JP4525562B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to an internal combustion engine control apparatus, and more particularly, to an internal combustion engine suitable as an apparatus for controlling an internal combustion engine having a variable valve mechanism that continuously varies the operating angle and / or lift amount of an intake valve. The present invention relates to a control device.

  Conventionally, in a spark ignition internal combustion engine such as a gasoline engine, it is usual to adjust the output at the time of partial load by restricting the intake air by a throttle valve. When the intake air is throttled by the throttle valve, the pumping loss (throttle loss) increases. One cause of the inferior fuel consumption of vehicles equipped with gasoline engines compared to vehicles equipped with diesel engines is an increase in pumping loss at partial load.

  On the other hand, in recent years, an internal combustion engine having a variable valve mechanism that continuously varies the working angle (operating angle) and lift amount of an intake valve has begun to appear. According to this internal combustion engine, output adjustment at the time of partial load can be performed by making the operating angle and lift amount of the intake valve smaller than at the time of full load. For this reason, according to this internal combustion engine, pumping loss can be reduced and fuel consumption can be improved.

  If it is assumed that the variable valve mechanism has failed, the operating angle and lift amount of the intake valve cannot be changed, and the operating angle and lift amount at the time of failure may be fixed. When such a situation occurs in a state of a small operating angle and lift amount, for example, in an idle operation state, only a small amount of air equivalent to the idle can be sucked into the cylinder thereafter. For this reason, in this case, the vehicle cannot travel.

  Even if the variable valve mechanism breaks down, it is not desirable that the vehicle immediately become unable to travel, and it is possible to self-travel without disturbing the flow of traffic to a safe place or repair shop, that is, evacuation traveling Preferably it is possible.

  In Japanese Patent Laid-Open No. 2004-84521, in an internal combustion engine provided with a working angle changing means for making the working angle of the intake valve variable and a timing changing means for changing the opening / closing timing, those variable valve mechanisms have failed. In such a case, an apparatus for performing control for enabling retreat travel has been proposed. According to this device, the retreat travel performance when the variable valve mechanism fails can be ensured as much as possible by the control logic.

JP 2004-84521 A

  However, when the above-described situation occurs, it is difficult to ensure sufficient evacuation traveling performance by a method that relies only on the control logic as in the above-described prior art. On the other hand, an engine mounted on a commercial vehicle is required to be able to evacuate reliably even when the variable valve mechanism fails, from the viewpoint of fail-safe.

  For this reason, conventionally, when a variable valve mechanism that continuously varies the working angle and lift amount of the intake valve is employed in an engine of a commercial vehicle, the working angle and lift amount are minimized in terms of mechanism or control. Even in such a case, the air must be designed so that the amount of air that can be retreated can be sucked into the cylinder. In this case, in an operation region where the load is smaller than that state, the output must be adjusted by restricting the intake air with the throttle valve as in the conventional case, resulting in a large pumping loss. For this reason, the effect of improving the fuel efficiency cannot be obtained sufficiently.

  The present invention has been made to solve the above-described problems, and can adjust the output at the time of partial load by continuously varying the operating angle and / or the lift amount of the intake valve to the low load region. Another object of the present invention is to provide a control device for an internal combustion engine that can reliably exert an output that allows the vehicle to retreat even when a variable valve mechanism fails.

In order to achieve the above object, a first invention is a control device for an internal combustion engine,
A variable valve mechanism capable of driving the intake valve with a continuously variable working angle and / or lift amount;
A fixed valve mechanism capable of driving the intake valve with a predetermined operating angle and lift amount capable of securing an intake air amount capable of generating an output necessary for retreat travel;
A switching mechanism that switches between a state in which the intake valve follows the variable valve mechanism and a state in which the intake valve follows the fixed valve mechanism;
An abnormality detecting means for detecting an abnormality of the variable valve mechanism;
Fail-safe means for setting the intake valve to follow the fixed valve mechanism when an abnormality of the variable valve mechanism is detected;
It is characterized by providing.

The second invention is the first invention, wherein
When the intake valve is driven by the fixed valve mechanism by the fail-safe means, the operating range limiting means limits the operating range of the internal combustion engine to a range lower than a predetermined engine speed and load. Is further provided.

The third invention is the first or second invention, wherein
When the intake valve is brought into a state of being driven by the fixed valve mechanism by the fail-safe means, it further comprises a travelable speed estimating means for estimating a travelable speed in the subsequent retreat travel.

According to a fourth invention, in any one of the first to third inventions,
When the operation of the internal combustion engine is stopped after the intake valve is brought into a state of being driven by the fixed valve mechanism by the fail safe means, the intake valve is driven by the fixed valve mechanism even at restart. As described above, the apparatus further comprises a maintaining means for maintaining the state of the switching mechanism.

According to a fifth invention, in any one of the first to fourth inventions,
Fuel cut means for performing fuel cut during deceleration of the internal combustion engine;
During the execution of the fuel cut, prohibiting means for prohibiting the fail safe means from functioning;
Is further provided.

According to a sixth invention, in any one of the first to fifth inventions,
The internal combustion engine includes a plurality of intake valves per cylinder,
The variable valve mechanism is intended to drive all of the plurality of intake valves,
The fixed valve mechanism is for driving a part of the plurality of intake valves,
The switching mechanism can be switched to a state in which some of the intake valves are driven by the fixed valve mechanism and other intake valves are driven by the variable valve mechanism.

According to a seventh invention, in any one of the first to sixth inventions,
The variable valve mechanism has a variable-side swing member that swings in synchronization with the rotation of the cam with an amplitude that changes according to the operating angle and / or the lift amount,
The fixed valve mechanism is disposed adjacent to the variable-side swing member, and has a fixed-side swing member that swings at a predetermined amplitude in synchronization with rotation of the cam.
The switching mechanism includes an advanceable / retractable connection pin installed on one of the variable-side swing member and the fixed-side swing member;
A pin hole formed on the other of the variable-side rocking member and the fixed-side rocking member and into which the connecting pin can be inserted;
The entrance portion of the pin hole is formed with a guide surface for guiding the connection pin so that insertion is possible even in a state where the center positions of the connection pin and the pin hole do not coincide with each other. To do.

  According to the first aspect, when an abnormality occurs in the variable valve mechanism that drives the intake valve, the intake valve can be driven by the fixed valve mechanism. The fixed valve mechanism drives the intake valve with an operating angle and a lift amount that can secure an intake air amount necessary for retreating. For this reason, according to the first aspect, even when the variable valve mechanism is out of order, it is possible to reliably retreat the vehicle. According to the first aspect of the present invention, the retraction travel performance when the variable valve mechanism fails can be ensured by the fixed valve mechanism, so that the minimum value of the operating angle and / or lift amount of the variable valve mechanism is retracted. There is no need to limit the travel performance to ensure the performance, and therefore the minimum value of the intake valve operating angle and / or lift amount can be made sufficiently small. For this reason, when the variable valve mechanism is normal, output adjustment during partial load by continuously varying the operating angle and / or lift amount of the intake valve can be performed including the low load region. Therefore, the pumping loss can be reduced to the maximum, and the fuel efficiency improvement effect by the variable valve mechanism can be utilized to the maximum.

