JP4803251B2 - Valve timing adjusting device for internal combustion engine - Google Patents

Description

The present invention relates to a valve timing adjusting device for an internal combustion engine capable of continuously and variably controlling the opening / closing timing of an intake or exhaust valve driven by a camshaft of an internal combustion engine (hereinafter also referred to as an engine) . In particular, the present invention relates to a vane-type continuously variable valve timing system using hydraulic pressure.

  Conventionally, a camshaft is driven via a timing pulley or chain sprocket that rotates in synchronization with the crankshaft of the internal combustion engine, and intake or exhaust of the internal combustion engine is caused by a phase difference due to the relative rotation of the timing pulley or chain sprocket and the camshaft. There is a vane type continuously variable valve timing system that continuously and variably controls the phase of valve opening and closing timing. In such a vane type continuously variable valve timing system, a hydraulic servo system such as an advance hydraulic chamber and a retard hydraulic chamber is provided on the inner peripheral wall of the timing pulley, and the vane rotor that rotates integrally with the camshaft is advanced hydraulically. The phase of the opening / closing timing of the intake or exhaust valve is changed by rotating to the angle side or the retard side.

  As a conventional technique, after turning off the ignition switch, the camshaft phase is advanced beyond the intermediate lock phase, and then the camshaft phase is adjusted by retarding the camshaft phase. After estimating the time until it fixes to an intermediate | middle lock phase, turning off an ignition switch, after moving an internal combustion engine until the estimated time passes, there exists a thing which stops an internal combustion engine (refer patent document 1). Here, when the phase of the camshaft is advanced from the intermediate lock phase, the drive reaction force from the intake valve or the OCV (oil control valve) is controlled to control the camshaft to a suitable position at the time of engine start. .

However, in the conventional technology, the viscosity of the oil is high at low oil temperature, so the drive shaft force from the intake valve alone may not return the camshaft phase to the intermediate lock phase after the internal combustion engine stops. There is. In addition, when the control is performed by estimating the time required for the advance angle and the retard angle, the oil viscosity is low and the amount of leakage increases at high oil temperatures. The hydraulic pressure supplied to and discharged from is greatly reduced. There is a possibility that the delay time becomes significantly longer when the hydraulic pressure is lowered.
Japanese Patent No. 29682604

  An object of the present invention is to provide a valve timing adjusting device for an internal combustion engine that can reliably fix the phase of a camshaft with respect to a timing rotor to a desired intermediate lock phase before or at the time of engine startup.

According to the first aspect of the present invention , the hydraulic pressure supply / discharge means for supplying and discharging the hydraulic pressure generated by the hydraulic pressure source relative to the advance hydraulic chamber and the retard hydraulic chamber during engine operation is connected to the hydraulic source. Provided with an oil supply path, an advance hydraulic chamber and an retard hydraulic chamber, and an oil discharge path for draining the oil. When the engine is stalled, the advance hydraulic chamber and the retard hydraulic chamber It is characterized by a drain mode in which oil is drained simultaneously. Further, the advance angle assist for causing the timing rotor to advance the camshaft phase beyond the intermediate lock phase to the continuously variable valve timing mechanism including the vane rotor, the advance hydraulic chamber, the retard hydraulic chamber, and the phase fixing means. Provide a spring. As a result, when the engine is started next time, oil has escaped from the advance hydraulic chamber, so the camshaft moves to the advance side due to the negative torque when it gets over the tappet. It moves to the retard side by force and is locked at the intermediate lock phase by the phase fixing means. Therefore, the camshaft phase with respect to the timing rotor can be reliably fixed to the intermediate lock phase during cranking of the internal combustion engine.

  According to the second aspect of the present invention, by providing an oil passage switching valve such as a pilot valve or a solenoid valve, when the engine is stopped, the engine is started, or the engine is stalled, it is advanced from the hydraulic source through the hydraulic supply / discharge means. The oil passage connected to the hydraulic chamber is switched to the oil passage from which the oil is drained from the advance hydraulic chamber. As a result, the oil passage from which the oil is drained from the advance hydraulic chamber is hardly affected by the hydraulic pressure from the hydraulic source, so that the oil in the advance hydraulic chamber is reliably discharged and locked at the intermediate lock phase. Becomes easy.

