JP2007162664A - Valve operation angle variable control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suitably inhibit increase of oil consumption quantity while improving fuel economy by variable control of operation angle of an intake valve. <P>SOLUTION: An electronic control device for a valve operation angle variable control device reads operation information of the engine (step 110) and calculates target operation angle of the intake valve based on the operation information (step 120) in variable control of the operation angle of the intake valve. Then, an actuator is controlled to adjust actual operation angle to target operation angle (step 160). In addition to such a base process flow, it is judged whether the engine is in deceleration fuel cut or not (step 140), target operation angle calculated in the step 120 is expanded (step 150) when it is in deceleration fuel cut, and the value is used for the control of the actuator (step 160). The intake valve is kept open from start to end of intake stroke by expansion of operation angle and period during which a piston drops under an intake valve close condition does not occur in intake stroke. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable valve operating angle control device for an internal combustion engine that variably controls an operating angle of an intake valve according to an engine operating state.

Conventionally, as a device applied to an internal combustion engine, a valve working angle variable control device that variably controls a working angle of an engine valve such as an intake / exhaust valve in accordance with an engine operating state has been proposed (for example, see Patent Document 1). ). In an internal combustion engine employing such a variable valve operating angle control device, the amount of air taken into the combustion chamber can be reduced by reducing the operating angle of the intake valve. In this case, since the pumping loss can be reduced by reducing the intake air amount by reducing the throttle valve, it is possible to operate at a lower output and improve the fuel consumption.
JP 2001-263015 A

  By the way, in-vehicle internal combustion engines, so-called fuel cut during deceleration is performed in which fuel supply to the internal combustion engine is stopped when the vehicle is decelerated to improve fuel efficiency. During fuel cut during deceleration, the slot valve is throttled to increase engine braking, so the negative pressure (pressure lower than the atmospheric pressure) generated downstream of the throttle valve in the intake passage is high. Even when the intake valve is open, the cylinder has a negative pressure.

  Here, if the operating angle of the intake valve (shown by a thick arrow in FIG. 8) is reduced as shown in FIGS. 7 and 8 during the fuel cut during deceleration, a relatively long period T1 during the intake stroke. , T2, the piston is lowered with the intake valve closed. During these periods T1 and T2, as described above, the cylinder that is in a negative pressure state when the intake valve is opened is further depressurized, so that the cylinder negative pressure temporarily increases significantly.

  When the in-cylinder negative pressure becomes extremely high, oil on the cylinder wall surface is sucked into the combustion chamber through the piston ring. The oil sucked into the combustion chamber is consumed by combustion after the fuel cut at the time of deceleration recovery. Therefore, in an internal combustion engine that reduces the intake air amount by reducing the operating angle of the intake valve, the oil consumption tends to increase.

  The present invention has been made in view of such circumstances, and the problem to be solved is to suitably suppress an increase in oil consumption while improving fuel efficiency by variable control of the working angle of the intake valve. Another object of the present invention is to provide a variable valve operating angle control device for an internal combustion engine.

In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, in the variable valve operating angle control device for an internal combustion engine that variably controls the operating angle of the intake valve according to the engine operating state, the operating angle during fuel cut during deceleration is not Compared to enlargement.

  According to the above configuration, when the fuel cut during deceleration is not being performed, the amount of air taken into the combustion chamber is reduced by reducing the operating angle of the intake valve. For this reason, in a general internal combustion engine, i.e., a cylinder in which a piston is reciprocally accommodated and a throttle valve is provided in an intake passage connected to the cylinder, the throttle valve is throttled. As a result, the pumping loss is smaller than when reducing the intake air amount. Driving at a lower output is possible, and fuel consumption can be improved.

