JP2010059945A - Variable valve gear device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve gear device for an internal combustion engine which is suitable for reducing variation of an air-fuel ratio between cylinders in an idling operation at a high oil temperature. <P>SOLUTION: The variable valve gear device has a lift and work-angle variable mechanism 1 capable of continuously changing lift characteristics corresponding to at least one of valve-lift amounts and work-angles of intake valves 6 of a plurality of cylinders, a hydraulic lash adjuster 4 arranged on a transmitting system for transmitting an operation of the lift and work-angle variable mechanism 1 to the intake valve 6 of each cylinder, and an engine controller 5 as a control means for increasing the number of engine rotation by increase-compensating the number of setting rotation when temperature of lubricating oil supplied to the hydraulic lash adjuster 4 exceeds a preset temperature under an operating condition wherein the lift characteristics is controlled to a designated small-setting value. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine including a variable lift / operating angle mechanism capable of continuously changing at least one of a valve lift amount and an operating angle of an intake valve in the internal combustion engine.

  Conventionally, a variable valve operating apparatus for an internal combustion engine has been proposed that includes a variable lift / operating angle mechanism capable of continuously changing both the valve lift amount and the operating angle of an intake valve (see Patent Document 1).

This makes it possible to variably control the amount of air flowing into the cylinder without depending on the opening control of the throttle valve. In particular, in a region where the load is small, so-called throttleless operation or sufficient opening of the throttle valve is sufficient. Therefore, the pumping loss can be greatly reduced.
JP 2001-173469 A

  When controlling the intake air amount using the lift / operating angle variable mechanism as in the above-mentioned conventional example, in order to realize a very small intake air amount as in idling, the intake valve lift amount (maximum The lift amount is a minimum lift of about 1 mm, for example. In such a minimal lift state, the amount of air flowing into the cylinder varies relatively greatly due to slight variations in the lift amount due to the clearance between the lift / operating angle variable mechanism of each cylinder and each intake valve, Moreover, since the intake air amount itself is small, variations in the air-fuel ratio among the cylinders are likely to occur.

  In order to reduce slight variations in the lift amount due to the clearance between the lift / operating angle variable mechanism of each cylinder and each intake valve, a hydraulic lash adjuster (HLA) is equipped, It is effective to minimize the clearance of the components of each cylinder and the clearance of the operation transmission path that transmits the operation of the lift / operating angle variable mechanism to the intake valve via the valve rocker arm. However, when the oil temperature is high, the amount of hydraulic oil leaked down from the hydraulic lash adjuster varies greatly between the cylinders, and the amount of lift varies greatly. For this reason, when the oil temperature is high, variation in the air amount between the cylinders cannot be eliminated, and there is a possibility that engine vibration increases, combustion stability decreases, and exhaust emissions deteriorate.

  Accordingly, the present invention has been made in view of the above problems, and an object thereof is to provide a variable valve operating apparatus for an internal combustion engine that is suitable for reducing variation in air-fuel ratio between cylinders in an idle operation state at a high oil temperature. To do.

  The present invention relates to a variable lift / operating angle mechanism capable of continuously changing a lift characteristic corresponding to at least one of a valve lift amount and an operating angle of an intake valve of a plurality of cylinders, a cylinder body, and a slidable to the cylinder body A plunger that forms a high-pressure chamber that is energized and stretched from the cylinder body by an elastic means, and that contains lubricating oil, and when the high-pressure chamber is expanded by the plunger and hydraulic oil is introduced and the high-pressure chamber is compressed A hydraulic lash adjuster interposed in a transmission system for transmitting the operation of the lift / operating angle variable mechanism to the intake valve of each cylinder, and a valve for preventing hydraulic oil from flowing out from the high pressure chamber, When the temperature of the lubricating oil supplied to the hydraulic lash adjuster exceeds a preset set temperature under an operating state in which the lift characteristic is controlled to a predetermined small set value, the set rotational speed is set. Temperature correction to be characterized by and a control means for raising the engine speed.

  Therefore, in the present invention, in the variable valve operating apparatus including the lift / operating angle variable mechanism and the hydraulic lash adjuster, the hydraulic lash adjuster is supplied to the hydraulic lash adjuster under an operation state in which the lift characteristic is controlled to a predetermined small set value. When the lubricating oil temperature exceeds the preset temperature, increase the engine speed by increasing the engine speed to reduce the amount of leak down from the hydraulic lash adjuster in the low oil temperature range. This can reduce the variation in lift characteristics between cylinders, reduce engine vibration, and improve fuel efficiency and exhaust emission.