  According to the third aspect of the present invention, the hydraulic pressure source for supplying the hydraulic pressure to the advance hydraulic chamber and the retard hydraulic chamber is driven to rotate in synchronization with the crankshaft of the internal combustion engine so that the engine speed is increased. An oil pump that generates a proportional discharge amount is used. As a result, when the engine speed is low, the amount of oil discharged from the oil pump is reduced. Therefore, especially at high oil temperatures, the amount of leakage due to a decrease in the viscosity of the oil causes an increase in the advance hydraulic chamber and the delay time. The hydraulic pressure supplied to and discharged from the corner hydraulic chamber is reduced.

[Configuration of Reference Example 1]
FIGS. 1 to 7 show Reference Example 1 of the present invention. FIG. 1 is a diagram showing the overall configuration of a continuously variable valve timing adjusting device. FIGS. 2 and 3 show an intake continuously variable valve timing mechanism. 4 is a view showing a stopper pin driving mechanism, and FIG. 5 is a view showing a hydraulic control device including an ECU.

  This reference example shows the opening / closing timing of an intake valve (not shown) provided in a cylinder head 17 of a four-cycle reciprocating engine (internal combustion engine), for example, a DOHC (double overhead camshaft) engine (hereinafter referred to as engine). This is a continuously variable valve timing adjusting device capable of continuously variably controlling the phase (valve timing).

  The continuously variable valve timing adjusting device includes a timing rotor 1 that is rotationally driven by an engine crankshaft (not shown), and an intake side camshaft (hereinafter referred to as a camshaft) that is provided to be rotatable relative to the timing rotor 1. (Abbreviated) 2, a vane-type intake continuously variable valve timing mechanism 4 having a vane rotor 3 fixed to the end of the camshaft 2 and rotatably accommodated in the timing rotor 1, and a camshaft 2 for the timing rotor 1 And a hydraulic circuit (described later) having an advance / retard angle hydraulic control valve (OCV) 5 for rotating the phase of the vane rotor 3 forward and backward by hydraulic pressure, and a control mode (spool position) of the advance / retard hydraulic control valve 5 are electronically controlled. The engine control device (hereinafter referred to as ECU) 8 is a hydraulic control means.

  The timing rotor 1 includes a substantially annular plate-shaped chain sprocket 11 that is rotationally driven by a crankshaft of an engine via a timing chain 10, and one of the intake continuously variable valve timing mechanisms 4 disposed on the front end surface of the chain sprocket 11. It consists of a substantially cylindrical shoe housing 12 constituting parts and three small-diameter bolts 13 for fastening the chain sprocket 11 and the shoe housing 12 together. On the outer peripheral portion of the chain sprocket 11, a large number of tooth-shaped portions 14 that mesh with a large number of tooth-shaped portions (not shown) formed on the inner peripheral side of the timing chain 10 are formed. A female screw hole for fastening three small-diameter bolts 13 is formed in the ring plate portion of the chain sprocket 11 (which constitutes the rear cover portion of the shoe housing 12).

  The shoe housing 12 includes a cylindrical housing portion that rotatably houses the vane rotor 3 and an annular plate-like front cover portion that covers the front end side in the axial direction of the housing portion. A plurality of (three in this example) trapezoidal shoes (partition walls) 16 facing each other in the circumferential direction are provided in the housing portion of the shoe housing 12 so as to protrude toward the inner peripheral side. Each facing surface of these shoes 16 is formed in a circular arc shape in cross section, and a fan-shaped space portion is formed in a circumferential gap between two adjacent shoes 16. The plurality of shoes 16 are formed with bolt insertion holes for inserting the three small diameter bolts 13.

  The camshaft 2 is arranged in the cylinder head 17 of the engine, and is connected to drive so that it rotates once when the crankshaft of the engine rotates twice, and a cam crest for determining the opening / closing timing (valve timing) of the engine intake valve. Are connected to the vane rotor 3 together with the journal bearing 20 by a large-diameter bolt 19. A female screw hole for fastening the large-diameter bolt 19 is formed in the axial center portion of one end portion of the camshaft 2. The intake valve and the exhaust valve are pushed and opened by the cam crest of the camshaft 2, but the intake valve and the exhaust valve are closed by the spring force of the valve spring.