  Also, if the throttle valve is throttled to increase engine brake and the fuel pressure during deceleration when the negative pressure downstream of the throttle valve in the intake passage is increased is reduced, the operating angle of the intake valve is reduced as described above. A period in which the piston descends with the intake valve closed is generated. During this period, the pressure is reduced more than when the piston descends with the intake valve open. In this regard, according to the first aspect of the present invention, the operating angle is expanded during fuel cut during deceleration as compared to when it is not. Due to this enlargement, the period during which the piston descends with the intake valve closed is shortened or eliminated, and the depressurization due to the descending of the piston is suppressed, and the phenomenon that the in-cylinder negative pressure is temporarily significantly increased is less likely to occur. As a result, the phenomenon that the oil on the cylinder wall surface is sucked into the combustion chamber through the piston ring and the phenomenon that the oil is consumed by combustion after the fuel cut at the time of deceleration is restored is suppressed, and the oil consumption is preferably increased. It is suppressed.

  According to a second aspect of the present invention, in the first aspect of the invention, the expansion of the operating angle during the fuel cut during deceleration is performed so that the intake valve opens from the start to the end of the intake stroke. Suppose there is.

  According to the above configuration, the intake valve is opened from the start to the end of the intake stroke due to the expansion of the operating angle during fuel cut during deceleration. For this reason, there is no period in which the piston descends while the intake valve is closed during the intake stroke, and decompression due to the piston descending during the same period is reliably suppressed.

  Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. As shown in FIG. 1, a vehicle is equipped with a cylinder injection type gasoline engine (hereinafter simply referred to as an engine) 11 as an internal combustion engine. The engine 11 has a plurality of cylinders 12 in which pistons 13 are accommodated so as to be able to reciprocate. Each piston 13 is connected to a crankshaft 16 that is an output shaft of the engine 11 via a connecting rod 15. The reciprocating motion of each piston 13 is converted into a rotational motion by the connecting rod 15 and then transmitted to the crankshaft 16.

  An intake passage 22 having a throttle valve 18, a surge tank 19, an intake manifold 21, etc. is connected to the combustion chamber 17 for each cylinder 12. Air outside the engine 11 passes through each part of the intake passage 22 and is taken into the combustion chamber 17. The throttle valve 18 is rotatably provided in the intake passage 22 and is drivingly connected to an actuator 23 made of an electric motor or the like. The actuator 23 operates in response to a depression operation of the accelerator pedal 24 by the driver, and rotates the throttle valve 18. The amount of air flowing through the intake passage 22 (intake air amount) varies according to the rotation angle (throttle opening) of the throttle valve 18.

  The combustion chamber 17 is connected to an exhaust passage 26 having an exhaust manifold 25, a catalytic converter (not shown), and the like. Combustion gas generated in the combustion chamber 17 passes through each part of the exhaust passage 26 and is discharged to the outside of the engine 11.

  The engine 11 is provided with an intake valve 27 for opening and closing a connection portion of the intake passage 22 with the combustion chamber 17 and an exhaust valve 28 for opening and closing a connection portion of the exhaust passage 26 with the combustion chamber 17 for each cylinder 12. Yes. These intake / exhaust valves 27 and 28 are always in a direction (valve closing direction, substantially upward in FIG. 1) in which communication between the intake / exhaust passages 22 and 26 and the combustion chamber 17 is blocked by a valve spring (not shown). It is energized. An intake camshaft 31 having an intake cam 31A is provided substantially above the intake valve 27, and an exhaust camshaft 32 having an exhaust cam 32A is provided substantially above the exhaust valve 28. These intake / exhaust camshafts 31 and 32 rotate when the rotation of the crankshaft 16 is transmitted. With this rotation, the intake / exhaust camshafts 31, 32 push down the intake / exhaust valves 27, 28 against the valve spring. By this depression, the intake / exhaust passages 22 and 26 are in communication with the combustion chamber 17 (opened state). In this way, the intake / exhaust valves 27, 28 are periodically opened and closed as the intake / exhaust camshafts 31, 32 rotate.

  An electromagnetic fuel injection valve 33 is attached to the engine 11 for each cylinder 12. Each fuel injection valve 33 is controlled to open and close, thereby directly injecting and supplying high-pressure fuel to the corresponding combustion chamber 17. The fuel injected from the fuel injection valve 33 is mixed with the air in the combustion chamber 17 and becomes an air-fuel mixture.