  Hereinafter, a variable valve operating apparatus for an internal combustion engine of the present invention will be described based on each embodiment. 1 to 5 show a first example of a variable valve operating apparatus for an internal combustion engine according to a first embodiment to which the present invention is applied. FIG. 1 is a system configuration diagram including a perspective view of the variable valve operating apparatus. FIG. 3 is a cross-sectional view of the variable valve operating apparatus, FIG. 3 is a cross-sectional view showing a hydraulic lash adjuster and a lubricating oil supply path used in the variable valve operating apparatus, and FIG. 4 is a flowchart showing a control flow according to the present embodiment. . The variable valve operating apparatus of this embodiment will be described as being applied to an internal combustion engine that includes two intake valves per cylinder and variably controls the valve lift of each intake valve according to the engine operating state.

  1 to 3, a variable valve operating apparatus for an internal combustion engine includes a lift / operation angle variable mechanism 1 that changes a lift / operation angle of an intake valve 6 and a phase of a center angle of the lift (phase with respect to a crankshaft (not shown)). ) Is advanced or retarded, a rocker arm mechanism 3 that includes a hydraulic lash adjuster 4 and transmits the operation of the lift / operating angle variable mechanism 1 to the intake valve 6, the lift / operating angle variable mechanism 1, and An engine controller 5 for controlling the phase variable mechanism 2.

  The lift / operating angle variable mechanism 1 includes a drive shaft 10 rotatably supported by a cam bracket (not shown) on a cylinder head, a drive cam 11 fixed to the drive shaft 10 by pins or the like, and the drive shaft. A control shaft 12 including a main shaft 12A that is disposed in parallel with the drive shaft 10 at a position above 10 and is rotatably supported by a cam bracket, and eccentric shafts 12B that are offset via webs 12C on both sides of the main shaft 12A; A swing arm 13 swingably supported on the eccentric shaft 12B of the control shaft 12 and a swing cam that is swingably supported by the drive shaft 10 and abuts on a rocker arm 27 with a roller 28 of each intake valve 6. 14.

  The drive cam 11 and the swing arm 13 are linked by a link arm 15, and the swing arm 13 and the swing cam 14 are linked by a link rod 16. The drive shaft 10 is driven by a crankshaft of an engine via a timing chain or timing belt (not shown). The drive cam 11 has a circular outer peripheral surface centered at a point offset from the shaft center of the drive shaft 10 by a predetermined amount, and an annular portion of the link arm 15 is rotatably fitted on the outer peripheral surface. Yes.

  The oscillating arm 13 has a base portion divided into two parts, a bearing bracket 13A and an arm portion 13B provided with a connecting portion to the link arm 15 and the link rod 16 with the eccentric shaft 12B interposed therebetween, and both are fastened. By integrating with the bolt 17, a bearing hole 18 is formed between the two so as to be swingably fitted to the eccentric shaft 12 </ b> B of the control shaft 12, and is supported by the eccentric shaft 12 </ b> B of the control shaft 12 so as to be swingable. The distal end extending to one side of the arm portion 13B is linked to the upper end portion of the link rod 16 via a connecting pin 19, and is slightly closer to the base than the distal end portion on the same side as the distal end portion. The arm portion 113B of the link arm 15 is linked through a connecting pin 20 that protrudes in the axial direction from the axial end portion of the base portion. That is, the link arm 15 and the link rod 16 are disposed on the same side, but are arranged at different positions in the axial direction.

  The control shaft 12 includes a main shaft 12A that is rotatably supported by the cam bracket, and an eccentric shaft 12B that is eccentric to the main shaft 12A via a web 12C, and changes the angular position of the control shaft 12. As a result, the position of the eccentric shaft 12B is changed, and the swing center position of the swing arm 13 is also changed accordingly. The axial length of the eccentric shaft 12B of the control shaft 12 is set to a length that accommodates the base portion of the swing arm 13 and the connecting pin 20 protruding in the axial direction from the base portion, and is provided at both ends of the eccentric shaft 12B. The arranged web 12C and the link arm 15 and the link rod 16 are arranged so as not to interfere with each other.