  The vane rotor 3 of the continuously variable intake valve timing mechanism 4 includes a plurality of (this example) projecting radially outward from the outer peripheral wall of the annular plate-like base portion having a female screw hole for fastening the large-diameter bolt 19. 3) vanes 23, and journal bearings 20 for rotatably supporting the inner peripheral side of the front cover portion of the shoe housing 12. In the vane rotor 3, a minute clearance is provided between the outer peripheral walls of the plurality of vanes 23 and the inner peripheral wall of the housing portion of the shoe housing 12. For this reason, the camshaft 2 and the vane rotor 3 can be rotated relative to the chain sprocket 11 and the shoe housing 12 (for example, a crank angle of 40 ° CA to 60 ° CA).

  The vane rotor 3 having the vanes 23, together with the shoe housing 12, constitutes a vane type hydraulic actuator that continuously varies the phase of the opening / closing timing of the intake valve of the engine using hydraulic pressure. The vanes 23 of the vane rotor 3 are substantially fan-shaped blades facing each other in the circumferential direction, and are disposed so as to protrude into a fan-shaped space formed in the circumferential gap between two adjacent shoes 16. Yes. An advance hydraulic chamber (hereinafter abbreviated as an advance chamber) is provided between the opposing surfaces of two adjacent shoes 16 and both side surfaces in the circumferential direction of the vane 23 fitted in the fan-shaped space portion formed by them. 24 and a retard hydraulic chamber (hereinafter abbreviated as a retard chamber) 25 are formed.

  That is, the fan-shaped space formed by the two shoes 16 adjacent to each vane 23 is oil-tightly divided into two hydraulic chambers, so that the advance chambers 24 and the delay chambers 24 are provided on both sides of each vane 23 in the circumferential direction. A corner chamber 25 is formed. A plurality of seal members 26 are mounted between the outer peripheral wall of the vane 23 of the vane rotor 3 and the housing portion of the shoe housing 12, and the outer peripheral wall of the base portion of the vane rotor 3 and each shoe 16 of the shoe housing 12 are attached. A plurality of seal members 27 are mounted between the inner peripheral wall.

  The hydraulic circuit supplies a hydraulic pressure to each advance chamber 24 of the intake continuously variable valve timing mechanism 4 and also supplies a first oil supply path (advance chamber side oil for draining oil in each advance chamber 24). The first oil passage) 21 and the second oil supply passage for draining the oil in each retard chamber 25 while supplying hydraulic pressure to each retard chamber 25 of the intake continuously variable valve timing mechanism 4. (Retarding chamber side oil passage, second oil passage) 22 is provided.

  The first and second oil supply paths 21 and 22 are formed in the cylinder head 17 of the engine. The first and second oil supply paths 21 and 22 are connected to the oil supply path 29 on the oil pump 6 side and the first and second oil supply paths 21 and 22, respectively. Two oil discharge passages (drain oil passages) 41 and 42 are connected to each other via an advance / retard angle hydraulic control valve (oil control valve: OCV) 5 for passage switching. Note that the first and second oil supply paths 21 a and 22 a formed in the camshaft 2 and the vane rotor 3 communicate with the first and second oil supply paths 21 and 22. The first oil discharge passage 41 is an advance chamber drain oil passage, and the second oil discharge passage 42 is a retard chamber drain oil passage.

  The oil supply passage 29 is provided with an oil pump (hydraulic power source) 6 for pumping up the oil in the oil pan 30 and discharging the oil to each part of the engine, and the first and second oil discharge passages 41, 42. Is connected to the oil pan 30. Here, the oil pump 6 is rotationally driven in synchronism with the crankshaft of the engine, and pressure-feeds an amount of oil proportional to the engine speed to each part of the engine.

  Here, a hydraulic chamber 31 formed in one of the three vanes 23 communicates with the advance chamber 24, and the inside of the valve body 32 is axially connected to the hydraulic chamber 31. A displacing hydraulic piston type stopper pin 33 (corresponding to the phase fixing means of the present invention) 33 is provided.

  The stopper pin 33 is fitted with a concave portion (fitting portion) 35 formed at a position corresponding to a desired intermediate lock phase of the front cover portion of the shoe housing 12 by applying a spring force from the spring 34. At this time, the vane rotor 3 is locked at the intermediate lock phase. Here, the desired intermediate lock phase refers to an intermediate phase (substantially intermediate lock phase) in the phase change width from the maximum retard angle phase to the maximum advance angle phase of the vane rotor 3. Allows starting.