  A spark plug 34 is attached to the engine 11 for each cylinder 12. Each spark plug 34 operates based on an ignition signal from the igniter 35. A high voltage output from the ignition coil 36 is applied to the spark plug 34. The air-fuel mixture is ignited by the spark discharge of the spark plug 34 and burned. The piston 13 is reciprocated by the high-temperature and high-pressure combustion gas generated at this time, the crankshaft 16 is rotated, and the driving force (output torque) of the engine 11 is obtained.

  This driving force is adjusted according to the depression operation of the accelerator pedal 24 by the driver. That is, according to the depression operation of the accelerator pedal 24, the throttle valve 18 is driven by the actuator 23 to adjust the throttle opening, and the intake air amount into the combustion chamber 17 changes. Corresponding to this change, the fuel injection amount from the fuel injection valve 33 is controlled, and the amount of air-fuel mixture filled in the combustion chamber 17 is changed to adjust the output of the engine 11.

  By the way, the engine 11 has a series of four strokes (cycles) of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while the crankshaft 16 rotates twice (720 ° CA rotation) and the piston 13 reciprocates twice. This is a so-called four-cycle engine. The intake stroke and the expansion stroke are performed when the piston 13 is lowered, and the compression stroke and the exhaust stroke are performed when the piston 13 is raised. By these strokes, the state in each cylinder 12 changes roughly as follows.

  In the intake stroke, the exhaust valve 28 is closed and the intake valve 27 is opened, and air is sucked into the combustion chamber 17 due to a decrease in pressure in the combustion chamber 17 as the piston 13 descends. In the compression stroke, the intake valve 27 is closed in addition to the exhaust valve 28. For this reason, the pressure in the combustion chamber 17 increases as the piston 13 rises. In the expansion stroke, ignition by the spark plug 34 is performed with both the intake and exhaust valves 27 and 28 closed, and the mixture of the intake air and the fuel injected from the fuel injection valve 33 is ignited and burned. The The downward force accompanying the combustion pushes down the piston 13, and a rotational force is applied to the crankshaft 16 through the connecting rod 15. In the exhaust stroke, the exhaust valve 28 is opened. For this reason, the exhaust gas generated in the combustion chamber 17 is discharged to the exhaust passage 26 as the piston 13 rises (see FIG. 6).

The engine 11 is provided with a variable valve timing mechanism 41 and a variable operating angle mechanism 42 as variable valve mechanisms that change the valve characteristics of the intake valve 27.
The variable valve timing mechanism 41 changes the relative rotational phase of the intake camshaft 31 with respect to the crankshaft 16, thereby maintaining a constant valve opening period of the intake valve 27 as shown by a solid line and a two-dot chain line in FIG. In this state, the valve opening timing and the valve closing timing of the intake valve 27 are both advanced or retarded.

  The working angle variable mechanism 42 is a mechanism that continuously varies the working angle of the intake valve 27. Here, as shown in FIG. 3, the operating angle is an angle range from the start of opening of the intake valve 27 to the closing of the rotation of the intake cam 31A (expressed by a crank angle in FIG. 3). . In the present embodiment, the maximum lift amount of the intake valve 27 is continuously changed by the operating angle variable mechanism 42. The maximum lift amount is a movement amount when the intake valve 27 moves (lifts) to the lowest position. These working angles and the maximum lift amount are changed in synchronization with each other by the working angle variable mechanism 42. For example, the smaller the working angle, the smaller the maximum lift amount. As the operating angle decreases, the opening timing and closing timing of the intake valve 27 approach each other, and the valve opening period becomes shorter.

  For example, as shown in FIG. 1, the operating angle variable mechanism 42 includes an intermediate drive mechanism 43 provided for each cylinder 12, and a control shaft 44 and an actuator 46 that are common to all the intermediate drive mechanisms 43 ( JP, 2001-263015, A) can be used. The actuator 46 includes, for example, an electric motor and a power transmission mechanism that converts the rotation of the electric motor into a linear motion and transmits the linear motion to the control shaft 44. And if an electric motor rotates by electricity supply, a power transmission mechanism will act | operate in connection with it and the control shaft 44 will be displaced to an axial direction.