  According to the second aspect of the present invention, it is possible to limit the operating range of the internal combustion engine to a range lower than the predetermined engine speed and load during retreat travel. For this reason, it is possible to avoid an excessive burden on the internal combustion engine during the retreat travel, and thus it is possible to reliably prevent further damage from the variable valve mechanism from progressing or expanding.

  According to the third invention, it is possible to estimate the travelable speed of the vehicle during the retreat travel. Then, by notifying the driver of the vehicle of the travelable speed, the driver can determine whether or not the destination can be reached by the scheduled time, and is not worried.

  According to the fourth aspect of the invention, the intake valve can be reliably driven by the fixed valve mechanism even at the time of restart when the operation of the internal combustion engine is stopped during the retreat travel. For this reason, a sufficient in-cylinder intake air amount can be ensured at the time of restart, and restart can be performed without failure.

  According to the fifth aspect of the present invention, it is possible to prevent the intake valve from following the fixed valve mechanism during the retreat travel and during the deceleration fuel cut. For this reason, it is possible to avoid a large amount of air from flowing through the exhaust purification catalyst during the deceleration fuel cut during the evacuation travel, and to suppress the deterioration of the exhaust purification catalyst.

  According to the sixth aspect of the invention, in an internal combustion engine having a plurality of intake valves per cylinder, some intake valves of the same cylinder are driven by a fixed valve mechanism, and other intake valves are driven by a variable valve device. By doing so, it is possible to make a difference in the operating angles and / or lift amounts of the plurality of intake valves. By setting it as this state, an overflow (swirl, tumble) can be effectively generated in the cylinder, and combustion can be improved.

  According to the seventh aspect of the invention, the center position of the connecting pin that can be moved forward and backward installed in one of the variable-side oscillating member and the fixed-side oscillating member does not coincide with the pin hole formed in the other of the two Even so, the connection pin can be reliably inserted into the pin hole by being guided by the guide surface. For this reason, even if the variable valve mechanism is fixed in an operating angle and / or lift amount of any size, switching by the switching mechanism can be performed reliably.

Embodiment 1 FIG.
[System configuration]
FIG. 1 is a diagram for explaining a system configuration according to the first embodiment of the present invention. The system of Embodiment 1 includes a spark ignition type internal combustion engine 1 mounted on a vehicle as a power source. The internal combustion engine 1 has a plurality of cylinders 2. FIG. 1 shows only one cylinder among a plurality of cylinders.

  The internal combustion engine 1 includes a piston 3 and a cylinder block 4 that houses the piston 3. The piston 3 is connected to the crankshaft 5 via a connecting rod. A crank angle sensor 6 is provided in the vicinity of the crankshaft 5. The crank angle sensor 6 is configured to detect the rotation angle of the crankshaft 5.

  A cylinder head 8 is assembled to the upper part of the cylinder block 4. The cylinder head 8 is provided with a spark plug 11 that ignites the air-fuel mixture in the combustion chamber 10.

  The cylinder head 8 includes an intake port 12 that communicates with the combustion chamber 10. Two intake valves, a first intake valve 14L and a second intake valve 14R, are provided per cylinder at the connection portion between the intake port 12 and the combustion chamber 10. The first intake valve 14L and the second intake valve 14R are driven by the intake camshaft 15, the variable valve mechanism 40, and the fixed valve mechanism 70. Details of the variable valve mechanism 40 and the fixed valve mechanism 70 will be described later.

  An intake passage 19 is connected to the intake port 12. In the vicinity of the intake port 12, an injector 20 that injects fuel into the intake port 12 is provided. A surge tank 21 is provided in the middle of the intake passage 19.

  A throttle valve 22 is provided upstream of the surge tank 21. The throttle valve 22 is an electronically controlled throttle that is driven by a throttle motor 23. The throttle valve 22 is driven based on the accelerator opening detected by the accelerator opening sensor 24. A throttle opening sensor 25 is provided in the vicinity of the throttle valve 22. The throttle opening sensor 25 is configured to detect the throttle opening. An air flow meter 26 is provided upstream of the throttle valve 22. The air flow meter 26 is configured to detect the intake air amount Ga. An air cleaner 27 is provided upstream of the air flow meter 26.

  The cylinder head 8 includes an exhaust port 28 that communicates with the combustion chamber 10. An exhaust valve 29 is provided at a connection portion between the exhaust port 28 and the combustion chamber 10. An exhaust passage 30 is connected to the exhaust port 28. The exhaust passage 30 is provided with an air-fuel ratio sensor 31 that detects an exhaust air-fuel ratio.

  The system according to the present embodiment includes an ECU (Electronic Control Unit) 60 as a control device. In addition to the ignition plug 11, the injector 20, and the throttle motor 23, a motor 46 for variably operating the variable valve mechanism 40, an OCV 84 (see FIG. 5) described later, and the like are connected to the output side of the ECU 60. On the input side of the ECU 60, there are a crank angle sensor 6, a throttle opening sensor 25, an accelerator opening sensor 24, an air flow meter 26, an air-fuel ratio sensor 31, a rotation angle sensor 47 for detecting the state of the variable valve mechanism 40, and the like. It is connected. The ECU 60 performs overall control of the internal combustion engine, such as fuel injection control, ignition timing control, and control for an intake valve operating mechanism described later, based on the output of each sensor.

[Outline of intake valve operating mechanism]
FIG. 2 is a perspective view for explaining the configuration of the intake valve operating mechanism in the present embodiment. As shown in FIG. 2, the internal combustion engine 1 has two intake valves, a first intake valve 14L and a second intake valve 14R, per cylinder. These intake valves open and close in synchronization with the rotation of the intake camshaft 15. The intake camshaft 15 is provided with an intake cam 16 belonging to the variable valve mechanism 40 and an intake cam 17 belonging to the fixed valve mechanism 70. The intake camshaft 15 is driven by the crankshaft 5 of the internal combustion engine 1 and rotates at half the speed of the crankshaft 5.

  The variable valve mechanism 40 can drive both the first intake valve 14L and the second intake valve 14R, and can continuously change the operating angle and the lift amount thereof. On the other hand, the fixed valve mechanism 70 drives only the second intake valve 14R and opens and closes it with a large operating angle and lift amount. Such an intake valve operating mechanism can selectively switch between a state in which the second intake valve 14R is driven by the variable valve operating mechanism 40 and a state in which the second intake valve 14 is driven by the fixed valve operating mechanism 70. It is configured.