  The hydraulic chamber 31 and the spring 34 constitute a stopper pin driving mechanism that drives the stopper pin 33 so as to be able to protrude and retract from the front end surfaces of the valve body 32 and the vane 23. Further, an oil passage 39 is provided between the hydraulic chamber 31 and the advance chamber 24, and the hydraulic chamber 31 and the advance chamber 24 communicate with each other when the vane rotor 3 has advanced beyond the intermediate lock phase. An oil passage 40 is also provided.

  Further, there is a gap between the convex portion 36 provided at the rear end portion of the vane rotor 3 of the intake continuously variable valve timing mechanism 4 and the annular concave portion 37 provided at the front end portion of the timing rotor 1 when the engine is stopped. An advance assist spring (advance side biasing means) 38 for advancing the phase of the camshaft 2 and the vane rotor 3 with respect to the timing rotor 1 to an intermediate lock phase or more even when the hydraulic pressure is reduced, such as when It has been.

  The ECU 8 detects the current operating state based on signals from the crank angle sensor 44 that detects the engine speed, the engine load sensor 45, and the air flow meter 46 that detects the intake air amount, and from the crank angle sensor 44 and the cam angle sensor. The relative rotational positions of the timing rotor 1 and the camshaft 2 and the vane rotor 3 and the intermediate lock phase of the camshaft 2 and the vane rotor 3 are detected by the above signals. The ECU 8 controls the control mode of the advance / retard hydraulic control valve 5 so that the opening / closing timing of the intake valve of the engine becomes an optimum value according to the engine speed and the engine load. Here, 47 is a cooling water temperature sensor for detecting the cooling water temperature of the engine or an oil temperature sensor for detecting the temperature of the oil. Reference numeral 48 denotes an ignition (IG) switch.

  The advance / retard hydraulic control valve 5 corresponds to the hydraulic supply / discharge means of the present invention. As shown in FIG. 3, the control valve 5a accommodated in a valve body (not shown) forming a hydraulic circuit, And an electromagnetic actuator 5b for driving the control valve 5a and relatively switching between the first and second oil supply passages 21, 22 and the oil supply passage 29 and the first and second oil discharge passages 41, 42. It is configured to be controllable and is switched by a control signal from the ECU 8.

  The control valve 5a includes a cylindrical sleeve 50 accommodated in a concave portion provided at a predetermined position of the valve body, a spool (spool valve) 51 slidably accommodated in the sleeve 50, and the spool. And a spring 52 for urging 51 to the initial position (the electromagnetic actuator 5b side). Of these, the sleeve 50 is formed with an oil supply port 53 connected to the oil supply path 29 on the oil pump 6 side.

  Furthermore, a first drain port 55 for draining oil in the advance chamber 24, a second drain port 56 for draining oil in the retard chamber 25, and the first and second oil supply paths 21, 22 The first and second oil supply / discharge ports 57, 58 and the like connected to are formed. The outer periphery of the spool 51 is provided with four first to fourth land portions that form three oil passages from the illustrated left end portion in the axial direction toward the illustrated right end portion.

  The electromagnetic actuator 5b includes a cylindrical yoke 61 fixed to the right end in the figure of the sleeve 50 of the control valve 5a, a coil bobbin 62 disposed on the inner peripheral side of the yoke 61, and a coil bobbin 62 wound around the outer periphery of the coil bobbin 62. And a solenoid coil 63 mounted thereon. Furthermore, it is composed of a stator core (fixed iron core) 64 and a moving core (movable iron core) 65 disposed on the inner peripheral side of the coil bobbin 62, and a solenoid shaft 66 that operates integrally with the moving core 65.

  The illustrated left end portion of the solenoid shaft 66 of the electromagnetic actuator 5b is in contact with the illustrated right end surface of the spool 51 of the control valve 5a. Thereby, the spool 51 of the control valve 5a is reciprocally displaced in the axial direction integrally with the moving core 65 and the solenoid shaft 66. The coil bobbin 62 is a primary resin molded product formed integrally with a resin in a substantially cylindrical shape.

