JP2009115058A - Internal combustion engine - Google Patents

Abstract

An object of the present invention is to promptly cope with an abnormality even when an abnormality occurs in a variable valve mechanism under conditions such as low rotation and low temperature at which a hydraulic system is difficult to operate.
An internal combustion engine includes a variable valve mechanism, a lash adjuster, and an adjuster movable mechanism. When the variable valve mechanism 68 is normal, the lash adjuster 80 is held at the normal position by the adjuster moving mechanism 82. When an abnormality of the variable valve mechanism 68 is detected, the lash adjuster 80 is held in the retracted position by the adjuster moving mechanism 82, and the protruding dimension T of the plunger 80B is made smaller than the normal state. Thus, when an abnormality is detected, the lift amount of the intake valve 38 can be reduced regardless of the engine speed, temperature state, etc. of the internal combustion engine 10. Therefore, interference between the intake valve 38 and the piston 16 can be reliably prevented.
[Selection] Figure 5

Description

  The present invention relates to an internal combustion engine equipped with a variable valve mechanism, and more particularly, to an internal combustion engine equipped with a safety mechanism for coping with abnormalities in the variable valve mechanism.

  2. Description of the Related Art Conventionally, as disclosed in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2005-220759), an internal combustion engine having a safety mechanism that copes with an abnormality of a variable valve mechanism is known. This type of conventional internal combustion engine includes a variable valve mechanism that variably sets the lift amount of an intake valve, for example. Further, the internal combustion engine of the prior art includes a hydraulic variable valve timing mechanism that advances and retards the phase of the intake valve.

  When the abnormality of the variable valve mechanism is detected, the phase of the intake valve is retarded by operating the variable valve timing mechanism. As a result, the phase of the intake valve moves away from the intake top dead center. For this reason, since the intake valve does not come into contact with the piston even when the intake valve is largely opened (lifted) due to abnormality of the variable valve mechanism, for example, these components can be protected.

JP 2005-220759 A

  In the above-described prior art, when an abnormality occurs in the variable valve mechanism, the phase of the intake valve is retarded by the hydraulic variable valve timing mechanism. In this case, the hydraulic variable valve timing mechanism needs to receive a sufficient hydraulic pressure supply from a hydraulic pump driven by the internal combustion engine.

  However, for example, when the engine speed is low, the output of the hydraulic pump also decreases according to the output of the internal combustion engine. Therefore, in this case, the hydraulic pressure supplied to the variable valve timing mechanism is insufficient, and the responsiveness of the mechanism is likely to deteriorate. In addition, when the temperature of the internal combustion engine is low, the viscosity of the hydraulic oil increases, and the fluidity of the hydraulic oil supplied to and discharged from the variable valve timing mechanism decreases. Also in this case, the responsiveness of the variable valve timing mechanism is lowered.

  For this reason, in the conventional technology, for example, if an abnormality occurs in the variable valve mechanism under conditions such as low rotation and low temperature, the variable valve timing mechanism cannot be operated quickly, and it is difficult to quickly deal with the abnormality. There is.

  The present invention has been made to solve the above-described problems, and even if an abnormality occurs in the variable valve mechanism under conditions such as low rotation and low temperature where the hydraulic system is difficult to operate, It is an object of the present invention to provide an internal combustion engine that can be dealt with promptly and can avoid chain failures of other components.

A first invention is a valve provided in a cylinder head of an internal combustion engine and driven to open and close by a cam;
A rocker arm in which one side in the length direction is in contact with the valve, and a rocker roller that receives the input of the cam is disposed in the middle portion in the length direction;
A lash adjuster having a plunger projecting from the cylinder head toward the rocker arm so as to be extendable and contractable, and supporting the other side of the rocker arm by the plunger to suppress the tappet clearance of the valve;
A variable valve mechanism that variably sets at least the lift amount among the opening and closing characteristics of the valve;
An abnormality detecting means for detecting an abnormality of the variable valve mechanism;
When an abnormality of the variable valve mechanism is detected by the abnormality detection means, an abnormal-time lift amount reduction means for reducing the protrusion amount of the plunger to reduce the lift amount of the valve;
It is characterized by providing.

2nd invention is equipped with the adjuster movable mechanism which can displace the whole said lash adjuster in the direction which approaches or separates from the said rocker arm,
The abnormal time lift amount reducing means is configured to displace the lash adjuster in a direction away from the rocker arm by the adjuster moving mechanism when an abnormality of the variable valve mechanism is detected.