  FIG. 3 is a view of the intake valve operating mechanism shown in FIG. 2 as viewed from a direction parallel to the intake camshaft 15. As shown in FIG. 3, the first intake valve 14 </ b> L is lifted when the end of the valve shaft (stem) 14 a is pressed against one end of the rocker arm 35. The other end of the rocker arm 35 is supported by the cylinder head 8 via a hydraulic lash adjuster 37. A rocker roller 36 is rotatably attached to an intermediate portion of the rocker arm 35. A similar rocker arm 35, rocker roller 36, and hydraulic lash adjuster 37 are also provided for the second intake valve 14R.

[Detailed Configuration of Variable Valve Mechanism 40]
Hereinafter, the configuration of the variable valve mechanism 40 will be described in detail. However, since the structure for the first intake valve 14L and the structure for the second intake valve 14R have a common part, the common part is the first intake valve. Only for 14L will be described.

  As shown in FIG. 3, the variable valve mechanism 40 has a control shaft 41 disposed in parallel with the intake camshaft 15. A control arm 42 is fixed to the control shaft 41 with bolts 43. A part of the control arm 42 protrudes in the radial direction of the control shaft 41. An intermediate arm 44 is attached to the protruding portion of the control arm 42 by a pin 45. The pin 45 is disposed at a position eccentric from the center of the control shaft 41. Therefore, the intermediate arm 44 is configured to swing around the pin 45. The control shaft 41, the control arm 42, and the intermediate arm 44 are shared by the first intake valve 14L and the second intake valve 14R.

  As shown in FIG. 2, a swing cam arm 50L for the first intake valve 14L and a swing cam arm 50R for the second intake valve 14R are supported on the control shaft 41 so as to be swingable. Since both of these structures and the surrounding structure are common, only the swing cam arm 50L side will be described.

  As shown in FIG. 3, the swing cam arm 50 </ b> L has a slide surface 50 a on the side facing the intake cam 16. The second roller 53 is in contact with the slide surface 50a. The slide surface 50a is formed in a curved surface such that the distance from the intake cam 16 gradually decreases as the second roller 53 moves from the distal end side of the swing cam arm 50L toward the axial center side of the control shaft 41. .

  A first roller 52 provided coaxially with the second roller 53 is in contact with the peripheral surface of the intake cam 16. Both the first roller 52 and the second roller 53 are rotatably supported by a connecting shaft 54 fixed to the tip of the intermediate arm 44. Since the intermediate arm 44 swings around the pin 45 as a fulcrum, the rollers 52 and 53 also swing along the slide surface 50 a and the peripheral surface of the intake cam 16 while maintaining a certain distance from the pin 45.

  Further, a swing cam surface 51 is formed on the swing cam arm 50L on the opposite side of the slide surface 50a. The rocker arm 35 described above is positioned below the swing cam arm 50L, and the rocker roller 36 is in contact with the swing cam surface 51. The rocking cam surface 51 has a non-operating surface (basic circle portion) 51a formed so that the distance from the rocking center of the rocking cam arm 50L is constant, and a position away from the non-operating surface 51a is the control shaft 41. The working surface 51b is formed so that the distance from the center of the axis is increased.

  A spring seat 50b is formed on the swing cam arm 50L. One end of a lost motion spring 38 is hung on the spring seat 50b. The other end of the lost motion spring 38 is fixed to the cylinder head 8. Due to the biasing force received from the lost motion spring 38, the slide surface 50a of the swing cam arm 50L is pressed against the second roller 53, and further, the first roller 52 is pressed against the intake cam 16. Thus, the first roller 52 and the second roller 53 are positioned in a state where they are sandwiched between the slide surface 50a and the peripheral surface of the intake cam 16 from both sides.

  According to the configuration of the variable valve mechanism 40 described above, the pressing force of the intake cam 16 is transmitted to the slide surface 50 a via the first roller 52 and the second roller 53 as the intake cam 16 rotates. As a result, when the contact point between the swing cam surface 51 and the rocker roller 56 extends from the non-operation surface 51a to the operation surface 51b, the rocker arm 35 is pushed down, and the first intake valve 14L and the second intake valve 14R are lifted ( Open).

  Further, according to the configuration of the variable valve mechanism 40, when the rotation angle of the control shaft 41 is changed, the position of the second roller 53 on the slide surface 50a changes, and the swing cam arms 50L and 50R during the lift operation are changed. The amplitude (oscillation range) changes. More specifically, when the control shaft 41 is rotated counterclockwise in FIG. 3, the position of the second roller 53 on the slide surface 50a moves to the tip side of the swing cam arms 50L, 50R. Then, the rotation angle of the swing cam arms 50L and 50R required until the rocker arm 35 actually starts to be pressed after the swing cam arms 50L and 50R start the swing operation by transmitting the pressing force of the intake cam 16 is transmitted. Increases as the control shaft 41 rotates counterclockwise in FIG. That is, the operating angle and lift amount of the first intake valve 14L and the second intake valve 14R can be reduced by rotating the control shaft 41 counterclockwise in FIG. Conversely, the operating angle and lift amount of the first intake valve 14L and the second intake valve 14R can be increased by rotating the control shaft 41 in the clockwise direction.

  The variable valve mechanism 40 includes a rotation drive mechanism that rotates the control shaft 41. The configuration of the rotation drive mechanism is not particularly limited, but in the present embodiment, a gear mechanism 48 including a worm wheel fixed to one end of the control shaft 41 and a worm gear meshing with the worm wheel, and the worm gear are rotationally driven. It is assumed that the motor 46 is configured. The motor 46 is operable in both forward and reverse directions in accordance with a command from the ECU 60. By operating the motor 46, the rotational position of the control shaft 41 can be adjusted, and the operating angle and the lift amount realized by the variable valve mechanism 40 can be changed.

  In the system of the present embodiment, a rotation angle sensor 47 is provided as a sensor that detects a working angle and a lift amount realized by the variable valve mechanism 40. The rotation angle sensor 47 is arranged so as to detect the rotation angle (rotation amount) of the rotation member of any one of the motor 46, the gear mechanism 48, and the control shaft 41. A signal generated by the rotation angle sensor 47 is input to the ECU 60. The ECU 60 can grasp the current operating angle and lift amount based on the signal from the rotation angle sensor 47.

[Detailed Configuration of Fixed Valve Mechanism 70]
Next, a detailed configuration of the fixed valve mechanism 70 will be described with reference to FIGS. 2 and 4. FIG. 4 is an exploded perspective view of a part of the variable valve mechanism 40 and the fixed valve mechanism 70.

  As shown in FIGS. 2 and 4, the fixed valve mechanism 70 includes an intake cam 17 and a large lift arm 71. The large lift arm 71 is arranged side by side with the swing cam arm 50 </ b> R and can swing about the control shaft 41. A roller 73 that contacts the peripheral surface of the intake cam 17 is rotatably supported by the large lift arm 71. The large lift arm 71 is biased by a lost motion spring (not shown) in such a direction that the roller 73 is pressed against the peripheral surface of the intake cam 17.