  In addition, the solenoid coil 63 and the in-vehicle power source are electrically connected to a portion of the resin molded member (resin secondary molded product) 67 formed on the outer periphery of the solenoid coil 63 and exposed to the outside of the yoke 61. A connector portion 5c in which a terminal (external connection terminal) 68 is insert-molded is integrally formed. The solenoid coil 63 is supplied with a drive current mainly from the ECU 8 during engine operation to generate a magnetomotive force, and the moving core 65 is attracted in accordance with the magnetomotive force.

  Therefore, during the advance angle control by the ECU 8, a drive current is supplied from the ECU 8, and the moving core 65 and the spool 51 of the control valve 5a are attracted to a predetermined position against the spring force of the spring 52. At this time, an intermediate oil passage provided in the outer peripheral portion of the spool 51 of the control valve 5a communicates the oil supply passage 29 and the first oil supply passage 21, and an oil passage at the right end in the drawing provided in the outer peripheral portion of the spool 51. Communicates with the second oil supply path 22 and the second oil discharge path 42. As a result, during advance control, oil is introduced into the advance chamber 24 and drained from the retard chamber 25.

  Further, during the retard control by the ECU 8, a drive current is supplied from the ECU 8, and the moving core 65 and the spool 51 of the control valve 5a are attracted to a predetermined position against the spring force of the spring 52. At this time, an intermediate oil passage provided in the outer peripheral portion of the spool 51 of the control valve 5a communicates the first oil supply passage 21 and the first oil discharge passage 41, and at the right end of the drawing provided in the outer peripheral portion of the spool 51. The oil passage communicates the second oil supply passage 22 and the oil supply passage 29. Thereby, at the time of retard control, oil is drained from the advance chamber 24 and the oil is introduced into the retard chamber 25.

In the drain mode by the ECU 8, a driving current is supplied from the ECU 8, and the moving core 65 and the spool 51 of the control valve 5a are attracted to a predetermined position against the spring force of the spring 52. At this time, an intermediate oil passage provided in the outer peripheral portion of the spool 51 of the control valve 5a communicates the oil supply passage 29 and the first oil supply passage 21, and at the same time, an oil passage at the left end shown in the outer periphery of the spool 51. There communicating with the first oil supply passage 21 and the first oil discharge passage 41. Further, an oil passage at the right end of the figure provided in the outer peripheral portion of the spool 51 of the control valve 5 a communicates the second oil supply passage 22 and the second oil discharge passage 42. Thereby, oil is drained from the advance chamber 24 and the retard chamber 25 in the drain mode.

[Features of Reference Example 1]
Next, the operation of the stopper pin 33 of this reference example will be briefly described with reference to FIGS. Here, FIG. 6A to FIG. 6C are views showing the operating state of the stopper pin.

  When the advance angle control is performed by the ECU 8 when the engine is stopped, the oil is introduced into the advance chamber 24 and the oil in the retard chamber 25 is drained to enter the advance chamber 24 and the oil passages 39 and 40. Hydraulic pressure is supplied. As a result, the upper and lower hydraulic pressures of the hook-shaped portion 33a provided on the outer periphery of the stopper pin 33 in the hydraulic chamber 31 are balanced, so that the stopper pin is driven by the spring force of the spring 34 as shown in FIG. The leading portion of 33 protrudes from the front end surface of the vane 23 and comes into contact with the front cover portion of the shoe housing 12 (first-stage fitting).

  Thereafter, when the ECU 8 confirms that the phase of the vane rotor 3 has advanced beyond the intermediate lock phase by signals from the crank angle sensor 44 and the cam angle sensor, the ECU 8 performs the drain mode. As a result, the oil in the advance chamber 24 and the first oil supply passage 21 is drained, so that the phase of the vane rotor 3 is retarded as shown in FIG. Move to.

  When the vane rotor 3 is retarded to the intermediate lock phase, as shown in FIG. 6C, a concave portion formed in the shoe housing 12 at the leading end of the stopper pin 33 to which the spring force of the spring 34 is applied. (Fitting part) 35 is fitted (second-stage fitting). That is, when the leading portion of the stopper pin 33 is fitted into the concave portion 35, the camshaft 2 and the vane rotor 3 are fixed to the intermediate lock phase, so that the engine can be started at the intermediate lock phase.

