intake valve closing timing IVC is returned to the second predetermined value IVC2. The throttle valve opening TVO is returned to the second predetermined value TVO2 corresponding to the accelerator opening at that time. Note that these second predetermined values (IVO2, IVC2, TVO2) do not coincide with actual control values.

  In the hybrid vehicle 50, the motor 51 is used as a generator (generator) when the vehicle is decelerated, and the kinetic energy of the vehicle is converted into electric energy and collected in the battery 77. If the engine 1 and the motor 51 are in a direct connection state during the regeneration control of the motor 51, the regeneration efficiency is deteriorated by the pumping loss of the engine 1. Therefore, there is a conventional apparatus that performs cylinder deactivation in order to reduce the pumping loss of the engine during regenerative control. However, with the method of reducing the pumping loss by performing cylinder deactivation, a shock due to torque fluctuation occurs when shifting from cylinder operation to cylinder deactivation when the vehicle decelerates, and from cylinder deactivation when recovering from a fuel cut There is also a problem that a shock that is caused by torque fluctuation occurs when shifting to cylinder operation. In addition, there is a method of controlling the throttle valve 23 to the open side when the vehicle is decelerated and reducing the pumping loss to improve the regeneration efficiency. In this method, a large amount of fresh air (air) is generated when the vehicle decelerates, 10 and the storage oxygen amount becomes full, and there is a possibility that the generation of NOx immediately after the fuel cut recovery cannot be suppressed.

  Therefore, the engine controller 31 (valve timing changing means) uses the VEL mechanism 26 and the VTC mechanism 27 (variable valve timing mechanism) to reduce the pumping loss during the fuel cut after stopping the fuel cut delay period (when the fuel supply is stopped). The valve timing of the intake valve 15 is changed in the decreasing direction.

  This will be specifically described with reference to FIG. For the purpose of reducing the pumping loss, the valve timing of the intake valve 15 is changed from t1 using the VEL mechanism 26 and the VTC mechanism 27. That is, the intake valve closing timing IVC is changed to the fourth predetermined value IVC4 that is farther from the intake bottom dead center BDC, so that fresh air (air) does not enter the combustion chamber 5 (FIG. 3 FIG. 3). (See the solid line on the third row). Although the piston 6 rises from the intake bottom dead center BDC to compress the fresh air in the combustion chamber 5, if the intake valve 15 is open at this time, the fresh air in the combustion chamber 5 flows back to the intake port 4. Therefore, the amount of fresh air remaining in the combustion chamber 5 after the intake valve 15 is closed is reduced. In the embodiment shown in FIG. 3, the intake valve closing timing IVC is set to the retard side away from the intake bottom dead center BDC, but may be changed to the advance side away from the intake bottom dead center BDC. .

  On the other hand, the intake valve opening timing IVO is changed to a fourth predetermined value IVO4 that is more advanced than the exhaust valve closing timing EVC so that valve overlap occurs. As a result, the fresh air flowing into the combustion chamber 5 once blows off to the exhaust port, but then blows back to the intake port 4, and this also keeps the fresh air remaining in the combustion chamber 5 after the intake valve 15 is closed. The amount of. In the embodiment, the exhaust valve closing timing EVC is on the immediate advance side of the intake top dead center TDC and is a fixed value.

  Thus, since the amount of fresh air remaining in the combustion chamber 5 after the intake valve 15 is closed is reduced, the force when the piston 6 compresses fresh air in the combustion chamber 5 is the combustion chamber 2. Smaller than before the amount of fresh air remaining in the interior is reduced. That is, the pumping loss which is an unnecessary work caused by the vertical movement of the piston 6 is reduced, and the work corresponding to the reduced pumping loss is directed to the regeneration control of the motor 51, so that the regeneration efficiency is increased. In addition, in the conventional device that reduces the pumping loss by cylinder deactivation, torque fluctuation is generated at the time of transition from cylinder operation to cylinder deactivation when the vehicle is decelerated, or vice versa. In this embodiment, the pumping loss is reduced by changing the valve timing of the intake valve 15, so that torque variation does not occur unlike the conventional apparatus. Further, even during re-acceleration after the vehicle is decelerated, it is possible to shift to a partial load or fully-open load state only by changing the valve timing, so that it is not necessary to generate torque fluctuation.