  The large lift arm 71 swings in synchronization with the rotation of the intake cam 17. The amplitude is the same as that of the swing cam arms 50L and 50R when the variable valve mechanism 40 is in the maximum operating angle and lift state.

[Configuration of Single Valve Switching Mechanism 72]
As shown in FIG. 4, a one-valve switching mechanism 72 is provided between the swing cam arm 50 </ b> R and the large lift arm 71 so that both can be connected and disconnected. The single valve switching mechanism 72 includes a connecting pin 74, a pin housing hole 75, a pin hole 76, a return spring 77, and a piston 78. When the one-valve switching mechanism 72 is in the connected state, the swing cam arm 50R is integrated with the large lift arm 71 and swings with an amplitude corresponding to the maximum operating angle and lift amount. For this reason, regardless of the state of the variable valve mechanism 40, the second intake valve 14R is driven with a large operating angle and lift amount.

  The large lift arm 71 is formed with a pin housing hole 75 that opens to the swing cam arm 50R side. A connecting pin 74 is fitted into the pin housing hole 75. The connecting pin 74 can protrude out of the pin storage hole 75 or can be retracted into the pin storage hole 75. The pin housing hole 75 is connected to a hydraulic system described later. The connection pin 74 can be pushed out from the pin housing hole 75 by increasing the oil pressure in the pin housing hole 75 by the hydraulic system.

  A pin hole 76 that opens to the large lift arm 71 side is formed in the swing cam arm 50R. The connecting pin 74 and the pin hole 76 are arranged equidistant from the center of the control shaft 41. Thus, when the swing cam arm 50R is positioned at a predetermined rotation angle with respect to the large lift arm 71, the position of the pin hole 76 and the position of the connecting pin 74 are matched. A return spring 77 and a piston 78 as a lifter are disposed in the pin hole 76 from the back side.

  FIG. 5 is a schematic diagram showing a configuration of a hydraulic system for operating the connecting pin 74. As shown in FIG. 5, an oil passage 81 is formed in the control shaft 41. The oil passage 81 is connected to the pin housing hole 75, the sliding clearance between the control shaft 41 and the large lift arm 71, and the sliding clearance between the control shaft 41 and the swing cam arm 50R. The oil passage 81 is supplied with hydraulic pressure from an oil pump 82 of the internal combustion engine 1. A discharge path 83 is connected in the middle of the oil path 81. The discharge path 83 is provided with an OCV (oil control valve) 84. The opening degree of the OCV 84 is duty controlled by the ECU 60. Further, an orifice 85 is provided downstream of the OCV 84 in the discharge path 83.

  When the OCV 84 is closed, the lubricating oil pressurized by the oil pump 82 is supplied to the sliding gap through the oil passage 81. A part of the lubricating oil flowing through the oil passage 81 is supplied to the pin housing hole 75. Therefore, the hydraulic pressure in the pin storage hole 75 can be increased. On the other hand, when the OCV 84 is opened, the lubricating oil is discharged from the discharge path 83. Thereby, the hydraulic pressure in the pin accommodation hole 75 can be lowered.

  In a state where the connecting pin 74 is not inserted into the pin hole 76, the swing cam arm 50R and the large lift arm 71 swing separately, but both are in the zero lift (intake valve closing period). Quiesce. During this stationary period, the connecting pin 74 can be inserted into the pin hole 76.

  The posture of the swing cam arm 50R at the time of zero lift varies depending on the position of the second roller 53 of the variable valve mechanism 40, that is, depending on the operating angle and the lift amount. Therefore, in order to insert the connecting pin 74 into the pin hole 76, first, the OCV 84 is closed to increase the hydraulic pressure in the pin housing hole 75, and then the positions of the connecting pin 74 and the pin hole 76 coincide with each other in the zero lift state. The rotational position of the control shaft 41 is adjusted so that a predetermined operating angle and lift amount are obtained. Then, at the moment when the positions of the connecting pin 74 and the pin hole 76 coincide with each other, the connecting pin 74 is pushed out and can be inserted into the pin hole 76. In this way, the swing cam arm 50R and the large lift arm 71 can be connected via the connecting pin 74.

  In order to release the above connection, the OCV 84 is opened and the hydraulic pressure in the pin housing hole 75 is lowered. Then, the return spring 77 pushes back the connecting pin 74 via the piston 78, so that the connecting pin 74 comes out of the pin hole 76. In this way, the connection between the swing cam arm 50R and the large lift arm 71 can be released.

[Both valves are lifted]
In a state where the swing cam arm 50R and the large lift arm 71 are not connected, both the first intake valve 14L and the second intake valve 14R are driven by the variable valve mechanism 40. This state is hereinafter referred to as a “both valve lift state”. FIG. 6A is a lift diagram of the first intake valve 14L and the second intake valve 14R in the lift state of both valves. As shown in this figure, in the lift state of both valves, the operating angle and the lift amount of the first intake valve 14L and the second intake valve 14R are equal to each other. Then, by rotating the control shaft 41, the working angle and the lift amount of both can be aligned and continuously changed.

  In the present embodiment, in the state in which the working angle and lift amount of the first intake valve 14L and the second intake valve 14R are minimized in the lift state of both valves and the like, the in-cylinder intake is performed even if the intake air is not throttled by the throttle valve 22. The variable valve mechanism 40 is designed so that the amount of air can be a slight amount of air equivalent to or close to idle operation. Therefore, in the internal combustion engine 1, the output adjustment at the time of partial load can be performed by continuously varying the operating angle and lift amount of the first intake valve 14L and the second intake valve 14R, including the low load region near the idle operation. Is possible. For this reason, pumping loss (throttle loss) can be reduced to the maximum, and fuel consumption can be greatly improved.

  In the lift state such as the double valve, the fixed valve mechanism 70 is idle without being involved in driving the intake valve.

[Single valve large lift state]
When the swing cam arm 50R and the large lift arm 71 are connected, the swing cam arm 50R is integrated with the large lift arm 71 that always swings with an amplitude corresponding to the maximum operating angle and lift amount. Therefore, the swing cam arm 50R has its slide surface 50a separated from the second roller 53, and swings with an amplitude corresponding to the maximum operating angle and lift amount. Therefore, in this state, the second intake valve 14R always moves with the maximum operating angle and lift amount regardless of the state of the variable valve mechanism 40. Such a state is hereinafter referred to as a “one-valve large lift state”.

  FIG. 6B is a lift diagram of the first intake valve 14L and the second intake valve 14R in the one-valve large lift state. The first intake valve 14R follows the variable valve mechanism 40 even in the one-valve large lift state, as in the double valve lift state. For this reason, when the control shaft 41 is rotated in the one-valve large lift state, as shown in FIG. 6B, the second intake valve 14R remains at the maximum operating angle and lift amount, as shown in FIG. The operating angle and the lift amount can be continuously changed.