According to a third invention, the adjuster movable mechanism is
An adjuster insertion hole that opens to the cylinder head at a position facing the rocker arm and into which the lash adjuster is slidably inserted,
A movable stopper that holds the lash adjuster on the opening side of the adjuster insertion hole when the abnormal-time lift amount reducing means is in an inoperative state;
Releasing means for releasing the movable stopper when the lift amount reducing means at the time of abnormality is activated, and allowing the lash adjuster to be displaced to the back side of the adjuster insertion hole;
It is set as the structure provided with.

A fourth invention comprises a variable valve timing mechanism for variably setting the phase of the valve;
An abnormal time retarding means for retarding the phase of the valve by the variable valve timing mechanism when an abnormality of the variable valve mechanism is detected by the abnormality detecting means;
It is set as the structure provided with.

  According to the first invention, the plunger of the lash adjuster supports the other end side of the rocker arm at a position corresponding to the protruding dimension. For this reason, when the protrusion dimension of the plunger decreases, the fulcrum of the rocker arm supported by the plunger (that is, the fulcrum when the rocker arm tilts) is displaced away from the cam side. As a result, when the valve is opened, the amount of tilting when the rocker arm is tilted to open the valve is smaller than the amount of pushing the rocker arm (rocker roller) from the cam side, and the lift amount of the valve is reduced. .

  Therefore, according to the abnormal lift amount reducing means, when the abnormality of the variable valve mechanism is detected, the protruding dimension of the plunger can be reduced, thereby forcibly reducing the lift amount of the valve. . The lift amount reducing operation can be performed promptly when an abnormality is detected regardless of the engine speed, temperature state, etc. of the internal combustion engine.

  That is, the abnormal lift amount reducing means only reduces the protrusion size of the lash adjuster, and therefore does not require a large hydraulic actuator such as a hydraulic variable valve timing mechanism. For this reason, even if the abnormal-time lift amount reducing means is activated during operation at a low rotation or low temperature, there is almost no response delay due to insufficient hydraulic pressure or increased oil viscosity. Therefore, the abnormal time lift amount reducing means can reliably avoid the valve from interfering with the piston even during operation at a low rotation or low temperature, and can prevent a chain failure of the valve or the piston.

  According to the second aspect, the adjuster movable mechanism can support the entire lash adjuster so as to be displaceable with respect to the rocker arm. For this reason, when an abnormality is detected, the protruding dimension of the plunger can be changed by the adjuster moving mechanism regardless of the expansion / contraction operation of the lash adjuster itself. Therefore, the protrusion dimension of the plunger can be reliably reduced to the target value at the time of abnormality. Further, for example, by simply adding an adjuster movable mechanism to a conventional lash adjuster, a mechanism for dealing with an abnormality can be easily realized, and the structure of the lash adjuster can be prevented from becoming complicated in order to prepare for an abnormality. .

  According to the third invention, when the variable valve mechanism is in a normal state, the lash adjuster can be held on the opening side of the adjuster insertion hole by the movable stopper. Then, the lash adjuster can be operated at the position on the opening side. Further, when the abnormality of the variable valve mechanism is detected, the operation of the movable stopper can be canceled by the releasing means. As a result, the abnormal lift amount reducing means can displace the lash adjuster to the back side of the adjuster insertion hole, and can reduce the protruding dimension of the plunger.

  According to the fourth aspect of the invention, the abnormal time retarding means can retard the phase of the valve by the variable valve timing mechanism when detecting an abnormality of the variable valve mechanism. As a result, the valve opening timing can be separated from the top dead center, and interference between the valve and the piston can be prevented. At the time of abnormality detection, if the responsiveness of the variable valve timing mechanism is good, the abnormal lift amount reducing means and the abnormal time retarding means can be operated together, which makes the valve and piston more reliable. Can be protected.

Embodiment 1 FIG.
[Configuration of Embodiment 1]
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. First, FIG. 1 shows an overall configuration diagram for explaining the system configuration of the first embodiment. The system of this embodiment includes a multi-cylinder internal combustion engine 10, for example. In the internal combustion engine 10, a cylinder head 14 is mounted on a cylinder block 12.

  A piston 16 is inserted into each cylinder of the internal combustion engine 10, and a combustion chamber 18 is defined between the piston 16 and the cylinder head 14. The piston 16 of each cylinder is connected to the crankshaft 20 of the internal combustion engine 10. The internal combustion engine 10 is provided with a rotation sensor 22 for detecting the rotation angle (crank angle) of the crankshaft 20.