  Two swing cams 14 corresponding to the rocker arms 27 of the intake valves 6 are integrally formed on a cylindrical cam shaft 25 that is fitted to the outer periphery of the drive shaft 10 and is rotatably supported. A lower end portion of the link rod 16 is linked to an end portion that extends laterally from the moving cam 14 via a connecting pin 21. The cam shaft 25 is supported on the outer periphery of the drive shaft 10 so as to be rotatable, and at the outer periphery, the end of the cam shaft 25 is supported by the cam bracket so as to be swingable, and the intermediate portion swings on the intermediate bracket provided on the cylinder head. It is supported movably. On the lower surface of each oscillating cam 14, a base circle surface concentric with the drive shaft 10 and a cam surface extending in a predetermined curve from the base circle surface are continuously formed. The base surface and the cam surface come into contact with the upper surface of the roller 28 of the rocker arm 27 of each intake valve 6 according to the swing position of the swing cam 14.

  That is, the base circle surface is a zone where the lift amount is “0” as a base circle zone, and when the swing cam 14 swings and the cam surface contacts the roller 28 of the rocker arm 27, the intake valve 6 gradually increases. Will lift. A slight lap section is provided between the base circle section and the lift section.

  The control shaft 12 is configured to rotate within a predetermined angle range by a control actuator 23 provided at one end. The control actuator 23 is composed of an electric actuator, for example, and is controlled by a control signal from the engine controller 5. The rotation angle of the control shaft 12 is detected by a control shaft sensor (not shown).

  When the drive shaft 10 rotates, the variable lift / operating angle mechanism 1 configured as described above moves the link arm 15 up and down by the cam action of the drive cam 11, and the swing arm 13 swings accordingly. . The swing of the swing arm 13 is transmitted to the swing cam 14 via the link rod 16 to swing the swing cam 14. The rocker arm 27 is pressed by the cam action of the swing cam 14 and acts to lift the intake valve 6.

  When the angular position of the control shaft 12 is changed via the control actuator 23, the initial position of the swing arm 13 changes and the initial swing position of the swing cam 14 changes. For example, in the low-speed and low-load operation state of the internal combustion engine, the eccentric shaft 12B is controlled to move downward (close to the drive shaft 10) in the figure (clockwise position in FIG. 2). The base portion is positioned below, and the end of the swing cam 14 on the side of the connecting pin 21 is relatively lifted upward. That is, the initial position of the swing cam 14 is inclined in a direction in which the cam surface is separated from the roller 28 of the rocker arm 27. Therefore, when the swing cam 14 swings as the drive shaft 10 rotates, the base circle surface is long and keeps contacting the roller 28 of the rocker arm 27, and the period during which the cam surface contacts the roller 28 of the rocker arm 27 is short. . Therefore, the lift amount is reduced as a whole, and the angle range from the opening timing to the closing timing, that is, the operating angle is also reduced.

  On the contrary, in the high-rotation and high-load operation state of the internal combustion engine, the eccentric shaft 12B is controlled so as to move upward in the drawing away from the drive shaft 10 (counterclockwise position in FIG. 2). The base portion is located on the upper side, and the end portion of the swing cam 14 on the side of the connecting pin 21 is relatively pushed down. FIG. 2 shows a state of an intermediate operating angle at which the maximum input load acts. That is, the initial position of the swing cam 14 is inclined in a direction in which the cam surface approaches the roller 28 of the rocker arm 27. Accordingly, when the swing cam 14 swings as the drive shaft 10 rotates, the portion of the rocker arm 27 that contacts the roller 28 immediately shifts from the base surface to the cam surface. Therefore, the lift amount is increased as a whole, and the operating angle is increased.

  Since the initial position of the eccentric shaft 12B can be continuously changed, the valve lift characteristic is continuously changed accordingly. That is, the lift and the operating angle can be continuously expanded and contracted simultaneously. Depending on the layout of each part, for example, the opening timing and closing timing of the intake valve 6 change substantially symmetrically with the change in the lift and operating angle.