  This control performed by the engine controller 31 will be described in detail based on the flowchart of FIG. FIG. 4 is for performing control at the time of fuel cut, and is executed at regular time intervals (for example, every 10 msec). Note that the control before the fuel cut and the control from the fuel cut recovery are not directly related to the present invention and are not omitted.

  In step 1, the fuel cut flag is checked. The fuel cut flag is a flag that switches from zero to 1 when the fuel cut condition is satisfied. When the fuel cut flag = 0, the current process is terminated.

  When the fuel cut flag = 1 in step 1, the process proceeds to step 2 to compare the timer value with the fuel cut delay period (actually the fuel cut delay time). The fuel cut delay period is, for example, a constant value and is determined in advance by conformance. The timer is started when the fuel cut flag is switched from zero to one. When the timer value has not passed the fuel cut delay period, it is determined that it is within the fuel cut delay period, and the process proceeds to steps 3-6. Even during fuel cut, after the timer value has passed the fuel cut delay period, the routine proceeds to steps 7-10.

  Steps 3 to 6 and 10 are the same as the current state control performed in the fuel cut delay period in the engine including the VEL mechanism 26 and the VTC mechanism 27. That is, when the timer value has not passed the fuel cut delay period, the intake valve opening timing IVO is set to the third predetermined value IVO3 and the intake valve closing timing IVC is set to the third predetermined value IVC3 in steps 3, 4 and 5. The valve opening TVO is set (changed) to the third predetermined value TVO3. In step 6, fuel injection is performed (fuel injection permission flag = 1).

  The third predetermined value TVO3 is for closing the throttle valve 23 and reducing the amount of air flowing into the combustion chamber 5. The third predetermined value IVO3 is for changing the opening timing IVO of the intake valve 15 so that the valve overlap is eliminated. The third predetermined value IVC3 is for changing the closing timing IVC of the intake valve 15 to the vicinity of the intake bottom dead center BDC.

  On the other hand, Steps 7 and 8 are newly added portions according to the present invention, and Steps 9 and 10 are the same portions as the current control. That is, when the timer value is in the remaining fuel cut after the fuel cut delay period has elapsed, the intake valve opening timing IVO is set to the fourth predetermined value IVO4 and the intake valve closing timing IVC is set to the fourth predetermined value in steps 7, 8, and 9. Set (change) to IVC4, and maintain the throttle valve opening TVO at the third predetermined value TVO3. In step 10, fuel injection is stopped (fuel injection permission flag = 0).

  The fourth predetermined value IVC4 is for changing the closing timing IVC of the intake valve 15 to a position away from the intake bottom dead center BDC toward the retarded angle side. The fourth predetermined value IVO4 is for changing the opening timing IVO of the intake valve 15 to an advance side with respect to the closing timing EVC of the exhaust valve 16 so that valve overlap occurs.

  In a valve timing control flow (not shown), control signals are generated so as to obtain the intake valve opening timing IVO and the intake valve closing timing IVC set (changed) in this way, and are sent to the VEL mechanism 26 and the VTC mechanism 27. . The throttle valve opening TVO thus set is converted into a control signal and then sent to the throttle motor 24. In the fuel injection execution flow (not shown), the fuel injection is not performed if the fuel injection permission flag = 0 at the fuel injection timing, and the fuel injection is performed when the fuel injection permission flag = 1.

  Here, the effect of this embodiment is demonstrated.

  According to the present embodiment (the invention described in claim 1), the engine of the hybrid vehicle 50 that includes the engine 1 having the fuel injection valve 21 and the motor 51 as drive sources and performs regenerative control of the motor 51 during vehicle deceleration. The control device includes a VEL mechanism 26 and a VTC mechanism 27 (variable valve timing mechanism), determines whether or not a fuel cut condition is satisfied, and supplies fuel from the fuel injection valve 21 after the fuel cut condition is satisfied. The valve timing of the intake valve 15 is changed in the direction in which the pumping loss is reduced by using the VEL mechanism 26 and the VTC mechanism 27 while the fuel supply is stopped (see steps 1, 7, 8, and 10 in FIG. 4). ), Pumping loss can be reduced without performing cylinder deactivation as in the case of conventional devices. Thereby improving the regeneration efficiency of the regenerative control of the only motor 51.