  Each mediation drive mechanism 43 is provided between the intake camshaft 31 and the intake valve 27 and includes an input arm 47 and an output arm 48. A power transmission slider 49 is interposed between the control shaft 44 and the input / output arms 47 and 48 so as to be rotatable and movable in the axial direction. The slider 49 and the input / output arms 47 and 48 are meshed with each other by a helical spline.

  When the intake camshaft 31 rotates, the input cam 47 swings up and down around the control shaft 44 by the intake cam 31A. This swing is transmitted to the output arm 48 via the slider 49, and the output arm 48 swings up and down. The swinging output arm 48 drives the intake valve 27 to open it. As the valve is opened, air is sucked into the combustion chamber 17 from the intake passage 22.

  Further, when the control shaft 44 is moved in the axial direction by the actuator 46, the slider 49 rotates while being displaced in the same direction, and the input arm 47 and the output arm 48 in the swinging direction of the input / output arms 47, 48. And the relative phase difference is changed. With this change, the valve characteristics (working angle and maximum lift amount) of each intake valve 27 change continuously. When the relative phase difference is small, both the operating angle and the maximum lift amount are small, and the intake air amount per cylinder 12 is small. As the relative phase difference increases, both the operating angle and the maximum lift amount increase and the intake air amount increases.

  Further, various sensors for detecting the state of each part are attached to the vehicle. As these sensors, for example, a crank angle sensor 51, a rotation angle sensor 52, an air flow meter 53, a throttle sensor 54, an accelerator sensor 55, and the like are used.

  The crank angle sensor 51 generates a pulse signal every time the crankshaft 16 rotates by a certain angle. This signal is used for calculation of a crank angle that is a rotation angle of the crankshaft 16 and an engine rotation speed that is a rotation speed of the crankshaft 16 per unit time. The rotation angle sensor 52 detects the rotation angle of the electric motor in the actuator 46 in order to detect the valve characteristics (working angle and maximum lift amount) of the intake valve 27. The air flow meter 53 detects the amount of air flowing through the intake passage 22 (intake air amount), the throttle sensor 54 detects the throttle opening, and the accelerator sensor 55 detects the depression amount of the accelerator pedal 24 by the driver.

  The vehicle is provided with an electronic control device 61 that controls each part such as the engine 11 based on the various signals. The electronic control unit 61 is configured around a microcomputer, and a central processing unit (CPU) performs arithmetic processing according to a control program, initial data, a control map, etc. stored in a read-only memory (ROM). Various controls are executed based on the calculation result. The calculation result by the CPU is temporarily stored in a random access memory (RAM).

Examples of the control performed by the electronic control device 61 include fuel injection control of the engine 11, ignition timing control, throttle opening control, working angle control of the intake valve 27, and the like.
Here, in the fuel injection control, the fuel amount required for the operation of the engine 11 is calculated from the signals of various sensors that detect the state of the engine 11, and the fuel injection amount so that the air-fuel ratio of the air-fuel mixture becomes an optimum value. Is controlled. The injection amount is determined by the energization time of the fuel injection valve 33, that is, the valve opening time.

  In this fuel injection control, the fuel injection amount for setting the air-fuel ratio of the air-fuel mixture to a predetermined value (for example, the theoretical air-fuel ratio) is determined based on the operating state of the engine 11 such as the engine speed and the engine load. (Injection time). The engine load is obtained based on, for example, the intake air amount of the engine 11 or parameters related thereto (throttle opening, accelerator depression amount, etc.). Then, the obtained basic injection amount is corrected based on the signal from each sensor, so that the air-fuel ratio becomes a value corresponding to the operating state of the engine 11.

  One of the control modes of the fuel injection control is a so-called fuel cut in which the output of an injection signal to the fuel injection valve 33 is stopped and the fuel injection valve 33 is closed to stop the fuel injection. This fuel cut includes a fuel cut during deceleration performed for the purpose of improving driving fuel efficiency, purifying exhaust gas, and the like. In this control, the fuel cut start condition and return condition for deceleration are set as follows, for example.