  An intake passage 24 through which intake air of the internal combustion engine 10 flows toward the combustion chamber 18 and an exhaust passage 26 through which exhaust gas flows out from the combustion chamber 18 are connected to the combustion chamber 18 of each cylinder. An air flow meter 28 that detects the flow rate (intake air amount) of intake air flowing through the intake passage 24 is provided near the inlet of the intake passage 24. The intake passage 24 is provided with an electronically controlled throttle valve 30 that adjusts the amount of intake air. The throttle valve 30 is driven by a throttle motor 32 based on the accelerator opening.

  The cylinder head 14 includes a fuel injection valve 34 that injects fuel toward the combustion chamber 18 of each cylinder, an ignition plug 36 that ignites the air-fuel mixture in the combustion chamber 18, and an intake passage for the combustion chamber 18. An intake valve 38 for opening and closing 24 and an exhaust valve 40 for opening and closing the exhaust passage 26 with respect to the combustion chamber 18 are provided.

  These intake valve 38 and exhaust valve 40 are driven by valve trains 42 and 44, respectively. The structure of the valve trains 42 and 44 will be described in detail with reference to FIG. The intake side valve system 42 is provided with a lift amount sensor 46 for monitoring the lift amount of the intake valve 38 by an ECU 54 described later.

  The lift amount sensor 46 is constituted by, for example, generally known various non-contact sensors. The lift amount sensor 46 detects, for example, the position on the other end side of the rocker arm 60 (see FIG. 3 described later) as the lift amount of the intake valve 38 and outputs a detection signal to the ECU 54. The lift amount sensor 46 constitutes an abnormality detection means for detecting an abnormality in the valve system 42 on the intake side.

  Further, the internal combustion engine 10 includes a hydraulic VVT (Variable Valve Timing system) 48. The VVT 48 has a known configuration as disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-87769. The VVT 48 changes the rotational phase of an intake camshaft 64 (described later) with respect to the rotational angle of the crankshaft 20 in accordance with a control signal input from the ECU 54. Therefore, according to the VVT 48, the phase of the intake valve 38 can be advanced or retarded by a desired angle.

  The hydraulic VVT 48 is operable when a hydraulic pump 50 (see FIG. 5 described later) is driven by the internal combustion engine 10. That is, during operation of the internal combustion engine 10, hydraulic pressure is supplied from the hydraulic pump 50 to the VVT 48 via the hydraulic system. The hydraulic system is provided with a hydraulic sensor 52 for detecting the hydraulic pressure by the ECU 54.

  On the other hand, the system of the present embodiment includes an ECU (Electronic Control Unit) 54 for controlling the operating state of the internal combustion engine 10. The ECU 54 is configured by a microcomputer including a storage circuit such as a ROM or a RAM. On the input side of the ECU 54, in addition to the rotation sensor 22, the air flow meter 28, the lift amount sensor 46, the hydraulic pressure sensor 52, and the like described above, a water temperature sensor that detects the cooling water temperature of the internal combustion engine 10 and an accelerator opening degree are detected. A sensor system including an accelerator opening sensor that detects the air-fuel ratio and the air-fuel ratio sensor that detects the air-fuel ratio of the exhaust gas is connected.

  Various actuators including a throttle motor 32, a fuel injection valve 34, and a spark plug 36 are connected to the output side of the ECU 54. The actuator includes an electric actuator provided in devices such as the VVT 48, a variable valve mechanism 68 described later, and an adjuster movable mechanism 82, and an actuator such as an electromagnetic valve that controls a hydraulic circuit of these devices.

  Then, the ECU 54 controls the operation by driving each actuator while detecting the operation state of the internal combustion engine 10 by the sensor system. In addition, when an abnormality occurs in the intake-side valve system 42 including the variable valve mechanism 68, the ECU 54 performs an abnormal lift amount reduction control and an abnormal retardation control which will be described later.

(Valve system)
Next, the intake side valve operating system 42 will be described with reference to FIGS. 2 and 3. 2 shows a perspective view of the valve train 42, and FIG. 3 shows a side view of the valve train 42. As shown in FIG. The exhaust-side valve system 44 is assumed to have substantially the same configuration as that of the intake side, and the description thereof is omitted.

  As shown in FIGS. 2 and 3, the valve train 42 includes end pivot type rocker arms 60 and 60 that open and close two intake valves 38 and 38 provided in each cylinder, respectively. One end side in the length direction of the rocker arm 60 is in contact with a tappet provided at the end of the valve shaft 38 </ b> A of the intake valve 38. The other end side of the rocker arm 60 is supported by a hydraulic lash adjuster 80 described later. Further, a rocker roller 62 is rotatably provided at an intermediate portion in the length direction of the rocker arm 60.