  The phase variable mechanism 2 includes a sprocket 22 provided at a front end portion of the drive shaft 10, and a phase control actuator 23 that relatively rotates the sprocket 22 and the drive shaft 10 within a predetermined angle range. , Is composed of. The sprocket 22 is interlocked with the crankshaft via a timing chain or a timing belt (not shown). The phase control actuator 23 is controlled by a control signal from the engine controller 5. Due to the action of the phase control actuator 23, the sprocket 22 and the drive shaft 10 are relatively rotated, and the lift center angle in the valve lift is retarded. That is, the lift characteristic curve itself does not change, and the whole advances or retards. This change can also be obtained continuously. The control state of the phase variable mechanism 2 is detected by a drive shaft sensor (not shown) that responds to the rotational position of the drive shaft 10.

  Further, as shown in FIG. 2, the intake valve 6 of the present embodiment is configured to be opened and closed by a rocker arm 27 with a roller 28, and the base of the rocker arm 27 is operated by receiving supply of lubricating oil. A hydraulic lash adjuster 4 (HLA) is provided.

  As shown in FIG. 3, the hydraulic lash adjuster 4 is held by a bottomed cylindrical cylinder body 30 held by a cylinder head and a plunger hole formed in the cylinder body 30 so as to be slidable up and down. And a substantially covered cylindrical plunger 31.

  The plunger 31 has an upper end formed in a hemispherical shape having substantially the same curvature as the lower surface of one end of the rocker arm 27, and mixed with hydraulic oil in a reservoir chamber 32 described later at a substantially central position of the tip. A bleeder hole 32A for discharging air is provided.

  The plunger 31 is provided with a partition wall 34 that separates a reservoir chamber 32 and a high-pressure chamber 33 formed between the inside of the plunger 31 and the plunger hole of the cylinder body 30 on the lower end side. An oil hole 35 communicating with the reservoir chamber 32 and the high-pressure chamber 33 is formed at a substantially central position of the partition wall 34. The high pressure chamber 33 is surrounded by a plunger hole of the cylinder body 30 and a partition wall 34 of the plunger 31, and a check valve 36 for opening and closing the oil hole 35 is disposed.

  The check valve 36 includes a check ball 36A that allows hydraulic oil to flow only from the reservoir chamber 32 through the oil hole 35 into the high-pressure chamber 33, a retainer 36B formed in a substantially bowl shape, and an interior of the retainer 36B. The plunger 31 and the cylinder body 30 are separated from each other while the first spring 36C having a small spring force that is held and urges the check ball 36A in the closing direction and the retainer 36B is pressed toward the partition wall 34. And a second spring 36D having a relatively large spring force to be urged.

  The lubricating oil from the main gallery 40 of the internal combustion engine is supplied to the reservoir chamber 32 through a groove provided on the outer periphery of the cylinder body 30 and a through hole penetrating the cylinder body 30 in the radial direction. Note that 41 is a lubrication pump, 42 is an oil filter, 43 is an oil pan, and 44 is a relief valve.

  In the hydraulic lash adjuster 4, the plunger 31 is always urged upward by the second spring 36 </ b> D and is in elastic contact with one end of the rocker arm 27. The operation of the variable lift / operating angle mechanism 1 causes the rocker arm 27 to swing with the hydraulic lash adjuster 4 as a fulcrum, thereby opening and closing the intake valve 6.

  When the intake valve 6 is closed and a gap is generated between the outer peripheral surface of the swing cam 14 and the outer peripheral surface of the roller 28 in the base circle region, the biasing force of the second spring 36D When the plunger 31 is slightly raised and the volume of the high pressure chamber 33 is increased as the plunger 31 is raised, the hydraulic oil always filled in the reservoir chamber 32 by the oil pump 41 is transferred from the reservoir chamber 32 to the check valve. 36 is opened and flows into the high pressure chamber 33. As a result, since the gap between the other end of the rocker arm 27 and the upper end of the valve stem is maintained to be zero, it is possible to prevent the occurrence of sound and the like.

  The engine controller 5 includes a detection signal from an air-fuel ratio sensor 45 for detecting an air-fuel ratio of exhaust gas, an engine speed signal and a crank angle position signal based on a crank angle sensor 46, and an accelerator pedal opening operated by a driver. A detection signal from an accelerator opening sensor 47 that detects (depression amount), a detection signal from a cooling water temperature sensor (not shown), a detection signal from an oil temperature sensor 48 that detects lubricating oil temperature, and the like are input. Based on the above, in addition to the valve lift characteristics of the variable valve device, the injection amount and injection timing of the fuel injection valve 50, the ignition timing of the ignition plug 51, the opening of the throttle valve 52, and the like are controlled. The throttle valve 52 includes an actuator composed of an electric motor, the opening degree of which is controlled by a control signal given from the engine controller 5, and based on a detection signal from a sensor that detects the actual opening degree of the throttle valve 52, The throttle valve opening is closed-loop controlled to the target opening.