The fuel cut start condition for deceleration is that both (A1) and (A2) are met.
(A1): The accelerator is off, that is, the accelerator depression amount is “0”.
(A2) The engine speed must be equal to or higher than the fuel cut speed.

The return condition from the fuel cut during deceleration is that either of the following (B1) or (B2) is satisfied.
(B1): The accelerator must not be off.
(B2): The engine speed must be lower than the return speed. The return rotational speed is set to a value lower than the fuel cut rotational speed.

  When the fuel cut start condition is satisfied, the fuel injection amount is reduced to “0” from the normal accelerator-off value. Further, when the return condition is satisfied after the start condition is satisfied, the fuel injection amount is increased to the value at the time of normal accelerator off.

  In the ignition timing control, the ignition timing of the air-fuel mixture in each combustion chamber 17 is controlled by each spark plug 34 according to the operating state of the engine 11. In this ignition timing control, the state of the engine 11 is detected based on signals from various sensors, and the optimal ignition timing is calculated for the state of the engine 11 at that time. When the crank angle calculated based on the signal from the crank angle sensor 51 reaches the ignition timing, an ignition signal is output to the igniter 35. The igniter 35 interrupts the primary current of the ignition coil 36 based on the ignition signal. Due to this interruption, a high voltage is generated in the secondary coil of the ignition coil 36 and the ignition plug 34 is ignited. The air-fuel mixture is ignited and burned by spark discharge accompanying ignition of the spark plug 34.

  In the throttle opening control, basically, the actuator 23 is driven and controlled so that the throttle valve 18 is opened as the accelerator depression amount indicating the driver's output request to the engine 11 increases. Here, as the throttle opening increases, the intake air amount of the engine 11 increases, and the fuel injection amount increases accordingly, so that the amount of air-fuel mixture filled in the combustion chamber 17 increases and the engine output increases. Becomes big. Therefore, an engine output corresponding to the driver's output request for the engine 11 is obtained.

  Further, in the throttle opening control, during the fuel cut during deceleration in the fuel injection control, in order to increase the resistance to intake and increase the action of the engine brake, the actuator 23 is set so that the throttle valve 18 is closed. Drive control is performed.

  Further, in the operation angle control of the intake valve 27, the target operation angle is calculated based on parameters relating to the operating state of the engine 11, such as the engine speed and the engine load. On the other hand, based on the rotation angle detected by the rotation angle sensor 52, the actual operating angle of the intake valve 27 corresponding to the rotation angle is calculated. The energization of the actuator 46 is controlled so that the actual operating angle becomes the target operating angle. By such energization control, the operating angle (maximum lift amount) of the intake valve 27 is adjusted to a value suitable for the operating state of the engine 11.

  For example, the operating angle of the intake valve 27 is increased in order to make it easier to secure the intake air amount of the engine 11 as the engine load increases with the engine rotational speed being constant. This is because as the engine load increases, a larger engine output is required, and the amount of intake air required to obtain the output increases.

  Further, as the engine load decreases, the required intake air amount decreases, so that the operating angle of the intake valve 27 is reduced and the intake air amount is reduced. It is not necessary to control the throttle valve 18 to the closed side to reduce the intake air amount, and the throttle valve 18 can be held at a predetermined opening on the open side. Therefore, problems associated with controlling the throttle valve 18 to the closed side as described above, such as an increase in pumping loss and a decrease in fuel consumption, are suppressed.

  By the way, as described above, the throttle valve 18 is controlled to be closed during the fuel cut during deceleration in the fuel injection control, so that the pressure of the intake passage 22 is low (the intake pipe negative pressure is high), and the intake valve 27 is Even in the open state, the cylinder has negative pressure. Under such circumstances, if the operating angle of the intake valve 27 is small, a period in which the piston 13 descends during the intake stroke with the intake valve 27 closed (see T1 and T2 in FIGS. 7 and 8), When the intake valve 27 is opened, the inside of the cylinder that is in a negative pressure state is further depressurized, and the in-cylinder negative pressure may be significantly increased temporarily. Therefore, in the present embodiment, processing for suppressing the occurrence of such a state where the in-cylinder negative pressure is extremely high is performed in the operation angle control.