  On the other hand, the intake camshaft 64 of the internal combustion engine 10 is provided with a cam 66 for opening and closing each intake valve 38. The valve train 42 includes a variable valve mechanism 68 disposed between the cam 66 and the rocker arm 60. The variable valve mechanism 68 is configured to variably set the lift amount and operating angle of the intake valve 38, and has a known configuration as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-132326.

  That is, the variable valve mechanism 68 has a control shaft 70 arranged in parallel with the intake camshaft 64 as shown in FIG. The control shaft 70 is rotationally driven by the ECU 54 using an actuator (not shown) or the like. As shown in FIG. 3, a substantially C-shaped control arm 72 is swingably attached to the control shaft 70, and the control arm 72 projects from the control shaft 70 in the radial direction.

  An input roller 74 that receives the input of the cam 66 and two output rollers 76 and 76 that output the force received by the input roller 74 are rotatably attached to the distal end side of the control arm 72. Each output roller 76 is disposed on both axial sides of the input roller 74. Further, two swing cam arms 78 and 78 that receive the output of each output roller 76 are swingably attached to the control shaft 70.

  These swing cam arms 78 are in contact with the rollers 76 on the upper surface side, and are in contact with the rocker rollers 62 of the rocker arms 60 on the lower surface side. Therefore, the input of the cam 66 is transmitted to each rocker arm 60 via the variable valve mechanism 68, and the intake valve 38 is opened and closed by the rocker arm 60.

  Each of the rollers 74 and 76 is held at a position corresponding to the rotation angle of the control shaft 70 between the proximal end side and the distal end side of the swing cam arm 78. The amplitude and timing when the swing cam arm 78 swings change according to the position of the output roller 76. Therefore, according to the variable valve mechanism 68, the lift amount and the operating angle of the intake valve 38 can be controlled in accordance with the rotation angle of the control shaft 70.

(Rush adjuster)
Next, a hydraulic lash adjuster 80 that supports the other end of the rocker arm 60 will be described with reference to FIG. FIG. 4 shows a cross-sectional view of the lash adjuster 80. As shown in this figure, the lash adjuster 80 has a known configuration as disclosed in, for example, Japanese Patent Application Laid-Open No. 2007-192111.

  That is, the lash adjuster 80 includes a bottomed cylindrical housing 80A, a hollow plunger 80B, a plunger spring 80C, a check ball 80D, a check ball spring 80E, and a ball retainer 80F. The plunger 80B is slidably inserted into the housing 80A and is urged in a direction protruding from the housing 80A by a plunger spring 80C.

  A low pressure chamber 80G is provided in the plunger 80B, and a high pressure chamber 80H is defined between the housing 80A and the plunger 80B. The hydraulic oil is supplied to the low pressure chamber 80G from the above-described hydraulic system through the oil hole 80J and the like. On the bottom side of the plunger 80B, a through hole 80K is provided for communicating the low pressure chamber 80G and the high pressure chamber 80H.

  The check ball 80D opens and closes the through hole 80K according to the direction of the force acting on the plunger 80B, thereby adjusting the hydraulic pressure in the high pressure chamber 80H. As a result, the protrusion amount of the plunger 80B relative to the housing 80A is controlled according to the hydraulic pressure in the high pressure chamber 80H and the spring force of the plunger spring 80C. The plunger 80B presses the other end side of the rocker arm 60 upward with a force corresponding to the amount of protrusion.

  Thereby, the lash adjuster 80 maintains the gap dimension between the rocker roller 62 and the valve shaft 38A (so-called tappet clearance) and the gap dimension between the rocker roller 62 and the swing cam arm 78 at zero. According to the lash adjuster 80, thermal deformation or the like of the valve shaft 38A can be absorbed according to the protruding amount of the plunger 80B while suppressing the gap size.

  The lash adjuster 80 supports the other end side of the rocker arm 60 against the pressing force when the rocker roller 62 is pressed downward by the swing cam arm 78 of the variable valve mechanism 68. As a result, the rocker arm 60 tilts downward on one end side with the other end side as a fulcrum by the pushing force of the swing cam arm 78. Thereby, the rocker arm 60 can open the intake valve 38 with a lift amount corresponding to the tilt amount.