  In this one-valve large lift state, the operating angle and lift amount of the first intake valve 14L can be made smaller than those of the second intake valve 14R. If it does in this way, air can be mainly made to flow in in a cylinder only through the 2nd intake valve 14R. For this reason, a strong overflow (swirl, tumble) can be formed in the cylinder. In the internal combustion engine 1, for example, in a medium load / medium rotation range, a single valve large lift state is formed, so that a strong overflow can be formed in the cylinder and the combustion speed can be increased to improve combustion.

[Map of working angle and lift amount]
FIG. 7 is a map of the operating angle and lift amount of the first intake valve 14L and the second intake valve 14R stored in the ECU 60. In this system, according to the map shown in FIG. 7, the operating angle and lift amount are adjusted by the variable valve mechanism 40, and the two-valve lift state and the one-valve large lift state are switched by the one-valve switching mechanism 72.

  The map shown in FIG. 7 is shown with the engine speed NE on the horizontal axis and the load on the vertical axis. In this system, the engine speed NE can be detected based on a signal from the crank angle sensor 6. Further, the load can be detected based on the accelerator opening or the intake air amount Ga detected by the air flow meter 26. Thereby, the ECU 60 can detect where the current operating state of the internal combustion engine 1 is in the map of FIG.

  In FIG. 7, several sets of two circles arranged side by side are drawn. Of the two circles in each group, the characters in the right circle indicate the operating angle and lift amount of the first intake valve 14L, and the characters in the left circle indicate the operating angle of the second intake valve 14R. And the lift amount.

  In this map, the high load region, the high rotation region, and the low load region are defined as regions that should be in a lift state such as both valves. This region is hereinafter referred to as “both valve lift region”. In the lift region of both valves and the like, adjustment of the in-cylinder intake air amount, that is, output adjustment of the internal combustion engine 1, is performed by continuously varying the operating angle and the lift amount of both the first intake valve 14L and the second intake valve 14R. It can be carried out.

  Further, in this map, the low / medium rotation / medium load region is defined as a region that should be in the single valve large lift state. This region is hereinafter referred to as a “single valve large lift region”. In the one-valve large lift region, adjustment of the in-cylinder intake air amount, that is, output adjustment of the internal combustion engine 1, can be performed by continuously varying the operating angle and lift amount of only the first intake valve 14L.

  When the operating state of the internal combustion engine 1 has shifted across the boundary between the double-valve lift region and the single-valve large lift region, the single-valve switching mechanism 72 operates to activate the double-valve lift state and the single-valve large size. Switching to the lift state is performed.

[Features of Embodiment 1]
If a mechanism that continuously varies the operating angle and lift amount of the intake valve, such as the variable valve mechanism 40, is employed, the vehicle can be retracted even if the variable valve mechanism 40 breaks down. It is required from the viewpoint of fail-safe that it is possible to make sure.

  The failure (abnormality) of the variable valve mechanism 40 in the present embodiment is due to damage or breakage of components (motor 46, gear mechanism 48, control shaft 41, arms, rollers, bearings, etc.) of the variable valve mechanism 40. The state in which the variable operation of the working angle and the lift amount cannot be performed smoothly or the variable operation cannot be performed.

  The above-described failure of the variable valve mechanism 40 is based on whether or not the actual operating angle and lift amount detected by the rotation angle sensor 47 follow the target operating angle and lift amount determined in the map of FIG. Can be detected. That is, if there is a discrepancy between the target operating angle and lift amount and the actual operating angle and lift amount, it can be determined that a failure has occurred in the variable valve mechanism 40.

  By the way, in the intake valve operating mechanism of the present embodiment, the second intake valve 14R can always be fixed at the maximum operating angle and lift amount by setting the single valve large lift state. If one of the second intake valves 14R has the maximum operating angle and lift amount, even if the operating angle and lift amount of the other first intake valve 14L are minimum, the cylinder more than half of the maximum intake amount It is possible to secure the amount of internal intake air. Therefore, in the one-valve large lift state, it is possible to exert an output (torque) that is at least half of the maximum output (maximum torque) of the internal combustion engine 1. And if the output of half of the maximum output can be exhibited, it is possible to perform the retreat travel.

  Therefore, in the present embodiment, when a failure of the variable valve mechanism 40 is detected, control for maintaining the one-valve large lift state is performed thereafter regardless of the map shown in FIG.

  According to this control, when a failure of the variable valve mechanism 40 is detected, if the valve is already in the one-valve large lift state, that is, if the connecting pin 74 is inserted into the pin hole 76, In order to continue this state, the OCV 84 is kept closed.

  On the other hand, when a failure of the variable valve mechanism 40 is detected, if the double valve is in a lift state, that is, if the connecting pin 74 is not inserted into the pin hole 76, the single valve large lift In order to shift to the state, it is necessary to insert the connecting pin 74 into the pin hole 76. As described above, in order to match the positions of the connecting pin 74 and the pin hole 76 in the zero lift state, the variable valve mechanism 40 needs to be in a state of a predetermined operating angle and lift amount. For this reason, when trying to insert the connecting pin 74 into the pin hole 76 after the failure of the variable valve mechanism 40, there is a high possibility that the positions of the connecting pin 74 and the pin hole 76 do not match. Since the variable valve mechanism 40 is out of order, it is difficult to match the positions of the two.

  Therefore, in the present embodiment, as will be described below, the connecting pin 74 can be connected even if the center positions of the connecting pin 74 and the pin hole 76 are not matched by devising the structure of the one-valve switching mechanism 72. Can be inserted into the pin hole 76.

  FIG. 8 is an enlarged cross-sectional view of the single valve switching mechanism 72. As shown in FIG. 8A, a guide surface 79 is formed at the entrance portion of the pin hole 76. In FIG. 8A, the center positions of the connecting pin 74 and the pin hole 76 are shifted. Even in such a case, the connecting pin 74 slides along the guide surface 79 in the process in which the connecting pin 74 is pushed out by hydraulic pressure, so that the connecting pin 74 moves in the center direction of the pin hole 76. To be guided to. As a result, as shown in FIG. 8B, the center positions of the connecting pin 74 and the pin hole 76 coincide with each other, and the connecting pin 74 can be inserted into the pin hole 76.

  Thus, in the present embodiment, the connecting pin 74 can be inserted into the pin hole 76 even if the variable valve mechanism 40 breaks down in any operating angle and lift state. Switching between the double valve lift state and the single valve large lift state can be performed.

[Specific Processing in Embodiment 1]
FIG. 9 is a flowchart of a routine executed by the ECU 60 in the present embodiment in order to realize the above function. Note that this routine is periodically executed at predetermined time intervals.

  According to the routine shown in FIG. 9, first, the operating angle and the lift amount realized by the variable valve mechanism 40 are detected (step S100). The actual working angle and lift amount can be calculated based on the signal from the rotation angle sensor 47 as described above.