  The variable valve operating apparatus including the lift / operating angle variable mechanism 1 and the phase variable mechanism 2 described above can arbitrarily control the opening timing and closing timing of the intake valve 6. By controlling the valve closing timing (IVC), the intake amount into the cylinder, that is, the cylinder air amount can be adjusted.

  The variable valve operating device is based on an engine speed signal based on a crank angle sensor 47 input to the controller 5, an accelerator position signal based on an accelerator position sensor 46, a coolant temperature signal indicating a warm-up state, and the like. The engine load is determined, and the lift amount and valve closing timing of the intake valve 6 are set according to the determined engine load.

  That is, when the engine is under a low load, the intake valve 6 is opened / closed at a low lift / small operating angle by the lift / operating angle variable mechanism 1 and at the early stage the phase variable mechanism 2 has greatly advanced from the bottom dead center BDC to the advance side. Is set to close (early closing IVC). The gas flow state when the intake valve 6 is opened is not affected by the port shape of the intake port, and the gas flow in the combustion chamber is determined mainly by the valve opening shape of the intake valve 6 and the shape near the outlet. It has become.

  As the engine load increases, the lift amount and operating angle by the variable lift / operating angle mechanism 1 are increased, and the valve closing timing (IVC) by the phase variable mechanism 2 is brought closer to the bottom dead center BDC side (advance angle). Set the amount to be smaller). In this case, the opening timing (IVO) of the intake valve 6 is set so as to start opening at least from the piston top dead center TDC.

  As described above, according to the variable valve operating apparatus 2 in which the lift / operating angle variable mechanism 1 and the phase variable mechanism 2 are combined, both the intake valve opening timing (IVO) and the intake valve closing timing (IVC) are independently determined. It can be arbitrarily controlled, and in the low load range, by reducing the lift amount (maximum lift amount), it is possible to limit the intake air amount according to the load. In a region where the lift amount is large to some extent, the air amount flowing into the cylinder is mainly determined by the opening / closing timing of the intake valve 6, whereas in a state where the lift amount is sufficiently small, the air amount is mainly determined by the lift amount. .

  In the configuration as described above, the intake air amount is controlled so that the required torque determined by the accelerator pedal opening degree is obtained. The opening degree of the electronically controlled throttle valve 52 is basically the exhaust gas recirculation or the like. Is controlled so that the minimum negative pressure required is generated in the collector. Then, the variable valve operating apparatus is controlled so that the amount of air flowing into the cylinder is optimized under the suction negative pressure close to the atmospheric pressure.

  In a low load region such as during idling, the lift amount of the intake valve 6 is controlled to a predetermined small set value of about 1 mm, typically the minimum set value, by the lift / operating angle variable mechanism 1, and according to the lift amount. The air volume is limited. Therefore, variation in lift amount of each cylinder caused by dimensional error or assembly error of each cylinder part in the variable lift / operating angle mechanism 1 is suppressed, and variation in air amount of each cylinder is controlled within an allowable range. To. Further, the hydraulic lash adjuster 4 is used to provide an operation transmission path for transmitting the clearance of each cylinder part in the lift / operating angle variable mechanism 1 and the operation of the lift / operating angle variable mechanism 1 to the intake valve 6 via the valve rocker arm 27. It is configured to minimize clearance.

  By the way, when the intake valve 6 operated by the lift / operating angle variable mechanism 1 has the same operating angle, the valve opening time becomes longer as the engine speed decreases, and it is as low as when idling. In the load region, the valve opening time is the longest. For this reason, since the operation period during which the rocker arm 27 is pressed by the lift / operating angle variable mechanism 1 also becomes longer, the operation time of the pressing force applied to the hydraulic lash adjuster 4 also becomes longer.