(Adjuster movable mechanism)
Next, the adjuster movable mechanism 82 will be described with reference to FIGS. 5 and 6. The adjuster movable mechanism 82 is for displacing the entire lash adjuster 80 in the direction of approaching and separating from the rocker arm 60. FIG. 5 is an overall view of the adjuster mechanism 82, and FIG. 6 is an enlarged view of a main part of the adjuster mechanism 82.

  As shown in these drawings, the adjuster movable mechanism 82 includes an adjuster insertion hole 84, a stopper insertion hole 86, a movable stopper 88, a release spring 90, oil passages 92 and 94, and an OCV 96. The adjuster movable mechanism 82 supports the lash adjuster 80 so as to be displaceable. For this reason, the plunger 80B protrudes from the cylinder head 14 toward the rocker arm 60 in a stretchable state, and the protruding dimension T (see FIG. 5) changes according to the operating state of the adjuster movable mechanism 82.

  The adjuster insertion hole 84 is a bottomed hole provided in the cylinder head 14 and opens at a position facing the rocker arm 60 of each intake valve 38. A lash adjuster 80 is slidably inserted into these adjuster insertion holes 84. In this case, a seal mechanism (not shown) that seals hydraulic oil is provided between the outer peripheral surface of the housing 80A of the lash adjuster 80 and the inner peripheral surface of the adjuster insertion hole 84.

  The lash adjuster 80 can be displaced in the depth direction between the opening side of the adjuster insertion hole 84 and the back side. Hereinafter, the opening side of the adjuster insertion hole 84 is referred to as a normal position, and the back side is referred to as a retracted position. FIG. 5 shows a state in which the lash adjuster 80 is held at the normal position. In this normal position, a receding space 84 </ b> A is secured on the back side of the adjuster insertion hole 84.

  Further, when the lash adjuster 80 is displaced to the retracted position, the protruding dimension T of the plunger 80B protruding from the cylinder head 14 toward the rocker arm 60 is smaller than the normal position. As a result, the tilting amount of the rocker arm 60 with respect to the swinging amount of the swinging cam arm 78 is reduced, and the lift amount of the intake valve 38 is reduced accordingly.

  On the other hand, the stopper insertion hole 86 communicates the two adjuster insertion holes 84 at a position closer to the back. In the stopper insertion hole 86, for example, two movable stoppers 88 formed in a pin shape are provided. These movable stoppers 88 have a function as pistons that slide in the stopper insertion holes 86 by hydraulic pressure.

  That is, each movable stopper 88 protrudes from the stopper insertion hole 86 into the individual adjuster insertion hole 84 or from the adjuster insertion hole 84 to the stopper insertion hole according to the supply state of the hydraulic pressure to the stopper insertion hole 86. It is possible to move back into 86. The movable stopper 88 holds the lash adjuster 80 at the above-described normal position in a state where the movable stopper 88 protrudes into the adjuster insertion hole 84.

  The release spring 90 is made of, for example, a spring installed between the movable stoppers 88, and constitutes release means for releasing the operation of the movable stopper 88. In other words, the release spring 90 urges the movable stoppers 88 on both sides in a direction in which the movable stoppers 88 are retracted into the stopper insertion holes 86. When the movable stopper 88 is retracted into the stopper insertion hole 86, the lash adjuster 80 can be displaced from the normal position to the retracted position.

  Further, the control oil passage 92 supplies hydraulic pressure for causing the movable stopper 88 to protrude into the adjuster insertion hole 84, and is connected to the stopper insertion holes 86 between the movable stoppers 88. The return oil passages 94 return the hydraulic oil in the receding space 84 </ b> A of the adjuster insertion holes 84 to the hydraulic oil tank side, and are connected to the bottom surfaces of the adjuster insertion holes 84.

  These oil passages 92 and 94 are connected to the hydraulic pump 50 and the hydraulic oil tank via an OCV (oil control valve) 96, respectively. The OCV 96 opens and closes the control oil passage 92 according to a control signal input from the ECU 54, and supplies and shuts off the hydraulic pressure to the stopper insertion hole 86. The OCV 96 communicates and blocks between the return oil passage 94 and the hydraulic oil tank by opening and closing the return oil passage 94.

[Operation of Embodiment 1]
First, when the valve train 42 is operating normally, it is confirmed that the valve is operating normally by the output of the lift amount sensor 46 or the like. In this case, the ECU 54 supplies the hydraulic pressure from the control oil passage 92 into the stopper insertion hole 86 by holding the OCV 96 at the normal position. As a result, the movable stopper 88 is pushed out from the stopper insertion hole 86 by hydraulic pressure and protrudes into the adjuster insertion hole 84 against the spring force of the release spring 90. As a result, the lash adjuster 80 is prevented from retreating in the adjuster insertion hole 84 by the movable stopper 88 and is held at the normal position.