  Next, the operation of the continuously variable valve timing adjusting apparatus of this reference example will be briefly described with reference to FIGS. Here, FIG. 7 is a flowchart showing control for locking to the intermediate lock phase when the engine is stopped.

  First, when the ignition (IG) switch 48 is turned on, the routine of FIG. 7 is started. Then, it is determined whether or not the ignition (IG) switch 48 is turned off (step S11). If this determination is NO, the process returns.

  When the determination result in step S11 is YES, the control mode of the advance / retard hydraulic control valve 5 is set to the phase of the intake continuously variable valve timing mechanism 4, that is, the camshaft 2 and the vane rotor 3 with respect to the timing rotor 1. The mode is changed to an advance angle control mode for advancing the phase (step S12).

  In the advance angle control mode, the spool 51 of the advance / retard angle hydraulic control valve 5 is displaced so that the oil supply path 29 on the oil pump 6 side communicates with the first oil supply path 21 on the advance angle chamber 24 side, and By connecting the second oil discharge passage 42 on the oil pan 30 side and the second oil supply passage 22 on the retard chamber 25 side, the oil is introduced into the advance chamber 24 and the oil in the retard chamber 25 is removed. Drain.

  Next, it is determined whether or not the phases of the camshaft 2 and the vane rotor 3 have advanced with respect to the timing rotor 1 more than the intermediate lock phase (step S13). When this determination result is NO, the processing from step S11 or step S12 is repeated.

  If the determination result in step S13 is YES, that is, if the advance angle is equal to or greater than the intermediate lock phase, the hydraulic pressure in the advance chamber 24 and the retard chamber 25 is maintained. Alternatively, the control mode of the advance / retard hydraulic control valve 5 is maintained in the advance angle control mode in which the phase of the intake continuously variable valve timing mechanism 4, that is, the phase of the camshaft 2 and the vane rotor 3 is advanced with respect to the timing rotor 1 ( Step S14).

  In the advance angle control mode, the spool 51 of the advance / retard angle hydraulic control valve 5 is displaced so that the oil supply path 29 on the oil pump 6 side communicates with the first oil supply path 21 on the advance angle chamber 24 side, and By connecting the second oil discharge passage 42 on the oil pan 30 side and the second oil supply passage 22 on the retard chamber 25 side, the oil is introduced into the advance chamber 24 and the oil in the retard chamber 25 is removed. Drain.

  Next, it is determined whether or not the engine speed is equal to or lower than a predetermined speed (for example, 300 rpm) (step S15). If this determination result is NO, the processes in and after step S14 are repeated. If the determination result in step S15 is YES, the control mode of the advance / retard hydraulic control valve 5 is changed to a drain mode in which the oil in the advance chamber 24 and the retard chamber 25 is drained (step S16). ). Thereafter, this control is terminated.

  In this drain mode, the spool 51 of the advance / retard hydraulic control valve 5 is displaced, the first oil discharge passage 41 on the oil pan 30 side communicates with the first oil supply passage 21 on the advance chamber 24 side, and The oil in the advance chamber 24 and the retard chamber 25 is drained by connecting the second oil discharge passage 42 on the oil pan 30 side and the second oil supply passage 22 on the retard chamber 25 side.

  As described above, in the continuously variable valve timing adjusting device of the present reference example, the advance angle control is performed after the ignition (IG) switch 48 is turned off, and it is confirmed that the advance angle is greater than the intermediate lock phase. When the engine speed becomes equal to or lower than a predetermined speed, the ECU 8 determines that the oil pump 6 is stopped and the hydraulic pressure in the advance chamber 24 has decreased to a predetermined value or less, and the control of the advance / retard hydraulic control valve 5 is performed. The mode is changed to the drain mode, and the oil in the advance chamber 24, the retard chamber 25, and the first and second oil supply passages 21 and 22 is drained.

  Accordingly, the advance chamber 24 and the first oil supply passage 21 are completely drained, and the retard chamber 25 and the second oil supply passage 22 are completely drained, so that the timing rotor is driven by the driving reaction force of the intake valve. 1, the phase of the camshaft 2 and the vane rotor 3 moves to the retard side. When the phases of the camshaft 2 and the vane rotor 3 are retarded to the intermediate lock phase, they are locked (fixed) by the stopper pins 33 as shown in FIG.