  When the temperature of the lubricating oil supplied to the hydraulic lash adjuster 4 is maintained within a prescribed temperature range (for example, around 80 ° C.), the viscosity of the lubricating oil is also maintained normally. The lash adjuster 4 operates with high accuracy and operates to minimize the clearance of each lift / operating angle variable mechanism 1. Therefore, variation in the lift amount of each cylinder is suppressed, variation in the air amount of each cylinder is controlled within an allowable range, and a relatively large variation in the air amount of each cylinder can be suppressed. For this reason, the fuel injection amount of each cylinder is controlled to be the target air-fuel ratio (for example, the theoretical air-fuel ratio) in all the cylinders based on the detection signal of the air-fuel ratio sensor 45 in the exhaust system, and the actual air-fuel ratio of each cylinder is controlled. It is possible to prevent the fuel ratio from deviating from the target air-fuel ratio to the rich side or the lean side, thereby preventing an increase in vibration or a decrease in exhaust emission due to a combustion fluctuation between the cylinders.

  However, when the temperature of the lubricating oil supplied to the hydraulic lash adjuster 4 exceeds a specified temperature range and becomes a high temperature (for example, 120 ° C. or higher), the viscosity of the lubricating oil is reduced. As a result, the amount of leakage of the lubricating oil from the high pressure chamber 33 of the hydraulic lash adjuster 4 increases, and the function of suppressing the clearance of each lift / operating angle variable mechanism 1 decreases. For this reason, a slight variation occurs in the lift amount of each cylinder, and a variation occurs in the air amount of each cylinder. For this reason, although the fuel injection amount of each cylinder is controlled to be the target air-fuel ratio (for example, the theoretical air-fuel ratio) in all the cylinders based on the detection signal of the air-fuel ratio sensor 45 in the exhaust system, This causes the air / fuel ratio of the engine to deviate from the target air / fuel ratio to the rich side or the lean side, leading to an increase in vibration due to combustion fluctuations between cylinders and a decrease in exhaust emission.

  Therefore, in the present embodiment, in order to reduce or eliminate the influence of the variation in the lift amount between the cylinders by the hydraulic lash adjuster 4 as described above, the lubrication detected by the oil temperature sensor 48 in a low load region such as during idling. When the oil temperature exceeds a preset temperature, the idle speed is increased to reduce the amount of hydraulic leak down generated in the hydraulic lash adjuster 4.

  FIG. 4 is a flowchart showing a control flow according to the present embodiment. First, in step S1, the engine operating conditions are read by the crank angle sensor 47, the accelerator opening sensor 46, the air-fuel ratio sensor 45, and the oil temperature signal is read from the oil temperature sensor 48, and the process proceeds to step S2.

  In step S <b> 2, it is determined whether or not an idle operation condition is set as a predetermined operation condition for changing the idle speed. That is, in the idling operation condition, since the valve lift amount and the operating angle of the lift / operating angle variable mechanism 1 are minimized as described above, the variation of the lift / operating angle between the cylinders due to the clearance is easily noticeable. In addition, since the intake air amount itself is small, the air-fuel ratio between the cylinders is likely to fluctuate, and because the vehicle is stopped, it is easy to give discomfort to the passenger due to engine vibration. If it is not an idle operation condition, the process is terminated.

  In the case of the idling operation condition, the process proceeds from step S2 to step S3, and it is determined whether or not the oil temperature signal from the oil temperature sensor 48 exceeds a preset oil temperature (for example, 120 ° C.). If the oil temperature does not reach the set oil temperature, it is determined that the leak-down amount in the hydraulic lash adjuster 4 is within an allowable range, and the variation in lift characteristics between the cylinders due to the clearance is small. To go to the preset idle speed at normal time.

  On the other hand, if the oil temperature exceeds the set oil temperature, it is determined that the amount of leak-down in the hydraulic lash adjuster 4 exceeds the allowable range, and the variation in lift characteristics between the cylinders due to the clearance is large. The process proceeds to step S5 to set a corrected idle speed higher than a preset normal idle speed. Note that when the internal combustion engine is operated for a long time in a high load state, specifically, when the vehicle is run at a low speed on a long uphill for a long time (also referred to as towing), the lubricating oil temperature of the internal combustion engine is The temperature may rise to 100 ° C. or higher (for example, 120 to 140 ° C.), and the idling operation may be continued at the top of the uphill.

  The corrected idle speed is sufficient if the hydraulic lash adjuster 4 is supplied with a sufficient oil pressure and oil amount to compensate for the increase in leak-down that occurs in the hydraulic lash adjuster 4 due to the high oil temperature. The number of revolutions is set to about 10 to 20% higher than the number.