  Next, it is determined whether or not the variable valve mechanism 40 is operating normally (step S110). Specifically, first, the actual operating angle and lift amount detected in step S100 are compared with the target operating angle and lift amount. It is assumed that the target operating angle and lift amount are calculated in other routines based on the current engine speed NE and load, according to the operating angle / lift amount map shown in FIG. When the deviation between the actual value of the operating angle and the lift amount and the target value is equal to or less than a predetermined determination value, it can be determined that the variable valve mechanism 40 is operating normally. In this case, this routine is finished as it is.

  On the other hand, when the deviation between the actual value of the working angle and the lift amount and the target value exceeds the predetermined determination value in step S110, an appropriate working angle and lift amount corresponding to the driving state are obtained. It can be determined that an abnormality (failure) has occurred in the variable valve mechanism 40. Therefore, in this case, the internal combustion engine 1 is subsequently operated in a one-valve large lift state in order to ensure sufficient retreat travel performance.

  Specifically, first, it is determined whether or not the current operation state is in the one-valve large lift region in the operating angle / lift amount map (step S120). If the current operating state is in the single valve large lift region, the single valve large lift state has already been realized. In this case, therefore, the OCV 84 is controlled so as to prohibit the follow- ing of the operating angle / lift amount map and maintain the one-valve large lift state as it is (step S121).

  On the other hand, in step S120, if the current operating state is in the double-valve lift region, since the double-valve lift state is currently in effect, a switching operation to the single-valve large lift state is performed (step S130). . Specifically, the OCV 84 is closed and the connecting pin 74 is pushed out by hydraulic pressure and inserted into the pin hole 76. In step S130, after the connection pin 74 is inserted, the OCV 84 is controlled so as not to follow the operating angle / lift amount map and to maintain the one-valve large lift state.

  If an abnormality occurs in the variable valve mechanism 40 by the above processing, the internal combustion engine 1 is always operated in the one-valve large lift state thereafter. For this reason, the in-cylinder intake air amount for generating the output necessary for the retreat travel can be reliably ensured. In this routine, the vehicle driver is then notified that an abnormality has occurred in the variable valve mechanism 40 (step S140). This notification is performed, for example, by turning on a warning lamp in the instrument panel. By notifying the driver of the abnormality of the variable valve mechanism 40, it is possible to alert the driver to consideration of traveling safety and engine protection during evacuation traveling, and prompt early confirmation and repair of the abnormal part.

  As described above, in the present embodiment, even when the variable valve mechanism 40 breaks down, the retreat travel performance can be reliably ensured. For this reason, the minimum value of the operating angle and lift amount of the intake valve is not limited in order to ensure the retreat travel performance, so that the fuel efficiency improvement effect by the variable valve mechanism 40 can be utilized to the maximum.

  That is, in the present embodiment, the output adjustment at the time of partial load is performed by continuously varying the operating angle and lift amount of the first intake valve 14L and the second intake valve 14R, including the low load region near the idle operation. Is possible. For this reason, pumping loss (throttle loss) can be reduced to the maximum, and fuel consumption can be greatly improved.

  Further, in the present embodiment, the one-valve large lift state is set during retreat travel, so that it is possible to exert an output that is approximately half of the maximum output or more. For this reason, evacuation traveling requiring a relatively large output can also be performed.

  In the present embodiment, the one-valve large lift state is used depending on the operation region even during normal operation. For this reason, since there is little difference between the engine operation state during retreat travel and the normal engine operation state during normal retreat, safe retreat travel without a sense of incongruity can be performed.

  In the first embodiment described above, the second intake valve 14R corresponds to the “intake valve” in the first invention, and the one-valve switching mechanism 72 corresponds to the “switching mechanism” in the first invention. ing. Further, when the ECU 60 executes the processes of steps S100 and S110, the “abnormality detection means” in the first invention executes the processes of steps S120, S122 and S130, thereby allowing the first invention. “Fail-safe means” in FIG.

  In the first embodiment described above, the swing cam arm 50R is the “variable swing member” in the seventh invention, and the large lift arm 71 is the “fixed swing member” in the seventh invention. , Respectively.

Embodiment 2. FIG.
Next, the second embodiment of the present invention will be described with reference to FIG. 10. The description will focus on the differences from the above-described embodiment, and the description of similar matters will be omitted or simplified. . The system of the present embodiment can be realized by causing the ECU 60 to execute a routine shown in FIG. 10 described later instead of the routine shown in FIG. 9 using the same hardware configuration as that of the first embodiment. .

[Features of Embodiment 2]
When the retreat travel is performed after the failure of the variable valve mechanism 40, it is preferable that the engine operation is performed so that the internal combustion engine 1 is not burdened as much as possible. Therefore, in the present embodiment, when performing retreat travel, the operating region of the internal combustion engine 1 is limited to a range lower than the engine speed NE and the load at the maximum output point in the one-valve large lift region during normal operation. It was decided to.

  Further, since the output of the internal combustion engine 1 is restricted during retreat travel, the travel speed of the vehicle is also restricted. From the standpoint of the driver, it is safer to know this in advance. Therefore, in the present embodiment, during the retreat travel, the travelable speed of the vehicle is estimated and this is notified to the driver.

[Specific Processing in Second Embodiment]
FIG. 10 is a flowchart of a routine executed by the ECU 60 in the present embodiment in order to realize the above function. In FIG. 10, the same steps as those shown in FIG. 9 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  According to the routine shown in FIG. 10, the same processing as in the first embodiment is performed from step S100 to S121 and S130. That is, when an abnormality of the variable valve mechanism 40 is detected, the valve is forcibly fixed to the one-valve large lift state thereafter.

  Next, control is started to limit the operating region of the internal combustion engine 1 to a range lower than the engine speed NE and the load at the maximum output point in the one-valve large lift region at normal time (step S150). Specifically, the fuel injection amount is limited so that the engine speed NE and the load of the internal combustion engine 1 do not exceed the above-mentioned limit range. As a result, the operating state of the internal combustion engine 1 is limited to the region of the engine speed NE and the load that are relatively low, so that the burden on the internal combustion engine 1 during retreat travel can be reduced. For this reason, it is possible to reliably prevent further damage and expansion of the variable valve mechanism 40 during retreat travel.

  Next, based on the signal from the air flow meter 26, the intake air amount in the current retreat travel state is detected (step S160). Based on the detected intake air amount, the travelable speed is estimated (step S170). Specifically, first, the current maximum output that can be generated under the detected intake air amount is calculated. The ECU 60 stores in advance the correlation between the intake air amount and the maximum output, and the current maximum output is calculated based on the correlation. The ECU 60 further stores in advance vehicle performance performance curve information. The travelable speed is calculated by comparing the travel performance curve information with the current maximum output. In this case, the travelable speed may be calculated for each road gradient.