Next, the processing content of the operating angle control of the intake valve 27 by the electronic control device 61 will be described with reference to the flowchart of FIG.
In this control, first, in step 110, the electronic control unit 61 reads engine operation information necessary for calculating the target operating angle, for example, the engine rotation speed and the engine load described above. Further, the actual operating angle of the intake valve 27 necessary for controlling the actuator 46 is read. This actual working angle is calculated separately based on the rotation angle detected by the rotation angle sensor 52.

  Next, in step 120, a target operating angle is calculated based on the engine operation information. For this calculation, for example, it is possible to refer to a map created by previously obtaining the relationship between the engine rotational speed and the engine load and the target operating angle through experiments or the like.

  Subsequently, in step 130, it is determined whether or not the target operating angle in step 120 is smaller than a predetermined value α. Here, the predetermined value α is a value corresponding to the crank angle (180 ° CA) required for the intake stroke or a value slightly smaller than that. If the determination condition of step 130 is satisfied, for example, as indicated by a two-dot chain line in FIG. 5, the intake valve 27 starts to open at a timing later than the start timing (TDC) of the intake stroke, and the intake stroke The valve is closed earlier than the end time (BDC).

  If the determination condition of step 130 is satisfied (target operating angle: small), it is determined in step 140 whether or not a fuel cut during deceleration is performed in the fuel injection control by another routine.

  If the determination condition of step 140 is satisfied (during fuel cut during deceleration), the target operating angle (see the two-dot chain line in FIG. 5) calculated in step 120 in step 150 is the solid line in FIG. Enlarge as shown. The target operating angle is expanded so that the intake valve 27 opens from the start time to the end time of the intake stroke. Thus, the target operating angle is expanded only when the determination conditions of steps 130 and 140 are both satisfied. Then, after the processing of step 150, the process proceeds to the next step 160.

  On the other hand, if at least one of the determination condition of step 130 and the determination condition of step 140 is not satisfied, the process proceeds to step 160 without passing through the process of step 150. In this case, the target operating angle calculated in step 120 is directly used as a control command value (target value) for the actuator 46 without being enlarged.

  In step 160, the actuator is set so that the actual operating angle of the intake valve 27 becomes the target operating angle calculated in step 120 (when the processing of step 150 is not performed) or the target operating angle expanded in step 150. The energization to 46 is controlled. Then, after the processing of step 160, a series of processing of the working angle control routine is ended.

  According to the operating angle control routine, when the fuel cut is not being performed during deceleration, the target operating angle of the intake valve 27 is reduced as shown by a two-dot chain line in FIG. The amount is reduced. As a result of this reduction, the pumping loss is reduced as compared with the case where the throttle valve 18 is throttled to reduce the intake air amount by controlling the throttle opening to the closed side.

  Further, if the operating angle of the intake valve 27 is reduced during the deceleration fuel cut as well, a period in which the piston 13 descends with the intake valve 27 closed is generated. During this period, the pressure is reduced more than when the piston 13 is lowered while the intake valve 27 is open. In this regard, in the present embodiment, the operating angle is enlarged during fuel cut during deceleration compared to when it is not (see the solid line in FIG. 5 and the thick arrow in FIG. 6). Due to this enlargement, the intake valve 27 is opened during the intake stroke in which the piston 13 descends. Therefore, during the fuel cut during deceleration, the throttle valve 18 is throttled to increase the engine brake and the intake pipe negative pressure increases, but during the intake stroke, there is a period during which the piston 13 descends while the intake valve 27 is closed. Does not occur. There is no pressure reduction due to the lowering of the piston 13 with the intake valve 27 closed, and the occurrence of a phenomenon in which the in-cylinder negative pressure becomes significantly high temporarily is suppressed.