  According to the present embodiment (the invention described in claim 2), the valve timing changing means (engine controller 31) changes the closing timing IVC of the intake valve 15 to a position separated from the intake bottom dead center BDC toward the retard side. Therefore, the piston 6 rises from the intake bottom dead center BDC. However, if the intake valve 15 is open at this time, fresh air in the combustion chamber 5 flows back to the intake port 4. Accordingly, the amount of fresh air remaining in the combustion chamber 5 after the intake valve 15 is closed is reduced, and the pumping loss can be reduced as compared with the case where the intake valve closing timing IVC is near the intake bottom dead center BDC.

  According to the present embodiment (the invention according to claim 3), the valve timing changing means sets the opening timing IVO of the intake valve 15 to an advance side with respect to the closing timing of the exhaust valve 16 so that valve overlap occurs. Since the change is made (see step 7 in FIG. 4), the fresh air flowing into the combustion chamber 5 once blows off to the exhaust port, but then blows back to the intake port 4, thereby burning after the intake valve 15 is closed. The amount of fresh air remaining in the chamber 5 is reduced, and the pumping loss can be reduced as compared with the case where no valve overlap occurs.

  According to the present embodiment (the invention described in claim 5), the fuel cut condition is satisfied in the fuel cut delay period (delay period) in which the exhaust passage 8 includes the three-way catalysts 9 and 10 and the fuel injection is continued. From the timing (see t0 in FIG. 4) to the timing (see t1 in FIG. 4) when the amount of air flowing into the combustion chamber 5 decreases after the throttle valve 23 is throttled at the timing when the fuel cut condition is satisfied. The amount of storage oxygen in the original catalysts 9 and 10 does not become full, so that NOx can be reduced.

  According to the present embodiment (the invention described in claim 6), the fuel and air from the fuel injection valve 21 are used by the VEL mechanism 26 and the VTC mechanism 27 in the fuel cut delay period in which the fuel injection is continued. Therefore, the valve timing of the intake valve 15 is changed in a direction in which the combustion state of the air-fuel mixture formed in the combustion chamber 5 is improved (see steps 3 and 4 in FIG. 4). Since it can be further reduced, the fuel cut delay period (that is, the period during which fuel injection is continued) can be shortened, and the fuel efficiency is improved.

  According to the present embodiment (the invention described in claim 7), changing the valve timing in the fuel cut delay period means that the opening timing IVO of the intake valve 15 is set from the exhaust valve closing timing EVC so that the valve overlap is eliminated. Is also changed to the retard side, and the closing timing IVC of the intake valve 15 is changed to the vicinity of the intake bottom dead center BDC (see steps 3 and 4 in FIG. 4). Residual gas in the chamber 5 is suppressed, and the intake valve 15 closes in the vicinity of the intake bottom dead center, so that the compression temperature of the gas in the combustion chamber 5 rises, thereby improving the combustion state.

  5 and 6 show the second embodiment, which replaces FIGS. 3 and 4 of the first embodiment. The difference from the first embodiment is only the part that increases the throttle valve opening TVO to the fourth predetermined value TVO4 (opens the throttle valve 23) during the fuel cut after the fuel cut delay period has elapsed (FIG. 5). 5 Solid line at the fourth stage, see step 11 in FIG.