  The information on the travelable speed calculated in step S170 is displayed on the display unit provided in the instrument panel, for example, together with the information indicating that the engine output is limited due to the failure of the variable valve device 40, The driver is notified (step S180). As a result, the driver can know the current travelable speed, and therefore can determine whether or not the destination can be reached by the scheduled time, without feeling uneasy.

  In the above-described second embodiment, the ECU 60 executes the process of step S150, so that the “operating region restriction means” in the second invention executes the processes of steps S160 and S170. The “travelable speed estimation means” in the third invention is realized.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to FIG. 11. The description will focus on the differences from the above-described embodiments, and the description of similar matters will be omitted or simplified. . The system of the present embodiment can be realized by causing the ECU 60 to execute a routine shown in FIG. 11 to be described later, instead of the routine shown in FIG. 9, using the same hardware configuration as that of the first embodiment. .

[Features of Embodiment 3]
Even when retreating after a failure of the variable valve mechanism 40, there may be a case where it is desired to park the engine and stop the internal combustion engine 1 once. In normal control, when the internal combustion engine 1 is stopped, that is, when the ignition switch is turned off, energization (duty signal application) to the OCV 84 is also stopped. When energization of the OCV 84 is stopped, the OCV 84 is in the open state which is the default state. As a result, the hydraulic pressure applied to the connection pin 74 is released, and the connection pin 74 is pushed back by the return spring 77.

  That is, when the internal combustion engine 1 is stopped during the retreat travel while being fixed in the single valve large lift state, the connection between the swing cam arm 50R and the large lift arm 71 is naturally released during the stop period, It will return to the lift state of both valves. In this case, if the variable valve mechanism 40 is fixed with a small operating angle and lift amount, when the internal combustion engine 1 is restarted, both the first intake valve 14L and the second intake valve 14R are small. The valve opens only at the operating angle and the lift amount. In such a case, the in-cylinder intake air amount may be too small to restart.

  Therefore, in the present embodiment, when the vehicle is evacuated, the control content of the ECU 60 is changed so that energization to the OCV 84 is continued even after the ignition switch is turned off. Thus, the single valve large lift state is maintained even when the internal combustion engine 1 is stopped, and the restart can be performed in the single valve large lift state. Therefore, at the time of restart, a sufficient amount of in-cylinder intake air can be ensured, and restart can be performed reliably. Even when the ignition switch is off, the ECU 60 normally continues to be energized from the battery, so it is possible to easily change the control contents as described above.

[Specific Processing in Embodiment 3]
FIG. 11 is a flowchart of a routine executed by the ECU 60 in the present embodiment in order to realize the above function. In FIG. 11, the same steps as those shown in FIG. 9 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  The routine shown in FIG. 11 is the same as the routine shown in FIG. 9 except that steps S111 and S112 are inserted between steps S110 and S120.

  That is, according to the routine shown in FIG. 11, when an abnormality of the variable valve mechanism 40 is detected in step S110, the actual operating angle and lift amount detected in step S100 are the values of both valves and the like. It is determined whether the operating angle and the lift amount can be restarted even when the lift state is reached (step S111). The ECU 60 stores in advance the minimum operating angle and lift amount that can be reliably restarted in the lift state of both valves and the like, and the determination in step S111 is performed by comparison with this.

  In step S111, if the operating angle and the lift amount are small and cannot be restarted in the double valve lift state, then the ECU 60 is controlled so that energization to the OCV 84 is continued even after the ignition switch is turned off. A part of the content is changed (step S112). After that, the processing from step S120 onward as in the first embodiment is executed.

  On the other hand, in step S111, if the operating angle and the lift amount are relatively large so that they can be restarted even in the double-valve lift state, the one-valve large lift state is changed to the double-valve lift state while the internal combustion engine 1 is stopped. Even if it returns, there is no problem with restart. Therefore, in this case, the process of step S112 is skipped and the process of step S120 and subsequent steps is executed.

  With the above processing, in the present embodiment, the internal combustion engine 1 can be reliably restarted even when the variable valve mechanism 40 is fixed with a small operating angle and lift amount during retreat travel. Can do.

  In the third embodiment described above, the “maintaining means” in the fourth aspect of the present invention is realized by the ECU 60 executing the process of step S112.

Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to FIG. 12. The description will focus on differences from the above-described embodiments, and the description of similar matters will be omitted or simplified. . The system of the present embodiment can be realized by causing the ECU 60 to execute a routine shown in FIG. 12 to be described later, instead of the routine shown in FIG. 9, using the same hardware configuration as that of the first embodiment. .

[Features of Embodiment 4]
When the internal combustion engine 1 is decelerated, fuel cut is usually performed for the purpose of saving fuel or the like. Therefore, when the internal combustion engine 1 is decelerated, air containing no fuel flows from the intake passage to the exhaust passage. On the other hand, the exhaust purification catalyst disposed in the exhaust passage of the internal combustion engine 1 has a characteristic that it easily deteriorates upon receiving a lean gas supply in a high temperature environment. For this reason, in order to suppress the deterioration of the catalyst during the fuel cut, it is desired to reduce the amount of air flowing when the internal combustion engine 1 is decelerated. Therefore, in the normal control, when the internal combustion engine 1 is decelerated, both valves are used in order to reduce the working air amount and the lift amount of both the first intake valve 14L and the second intake valve 14R to reduce the amount of circulating air. An equal lift state is selected.

  On the other hand, in the first to third embodiments described above, when the variable valve mechanism 40 fails, the internal combustion engine 1 is forcibly fixed to the one-valve large lift state regardless of the operating state of the internal combustion engine 1. The one-valve large lift state is maintained even during deceleration of 1. As a result, since the amount of air flowing through the catalyst during fuel cut increases, the catalyst tends to deteriorate.

  Therefore, in the present embodiment, even when an abnormality of the variable valve mechanism 40 is detected, control for forcibly fixing the internal combustion engine 1 to the one-valve large lift state is not performed while the internal combustion engine 1 is decelerating. The same control as that described above was performed, and after the deceleration of the internal combustion engine 1 was completed, the control for forcibly fixing the one-valve large lift state was performed.

[Specific Processing in Embodiment 4]
FIG. 12 is a flowchart of a routine executed by the ECU 60 in the present embodiment in order to realize the above function. In FIG. 12, the same steps as those shown in FIG. 9 are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  The routine shown in FIG. 11 is the same as the routine shown in FIG. 9 except that step S115 is inserted between steps S110 and S120.

  That is, according to the routine shown in FIG. 11, if an abnormality of the variable valve mechanism 40 is detected in step S110, it is next determined whether or not the internal combustion engine 1 is decelerating (step S115). ). Specifically, when the accelerator opening is zero and the engine speed NE is greater than or equal to a predetermined value, it is determined that the internal combustion engine 1 is decelerating. Alternatively, the deceleration of the internal combustion engine 1 may be determined using a vehicle speed change rate, a brake signal, or the like.