  In this state, during operation of the internal combustion engine 10, the intake camshaft 64 rotates and the input of the cam 66 is transmitted to the rocker roller 62 via the variable valve mechanism 68. At this time, the other end side of the rocker arm 60 is supported by the lash adjuster 80 in the normal position. For this reason, one end side of the rocker arm 60 is tilted downward following the profile of the cam 66. As a result, the intake valve 38 is pushed in the valve opening direction by the rocker arm 60 and opens against the spring force of a valve spring (not shown).

  On the other hand, when an abnormality occurs in the valve train 42, the abnormality is detected by the lift amount sensor 46. In this case, the ECU 54 performs the abnormal lift amount reduction control and the abnormal retardation control described below.

(Abnormal lift reduction control)
When the abnormality of the valve train 42 is detected and it is determined that the VVT 48 cannot be operated quickly, the ECU 54 executes the abnormal lift amount reduction control. The state in which the VVT 48 cannot operate quickly is, for example, a case where the internal combustion engine 10 is operated at a low speed or a low temperature.

  In the abnormal lift amount reduction control, the supply of hydraulic pressure from the control oil passage 92 to the stopper insertion hole 86 is stopped by switching the OCV 96 to the position for dealing with the abnormality. Further, the return oil passage 94 is communicated with the hydraulic oil tank side.

  As a result, each movable stopper 88 is retracted into the stopper insertion hole 86 by the spring force of the release spring 90 and does not protrude into the adjuster insertion hole 84. Therefore, the lash adjuster 80 is pushed into the adjuster insertion hole 84 when the input of the cam 66 acts through the rocker arm 60, and is displaced to the retracted position described above. At this time, the hydraulic oil that has accumulated in the receding space 84 </ b> A of the adjuster insertion hole 84 is returned to the hydraulic oil tank by the return oil passage 94.

  Thus, in the state where the lash adjuster 80 is retracted, the protruding dimension T of the plunger 80B is decreased, and the plunger 80B is displaced in a direction away from the rocker arm 60. As a result, the fulcrum of the rocker arm 60 supported by the plunger 80B (that is, the fulcrum when the rocker arm tilts) is also displaced in the direction away from the swing cam arm 78 of the variable valve mechanism 68. For this reason, the tilting amount of the rocker arm 60 with respect to the swinging amount of the swinging cam arm 78 becomes small, and accordingly, the lift amount of the intake valve 38 decreases.

  Therefore, for example, even when a failure occurs such that the operating state of the variable valve mechanism 68 is fixed on the large lift amount side, the actual lift amount of the intake valve 38 is reduced by the abnormal lift amount reduction control. It is forcibly changed to. Therefore, the intake valve 38 can be opened and closed without interfering with the piston 16 even when an abnormality occurs.

(Delay control when abnormal)
Further, the ECU 54 executes the retard control at the time of abnormality by outputting a control signal for retarding to the VVT 48 when the abnormality of the valve train 42 is detected. In the abnormal time retarding control, the phase of the intake valve 38 is retarded by the VVT 48, and the valve opening timing of the intake valve 38 is held at a position away from the intake top dead center. For this reason, when the variable valve mechanism 68 fails, interference between the intake valve 38 and the piston 16 can be avoided by the retard control at the time of abnormality if the VVT 48 operates quickly.

[Specific Processing for Realizing Embodiment 1]
FIG. 7 is a flowchart of a routine executed by the ECU 54 in order to realize the system operation of the present embodiment. Note that the routine shown in FIG. 7 is started when the internal combustion engine is started, and is repeatedly executed at regular intervals.

  First, at step 100, the engine speed of the internal combustion engine 10 is detected by the rotation sensor 22. The hydraulic pressure of the hydraulic system is detected by the hydraulic sensor 52. In step 102, the lift amount of the intake valve 38 is detected by the lift amount sensor 46.

  Next, in step 104, it is determined whether or not an abnormality has occurred in the variable valve mechanism 68 (the valve system 42). This determination process is performed by comparing the target lift amount set by the ECU 54 with the actual lift amount detected by the lift amount sensor 46.

  If “YES” is determined in step 104, the process proceeds to step 106 and subsequent steps in order to cope with the abnormality of the valve train 42. Further, when it is determined as “NO” in Step 104, the valve train 42 is operating normally, and thus the process is ended as it is.