  Increasing the idling speed increases the amount of air passing through the intake valve 6 by increasing the opening of the electronically controlled throttle valve 52, or the operating angle of the intake valve 6 by the lift / operating angle variable mechanism 1. The process is executed by increasing the amount of air passing through the intake valve 6. Further, the idling speed may be increased by advancing the ignition timing by the spark plug 51. The idle speed is controlled to be close to the target corrected idle speed by PI control.

  Therefore, when the variation in lift characteristics between cylinders due to the clearance is large, the amount of leak down of the hydraulic lash adjuster 4 is reduced by increasing the idling speed, and the variation in lift characteristics between the cylinders is suppressed to reduce engine vibration. This can reduce fuel consumption and exhaust emissions. In addition, since the increase in the idle speed relatively shortens the pressing operation period to the valve rocker arm 27 by the lift / operating angle variable mechanism 1, the leak down amount of the hydraulic lash adjuster 4 is reduced also in this respect. Will be.

  In the above embodiment, as the variable valve operating apparatus, the rocker arm 27 is provided and the hydraulic lash adjuster 4 is disposed at the portion constituting the fulcrum, but although not shown, the rocker arm 27 is not provided. This is a direct acting type in which the intake valve 6 is pushed and opened directly by the lift / operating angle variable mechanism 1, and a hydraulic lash adjuster is disposed between the intake valve 6 and the lift / operating angle variable mechanism 1. There may be.

  Moreover, although what provided the phase variable mechanism 2 was demonstrated as a variable valve apparatus, you may not provide the phase variable mechanism 2. FIG.

  In the present embodiment, the following effects can be achieved.

  (A) The lift / operating angle variable mechanism 1, the cylinder body 30, and the cylinder body 30 that can continuously change the lift characteristics corresponding to at least one of the valve lift amount and the operating angle of the intake valves 6 of the plurality of cylinders. A slidably built-in plunger 31 that forms an urging force from the cylinder body 30 by the elastic means 36D and forms a high-pressure chamber 33 that contains the lubricating oil, and hydraulic oil is introduced when the plunger 31 expands the high-pressure chamber 33. And a valve 36 for preventing hydraulic oil from flowing out of the high pressure chamber 33 when the high pressure chamber 33 is compressed, and transmitting the operation of the lift / operating angle variable mechanism 1 to the intake valve 6 of each cylinder. A hydraulic lash adjuster 4 interposed in the system, and the temperature of the lubricating oil supplied to the hydraulic lash adjuster 4 under an operating state in which the lift characteristic is controlled to a predetermined small set value. And an engine controller 5 serving as a control means for increasing the engine speed by increasing the set speed when the engine temperature exceeds a preset temperature, a hydraulic lash adjuster is provided in a low oil temperature region with a low frequency. 4 can be reduced, the variation in lift characteristics between cylinders can be suppressed, engine vibration can be reduced, and fuel efficiency and exhaust emission can be improved.

  (A) The transmission system for transmitting the operation of the lift / operating angle variable mechanism 1 to the intake valve 6 of each cylinder uses the rocker arm 27 oscillated by the lift / operating angle variable mechanism 1 to control the intake valve 6 of each cylinder. The hydraulic lash adjuster 4 is configured to open and close, and is arranged to support the fulcrum of the rocker arm 27. Therefore, the function of minimizing the clearance of the valve mechanism is increased by the action of the lever of the rocker arm 27. Can do.

  (C) Increasing the engine speed by the engine controller 5 as the control means increases the opening of the throttle valve 52, increases the operating angle of the lift / operating angle variable mechanism 1, or advances the ignition timing. To be executed. The engine speed is brought close to the target speed corrected by the PI control.