  In FIG. 5, at the timing of t1 when the fuel cut delay period ends, unlike the first embodiment, when the throttle valve opening TVO is changed to the fourth predetermined value TVO4 and the throttle valve 23 is opened by that amount, The intake pipe pressure approaches the atmospheric pressure as much as the throttle valve 23 is opened, and the pumping loss can be reduced by the change in pressure. However, until the timing of t1 in FIG. 5, the throttle valve opening TVO is changed to a third predetermined value TVO3 close to zero, the throttle valve 23 is closed, and fuel injection is continued, thereby continuing the fuel injection. When the throttle valve 23 is opened at t1 even though the oxygen storage amount is not filled, the pumping loss is reduced, but fresh air (air) newly flows to the three-way catalysts 9, 10. There is a possibility that the oxygen storage amount of the three-way catalysts 9 and 10 becomes full. For this reason, when the charge amount of the battery 77 is equal to or greater than the specified value (the charge amount is sufficient), the exhaust performance is prioritized and the throttle valve opening TVO is close to zero in the period from t1 to t2 as in the first embodiment. The throttle valve opening TVO is set to the fourth throttle valve opening TVO in the period from t1 to t2 only when the charge amount of the battery 77 is less than the specified value (the charge amount is insufficient). It can be considered that the throttle valve 23 is opened by changing to the predetermined value TVO4. Therefore, when the throttle valve 23 is opened in the period from t1 to t2 as in the second embodiment, it is necessary to balance the improvement of the regeneration efficiency and the exhaust performance.

  According to the second embodiment (the invention described in claim 8), when the valve timing changing means changes the valve timing during the fuel cut after the fuel cut delay period has elapsed, the throttle valve 23 is opened and the intake pipe pressure is changed. (See steps 1, 2 and 11 in FIG. 6), the pumping loss is reduced by the amount that the intake pipe pressure approaches the atmospheric pressure, and the regeneration efficiency during the regeneration control of the motor 51 is improved. be able to.

  In the embodiment, the case where the hybrid vehicle is a one-motor, two-clutch hybrid vehicle has been described. However, the present invention is not limited to this case.

1 Engine body 21 Fuel injection valve (fuel supply means)
31 Engine controller (valve timing changing means)
26 VEL mechanism (variable valve timing mechanism)
27 VTC mechanism (variable valve timing mechanism)
50 Hybrid vehicle 51 Motor

Claims (8)

In an engine control apparatus for a hybrid vehicle that includes an engine having a fuel supply means and a motor as a drive source, and performs regeneration control of the motor when the vehicle decelerates.
A variable valve timing mechanism that can variably adjust the valve timing of the intake valve;
Fuel cut condition determining means for determining whether or not a fuel cut condition is satisfied;
Fuel supply stop means for stopping fuel supply from the fuel supply means after a fuel cut condition is satisfied;
An engine control device for a hybrid vehicle, comprising: valve timing changing means for changing the valve timing of the intake valve in a direction in which pumping loss is reduced using the variable valve timing mechanism while the fuel supply is stopped.   2. The hybrid vehicle engine control apparatus according to claim 1, wherein the valve timing changing means changes the closing timing of the intake valve to a position separated from an intake bottom dead center.   2. The hybrid vehicle engine according to claim 1, wherein the valve timing changing means changes the opening timing of the intake valve to an advance side relative to the closing timing of the exhaust valve so that valve overlap occurs. 3. Control device.   2. The hybrid vehicle engine control device according to claim 1, wherein the fuel cut condition is satisfied after a predetermined delay period elapses from a timing at which the fuel cut condition is satisfied. A three-way catalyst is provided in the exhaust passage,
The delay period is from the timing when the fuel cut condition is satisfied to the timing when the amount of air flowing into the combustion chamber is reduced after the throttle valve is throttled at the timing when the fuel cut condition is satisfied. 4. An engine control device for a hybrid vehicle according to 4.   6. The hybrid vehicle engine control device according to claim 5, wherein the valve timing of the intake valve is changed in a direction in which the combustion state is improved by using the variable valve timing mechanism during the delay period.   Changing the valve timing in the delay period changes the opening timing of the intake valve to a more retarded side than the closing timing EVC of the exhaust valve so that valve overlap does not occur, and sets the closing timing of the intake valve. The hybrid vehicle engine control device according to claim 6, wherein the engine control device is changed to a position close to an intake bottom dead center.   The hybrid vehicle engine control device according to claim 1, wherein when the valve timing changing means changes the valve timing, the throttle valve is opened so that the intake pipe pressure approaches the atmospheric pressure.

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