  Next, in step 106, the above-described retard control at the time of abnormality is executed, and the phase of the intake valve 38 is retarded by the VVT 48. In step 108, it is determined whether or not an execution condition for performing the abnormal lift amount reduction control is satisfied. This execution condition is satisfied, for example, when the engine speed is lower than the rotation determination value or when the hydraulic pressure of the hydraulic system is lower than the pressure determination value. These determination values are stored in the ECU 54 in advance.

  If “YES” is determined in step 108, the response of the VVT 48 is not good, so that it is determined that the abnormal-time retardation control alone is insufficient, and the process proceeds to step 110. In step 110, the abnormal lift amount reduction control is executed to lower the fulcrum of the rocker arm 60 by the lash adjuster 80 and reduce the lift amount of the intake valve 38.

  If “NO” is determined in step 108, it is determined that the abnormal lift amount reduction control is not necessary because the responsiveness of the VVT 48 is good. Therefore, in this case, the abnormal lift amount reduction control is not executed, and only the abnormal retardation control is executed.

  As described above in detail, according to the present embodiment, the ECU 54 can reduce the projecting dimension T of the plunger 80B of the lash adjuster 80 when detecting an abnormality in the valve train 42, whereby the intake air The lift amount of the valve 38 can be forcibly reduced. The lift amount reducing operation can be performed promptly when an abnormality is detected regardless of the engine speed or temperature state of the internal combustion engine 10.

  That is, in the abnormal lift amount reduction control, only the protrusion dimension T of the lash adjuster 80 is reduced, so that a large hydraulic actuator such as a hydraulic variable valve timing mechanism is not required. For this reason, even if the abnormal lift amount reduction control is executed during operation at low rotation or low temperature, there is almost no response delay due to insufficient hydraulic pressure or increased oil viscosity. Therefore, the abnormal lift amount reduction control can reliably avoid the intake valve 38 from interfering with the piston 16 even during operation at a low rotation or low temperature, and prevent a chain failure of these components. can do.

  In this embodiment, the adjuster movable mechanism 82 is used. Thereby, the adjuster movable mechanism 82 can support the entire lash adjuster 80 so as to be displaceable with respect to the rocker arm 60. Therefore, when an abnormality is detected, the protrusion dimension T of the plunger 80B can be changed by the adjuster movable mechanism 82 regardless of the expansion / contraction operation of the lash adjuster 80 itself.

  Therefore, the protrusion dimension T of the plunger 80B can be reliably reduced to the target value at the time of abnormality. Further, for example, by simply adding an adjuster movable mechanism 82 to the conventional lash adjuster 80, a mechanism for coping with an abnormality can be easily realized, and the structure of the lash adjuster 80 is prevented from becoming complicated to prepare for an abnormality. be able to.

  Further, according to the adjuster movable mechanism 82, the lash adjuster 80 can be held on the opening side (normal position) of the adjuster insertion hole 84 by the movable stopper 88 when the valve train 42 is in a normal state. Then, the lash adjuster 80 can be operated at the normal position. Further, when an abnormality in the valve train 42 is detected, the operation of the movable stopper 88 can be canceled by the release spring 90.

  Thereby, the ECU 54 can displace the lash adjuster 80 to the back side (retracted position) of the adjuster insertion hole 84, and can reduce the protruding dimension T of the plunger 80B. Therefore, according to the adjuster movable mechanism 82, the displacement mechanism of the lash adjuster 80 can be easily realized.

  Further, in the present embodiment, the abnormal time retardation control is also implemented using the VVT 48. According to the abnormal time retardation control, when the abnormality is detected, the opening timing of the intake valve 38 can be separated from the intake top dead center, and interference between the intake valve 38 and the piston 16 can be prevented. If the responsiveness of the VVT 48 is good, the abnormal lift amount reduction control and the abnormal retardation control can be performed together, thereby more reliably protecting the intake valve 38 and the piston 16. it can.

  In the above embodiment, step 110 in FIG. 7 shows a specific example of the abnormal time lift amount reducing means, and step 106 shows a specific example of the abnormal time retarding means.

  In the embodiment, the lash adjuster 80 is supported by the adjuster movable mechanism 82 so as to be displaceable, and the entire lash adjuster 80 is retracted when the valve train 42 is abnormal. However, the present invention may be configured to use the lash adjuster 80 that can be greatly reduced without mounting the adjuster movable mechanism 82. In this case, when the valve operating system 42 is abnormal, the plunger 80B of the lash adjuster 80 may be moved toward the back side of the housing 80A so as to be larger than the normal use range, and thereby the plunger 80B may be retracted.