According to the embodiment described in detail above, the following effects can be obtained.
(1) When the fuel is not cut during deceleration, the amount of air taken into the combustion chamber 17 is reduced by reducing the operating angle of the intake valve 27. Therefore, by controlling the throttle opening to the closed side, the pumping loss can be reduced as compared with the case where the throttle valve 18 is throttled to reduce the intake air amount. Driving at a lower output becomes possible, and fuel consumption can be improved.

  (2) In order to increase the engine brake, the operating angle of the intake valve 27 is increased during the fuel cut at the time of deceleration when the throttle valve 18 is throttled and the intake pipe negative pressure is increased as compared with the case where it is not. I have to. By doing so, it is possible to suppress the pressure reduction caused by the lowering of the piston 13 while the intake valve 27 is closed, and to make it difficult to cause a phenomenon that the in-cylinder negative pressure becomes extremely high temporarily. As a result, the phenomenon that the oil on the cylinder wall surface is sucked into the combustion chamber 17 via the piston ring 14 and the phenomenon that the oil is consumed by combustion after the fuel cut at the time of deceleration is restored is suppressed, and the oil consumption is increased. Can be suitably suppressed.

  (3) The intake valve 27 is opened from the start to the end of the intake stroke by expanding the target operating angle during fuel cut during deceleration. For this reason, there is no longer a period in which the piston 13 descends while the intake valve 27 is closed during the intake stroke, and pressure reduction due to the piston 13 descending during the same period is reliably suppressed, and the effect of the above (2) is further enhanced. It can be certain.

Note that the present invention can be embodied in another embodiment described below.
The expansion mode of the target operating angle may be changed as appropriate on the condition that the operating angle of the intake valve 27 is expanded more than when the fuel is cut during deceleration. For example, when the target operating angle is increased, the intake valve 27 may be opened at a timing before the start of the intake stroke and closed at a timing after the end of the intake stroke.

In the operating angle control routine of FIG. 4, the processing of step 130 may be omitted, and the target operating angle may be expanded uniformly during the fuel cut during deceleration compared to the case where it is not.
The variable valve operating angle control device may change only the operating angle among the valve characteristics (maximum lift amount and operating angle) of the intake valve 27 as the valve characteristics.

The present invention can be applied to an internal combustion engine in which the operating angle of the exhaust valve 28 is changed in addition to the intake valve 27.
-As a working angle variable mechanism, you may use a different type from what was used in the said embodiment. For example, the intake cam of the intake camshaft is a three-dimensional cam whose profile changes in the axial direction, and the intake camshaft is displaced in the axial direction by an actuator so that the operating angle changes according to the engine operating state. A thing may be used as a working angle variable mechanism. The point is that the operating angle of the intake valve can be variably controlled according to the engine operating state.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic which shows the structure about one Embodiment which actualized the valve working angle variable control apparatus of this invention. The characteristic view which shows the change aspect of the valve timing of an intake valve by a valve timing variable mechanism. The characteristic view which shows the change aspect of the working angle of the intake valve by a working angle variable mechanism. The flowchart which shows the procedure which controls the working angle of an intake valve. The characteristic view which shows the relationship between a crank angle and the working angle of an intake valve. Diagram showing intake and exhaust valve opening period. The characteristic view which shows the relationship between the crank angle and the working angle of an intake valve in background art. The diagram which shows the valve opening period of the intake / exhaust valve in background art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Gasoline engine (internal combustion engine), 27 ... Intake valve, 42 ... Working angle variable mechanism, 61 ... Electronic control unit.

Claims (2)

In a valve working angle variable control device for an internal combustion engine that variably controls a working angle of an intake valve according to an engine operating state,
A variable valve operating angle control device for an internal combustion engine, wherein the operating angle during fuel cut during deceleration is increased as compared to when it is not. 2. The variable valve operation angle control device for an internal combustion engine according to claim 1, wherein the expansion of the operating angle during the fuel cut during deceleration is performed so that the intake valve opens from the start to the end of the intake stroke.

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