  (D) The lift / operating angle variable mechanism 1 is rotatably supported by a cam bracket and rotates in synchronization with the rotation of the engine. The drive shaft 10 includes a drive cam 11 on the outer periphery, and the drive cam 11 is a shaft. A swing cam 14 that is swingably arranged at different directional positions and presses the valve of the engine by swinging to open and close, and a link arm 15 through which the drive cam 11 formed on the drive shaft 10 is inserted. A link rod 16 connected to one end of the swing cam 14, a main shaft 12A rotatably supported by the cam bracket and controlled to rotate by an actuator 23, an eccentric shaft 12B eccentric from the main shaft 12A, A crank-shaped control shaft 12 composed of a web 12C connecting the main shaft 12A and the eccentric shaft 12B, and the eccentric shaft 12B are swingably provided. The end of the arm 15 is pivotably linked, and the end of the link rod 16 is pivotally linked to the other swinging end that is different in the axial position from the one end. And a swing arm 13 for transmitting the driving force of the drive cam 11 to the swing cam 14. The variable lift / operating angle mechanism 1 can increase the intermediate operating angle / lift, improve the medium speed torque, reduce the amount of change in the valve opening timing (IVO), and reduce the piston recess. .

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of the variable valve apparatus of the internal combustion engine which shows one Embodiment of this invention. Sectional drawing of a variable valve apparatus similarly. Sectional drawing which shows the supply path | route of the hydraulic lash adjuster and lubricating oil which are used for a variable valve apparatus. The flowchart which shows the flow of control which concerns on this embodiment.

Explanation of symbols

1 Lift / Operating Angle Variable Mechanism 2 Phase Variable Mechanism 3 Rocker Arm Mechanism 4 Hydraulic Rush Adjuster 5 Engine Controller 6 Intake Valve 10 Drive Shaft 11 Drive Cam 12 Control Shaft 13 Swing Arm 14 Swing Cam 15 Link Arm 16 Link Rod 27 Rocker Arm

Claims (6)

A variable lift / operating angle mechanism capable of continuously changing a lift characteristic corresponding to at least one of a valve lift amount and an operating angle of an intake valve of a plurality of cylinders;
Cylinder body, slidably incorporated in the cylinder body, extended from the cylinder body by elastic means, and a plunger that forms a high-pressure chamber for containing lubricating oil, and hydraulic oil is introduced when the plunger expands the high-pressure chamber And a valve that prevents hydraulic oil from flowing out of the high pressure chamber when the high pressure chamber is compressed, and is provided in a transmission system that transmits the operation of the lift / operating angle variable mechanism to the intake valve of each cylinder. Hydraulic lash adjuster,
A temperature sensor for detecting the temperature of the lubricating oil supplied to the hydraulic lash adjuster;
When the oil temperature detected by the temperature sensor exceeds a preset temperature under an operating state in which the lift characteristic is controlled to a predetermined small set value, the engine speed is corrected by increasing the set speed. A variable valve operating apparatus for an internal combustion engine. A transmission system for transmitting the operation of the lift / operating angle variable mechanism to the intake valve of each cylinder is configured to open / close the intake valve of each cylinder via a rocker arm that swings by the lift / operating angle variable mechanism,
2. The variable valve operating apparatus for an internal combustion engine according to claim 1, wherein the hydraulic lash adjuster is arranged to support a fulcrum of the rocker arm. It has a throttle valve that opens and closes the intake passage,
The variable valve operating apparatus for an internal combustion engine according to claim 1 or 2, wherein the control means increases the engine speed by increasing the opening of the throttle valve.   3. The variable valve operating system for an internal combustion engine according to claim 1, wherein the control unit increases an operating angle of the lift / operating angle variable mechanism to increase an engine speed. 4.   3. The variable valve operating apparatus for an internal combustion engine according to claim 1, wherein the control unit is capable of controlling an ignition timing, and increases the engine speed by advancing the ignition timing. .   The variable lift / operating angle mechanism is rotatably supported by a cam bracket and rotates in synchronization with the rotation of the engine. A drive shaft provided with a drive cam on the outer periphery and the drive cam have different axial positions. A swing cam that is swingably arranged and presses the valve of the engine by swinging to open and close, a link arm that passes through the drive cam formed on the drive shaft, and one end connected to the swing cam A link rod, a main shaft rotatably supported by the cam bracket and controlled to rotate by an actuator, an eccentric shaft that is eccentric from the main shaft, and a web that connects the main shaft and the eccentric shaft. The control shaft and the eccentric shaft are swingably provided, and one end of the link arm is pivotally linked to one swing end, and the axial end position is different from the one end. The other 2. An oscillating arm, wherein an end of the link rod is pivotally linked to a moving end, and a oscillating arm that transmits a driving force of the driving cam to the oscillating cam by an oscillating action. The variable valve operating apparatus for an internal combustion engine according to any one of claims 1 to 5.

Images