  In the embodiment, when the valve train 42 is abnormal, the abnormal lift amount reduction control is executed only when the internal combustion engine 10 is operated at a low speed or a low temperature. However, the present invention is not limited to this, and when the valve train 42 is abnormal, the abnormal lift amount reduction control may always be executed regardless of the operating state of the internal combustion engine 10. In this case, it is not always necessary to execute the abnormal time retardation control.

  In the embodiment, the lash adjuster 80 is displaced by the hydraulic adjuster movable mechanism 82. However, the present invention is not limited to this. For example, an electric adjuster movable mechanism that drives the movable stopper 88 by an electromagnetic actuator or the like may be used.

  Furthermore, in the embodiment, the configuration is applied to the intake valve 38 of the internal combustion engine 10, but the present invention is not limited to this and may be applied to the exhaust valve 40.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall view for explaining a system configuration according to a first embodiment of the present invention. It is a perspective view which shows the valve operating system by the side of intake. FIG. 3 is a side view of the valve train of FIG. 2 as viewed from the axial direction of the camshaft. It is sectional drawing which shows the structure of a lash adjuster. It is a general view showing an adjuster movable mechanism on the intake side. It is a principal part enlarged view which shows the vicinity of the movable stopper in FIG. It is a flowchart of the routine performed in Embodiment 1 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 12 Cylinder block 14 Cylinder head 16 Piston 18 Combustion chamber 20 Crankshaft 22 Rotation sensor 24 Intake passage 26 Exhaust passage 28 Air flow meter 30 Throttle valve 32 Throttle motor 34 Fuel injection valve 36 Spark plug 38 Intake valve 38A Valve shaft 40 Exhaust Valves 42 and 44 Valve system 46 Lift amount sensor (abnormality detection means)
48 VVT (Variable valve timing mechanism)
50 Hydraulic pump 52 Hydraulic sensor 54 ECU
60 Rocker arm 62 Rocker roller 64 Intake cam shaft 66 Cam 68 Variable valve mechanism 70 Control shaft 72 Control arm 74 Input roller 76 Output roller 78 Swing cam arm 80 Rush adjuster 82 Adjuster movable mechanism 84 Adjuster insertion hole 84A Retraction space 86 Stopper insertion Hole 88 Movable stopper 90 Release spring (release means)
92,94 Oil passage 96 OCV
T Protrusion dimension

Claims (4)

A valve provided on a cylinder head of an internal combustion engine and driven to open and close by a cam;
A rocker arm in which one side in the length direction is in contact with the valve, and a rocker roller that receives the input of the cam is disposed in the middle in the length direction;
A lash adjuster having a plunger projecting from the cylinder head toward the rocker arm so as to be extendable and contractable, and supporting the other side of the rocker arm by the plunger to suppress the tappet clearance of the valve;
A variable valve mechanism that variably sets at least the lift amount among the opening and closing characteristics of the valve;
An abnormality detecting means for detecting an abnormality of the variable valve mechanism;
When an abnormality of the variable valve mechanism is detected by the abnormality detection means, an abnormal-time lift amount reduction means for reducing the protrusion amount of the plunger to reduce the lift amount of the valve;
An internal combustion engine comprising: An adjuster movable mechanism capable of displacing the entire lash adjuster in a direction approaching and separating from the rocker arm;
2. The internal combustion engine according to claim 1, wherein the abnormal lift amount reducing means is configured to displace the lash adjuster in a direction away from the rocker arm by the adjuster moving mechanism when an abnormality of the variable valve mechanism is detected. organ. The adjuster movable mechanism is
An adjuster insertion hole that opens to the cylinder head at a position facing the rocker arm, and into which the lash adjuster is slidably inserted,
A movable stopper that holds the lash adjuster on the opening side of the adjuster insertion hole when the abnormal lift amount reducing means is in an inoperative state;
A release means for releasing the movable stopper when the abnormal-time lift amount reducing means is activated, and allowing the lash adjuster to be displaced to the back side of the adjuster insertion hole;
An internal combustion engine according to claim 2, comprising: A variable valve timing mechanism for variably setting the phase of the valve;
An abnormal time retarding means for retarding the phase of the valve by the variable valve timing mechanism when an abnormality of the variable valve mechanism is detected by the abnormality detecting means;
The internal combustion engine according to any one of claims 1 to 3, further comprising:

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