  If it is determined in step S115 that the internal combustion engine 1 is decelerating, this routine is terminated without performing the following processing. As a result, the intake valve operating mechanism is normally controlled according to the map shown in FIG. For this reason, since the amount of air flowing through the exhaust purification catalyst during the deceleration fuel cut can be made small compared to the one-valve large lift state, deterioration of the exhaust purification catalyst can be suppressed.

  When the deceleration of the internal combustion engine 1 is completed, it is recognized that the engine is not decelerating in step S115. In this case, the processing after step S120 similar to that in the first embodiment is thereafter executed. Thereby, it is forcibly fixed to the one-valve large lift state, and retreat travel performance can be secured.

  In the above-described fourth embodiment, the ECU 60 executes fuel cut when the internal combustion engine 1 is decelerated, so that the “fuel cut means” in the fifth aspect of the invention executes the process of step S115. The “prohibiting means” in the fifth aspect of the present invention is realized.

  In each of the above-described embodiments, the system having the function of switching between the double valve equal lift state and the single valve large lift state has been described. However, the present invention is limited to the system having such a switching function. It is not a thing. For example, the present invention provides a variable valve mechanism that continuously varies the operating angle and lift amount of two intake valves of the same cylinder during normal operation, and the amount of air that can be retracted when the variable valve mechanism is abnormal. The present invention can also be applied to a system including a fixed valve mechanism that can drive the two intake valves with a predetermined operating angle and lift amount that can be ensured. That is, the fixed valve mechanism in the present invention may not be used in normal times but may be used only when the variable valve mechanism is abnormal.

  In addition, the variable valve mechanism in the present invention is not limited to one in which both the operating angle and the lift amount of the intake valve are continuously variable, and one of the operating angle and the lift amount is continuously variable. You may do. In the present invention, the number of intake valves per cylinder is not limited to two, but may be one or three or more.

It is a figure for demonstrating the system configuration | structure of Embodiment 1 of this invention. It is a perspective view for demonstrating the structure of the intake valve operating mechanism in Embodiment 1 of this invention. FIG. 3 is a view of the intake valve operating mechanism shown in FIG. 2 as viewed from a direction parallel to the intake camshaft. It is a disassembled perspective view of a part of a variable valve mechanism and a fixed valve mechanism. It is the schematic which shows the structure of the hydraulic system for operating a connecting pin. It is a lift diagram of the 1st intake valve and the 2nd intake valve in a double valve equal lift state and a single valve large lift state. It is a map of the operating angle and lift amount of a 1st intake valve and a 2nd intake valve. It is sectional drawing which expands and shows a single valve switching mechanism. It is a flowchart of the routine performed in Embodiment 1 of the present invention. It is a flowchart of the routine performed in Embodiment 2 of this invention. It is a flowchart of the routine performed in Embodiment 3 of the present invention. It is a flowchart of the routine performed in Embodiment 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 6 Crank angle sensor 10 Combustion chamber 11 Spark plug 12 Intake port 14 Intake valve 14 Intake valve 15 Intake cam shaft 16, 17 Intake cam 19 Intake passage 20 Injector 22 Throttle valve 24 Accelerator opening sensor 25 Throttle opening sensor 26 Air flow meter 28 Exhaust port 30 Exhaust passage 35 Rocker arm 36 Rocker roller 37 Hydraulic lash adjuster 38 Lost motion spring 40 Variable valve mechanism 41 Control shaft 42 Control arm 44 Intermediate arm 45 Pin 46 Motor 47 Rotation angle sensor 48 Gear mechanism 50 Oscillating cam arm 52 First roller 53 Second roller 54 Connecting shaft 60 ECU
70 fixed valve mechanism 71 large lift arm 72 single valve switching mechanism 73 roller 74 connecting pin 75 pin receiving hole 76 pin hole 77 return spring 78 piston 79 guide surface 81 oil passage 82 oil pump 83 discharge passage 84 OCV
85 Orifice

Claims (6)

A variable valve mechanism capable of driving the intake valve with a continuously variable working angle and / or lift amount;
A fixed valve mechanism capable of driving the intake valve with a predetermined operating angle and lift amount capable of securing an intake air amount capable of generating an output necessary for retreat travel;
A switching mechanism that switches between a state in which the intake valve follows the variable valve mechanism and a state in which the intake valve follows the fixed valve mechanism;
An abnormality detecting means for detecting an abnormality of the variable valve mechanism;
Fail-safe means for setting the intake valve to follow the fixed valve mechanism when an abnormality of the variable valve mechanism is detected;
Fuel cut means for performing fuel cut during deceleration of the internal combustion engine;
During the execution of the fuel cut, prohibiting means for prohibiting the fail safe means from functioning;
A control device for an internal combustion engine, comprising:   When the intake valve is driven by the fixed valve mechanism by the fail-safe means, the operating range limiting means limits the operating range of the internal combustion engine to a range lower than a predetermined engine speed and load. The control apparatus for an internal combustion engine according to claim 1, further comprising:   The vehicle further comprises a travelable speed estimation unit that estimates a travelable speed in a subsequent retreat when the intake valve is driven by the fixed valve mechanism by the failsafe unit. 3. The control device for an internal combustion engine according to 1 or 2.   When the operation of the internal combustion engine is stopped after the intake valve is brought into a state of being driven by the fixed valve mechanism by the fail safe means, the intake valve is driven by the fixed valve mechanism even at restart. The control device for an internal combustion engine according to any one of claims 1 to 3, further comprising maintaining means for maintaining the state of the switching mechanism. The internal combustion engine includes a plurality of intake valves per cylinder,
The variable valve mechanism is intended to drive all of the plurality of intake valves,
The fixed valve mechanism is for driving a part of the plurality of intake valves,
The switching mechanism, according to claim 1 to 4 wherein a portion of the intake valves the following the fixed valve mechanism, and wherein the other intake valve is switchable to a state of driven in the variable valve device The control device for an internal combustion engine according to any one of the preceding claims. The variable valve mechanism has a variable-side swing member that swings in synchronization with the rotation of the cam with an amplitude that changes according to the operating angle and / or the lift amount,
The fixed valve mechanism is disposed adjacent to the variable-side swing member, and has a fixed-side swing member that swings at a predetermined amplitude in synchronization with rotation of the cam.
The switching mechanism includes an advanceable / retractable connection pin installed on one of the variable-side swing member and the fixed-side swing member;
A pin hole formed on the other of the variable-side rocking member and the fixed-side rocking member and into which the connecting pin can be inserted;
The entrance portion of the pin hole is formed with a guide surface for guiding the connection pin so that insertion is possible even in a state where the center positions of the connection pin and the pin hole do not coincide with each other. The control device for an internal combustion engine according to any one of claims 1 to 5 .

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