  That is, the stopper pin 33 that operates when the advance chamber 24 is drained is engaged with the concave portion 35 of the shoe housing 12 against the spring force from the spring 34, so that the camshaft 2 and the vane rotor 3 are in the intermediate lock position. Locked to. Note that the advance angle control may use delay control.

  Therefore, in the continuously variable valve timing adjusting device of the present reference example, even when the oil viscosity is high as at low oil temperature and it cannot be returned to the intermediate lock position in a predetermined estimated time, before starting the engine, The phase of the camshaft 2 with respect to the timing rotor 1 can be reliably fixed to the intermediate lock phase.

[Reference Example 2]
FIG. 8 shows a reference example 2 of the present invention, and is a flowchart showing a control for locking to an intermediate lock phase when the engine is started.

  First, it is determined whether or not the ignition (IG) switch 48 is turned on (step S21). If this determination is NO, the process returns. If the determination result in step S21 is YES, the control mode of the advance / retard hydraulic control valve 5 is changed to a drain mode in which oil in the advance chamber 24 and the retard chamber 25 is drained (step S22). ).

  In this drain mode, the spool 51 of the advance / retard hydraulic control valve 5 is displaced, the first oil discharge passage 41 on the oil pan 30 side communicates with the first oil supply passage 21 on the advance chamber 24 side, and The oil in the advance chamber 24 and the retard chamber 25 is drained by connecting the second oil discharge passage 42 on the oil pan 30 side and the second oil supply passage 22 on the retard chamber 25 side.

  Next, it is determined whether or not the engine start mode has ended (step S23). If this determination result is NO, the processes in and after step S22 are repeated. If the determination result in step S23 is YES, lock fixing control for locking to the intermediate lock phase is performed (step S24). Thereafter, this control is terminated.

  As described above, in the continuously variable valve timing adjusting device of this reference example, when the engine is stopped, the phase of the intake continuously variable valve timing mechanism 4, that is, the phase of the camshaft 2 and the vane rotor 3 is stopped on the advance side from the intermediate lock phase. is doing. For this reason, when the ECU 8 determines that the ignition (IG) switch 48 is turned on (when the engine is started), the control mode of the advance / retard hydraulic control valve 5 is changed to the drain mode, and the advance chamber 24, retard The oil in the chamber 25 and the first and second oil supply passages 21 and 22 are drained.

  Thereby, the phase of the camshaft 2 and the vane rotor 3 moves to the retard side with respect to the timing rotor 1 due to the driving reaction force from the intake valve during cranking of the engine. When the phase of the camshaft 2 and the vane rotor 3 is retarded to the intermediate lock phase, the camshaft 2 and the vane rotor 3 are locked (fixed) by the stopper pin 33.

  Then, when the engine start mode is exited, lock fixing control for securely fixing the stopper pin 33 is performed. Therefore, in the continuously variable valve timing adjusting device of this reference example, the phase of the camshaft 2 with respect to the timing rotor 1 can be reliably fixed to the intermediate lock phase when the engine is started.

[Example 1]
FIG. 9 shows the first embodiment of the present invention, and is a flowchart showing the control for locking to the intermediate lock phase when the engine is stalled.

  First, when the ignition (IG) switch 48 is turned on, the routine of FIG. 9 is started. Then, it is determined whether or not the engine speed has fallen below a predetermined speed (step S31). If this determination is NO, the process returns.

  If the determination result in step S31 is YES, the control mode of the advance / retard hydraulic control valve 5 is changed to a drain mode in which the oil in the advance chamber 24 and the retard chamber 25 is drained (step S32). ). Thereafter, this control is terminated.

  In this drain mode, the spool 51 of the advance / retard hydraulic control valve 5 is displaced, the first oil discharge passage 41 on the oil pan 30 side communicates with the first oil supply passage 21 on the advance chamber 24 side, and The oil in the advance chamber 24 and the retard chamber 25 is drained by connecting the second oil discharge passage 42 on the oil pan 30 side and the second oil supply passage 22 on the retard chamber 25 side.

  As described above, in the continuously variable valve timing adjusting apparatus of the present embodiment, when the ECU 8 performs engine stall (engine stall) determination, the control mode of the advance / retard hydraulic control valve 5 is changed to the drain mode, and the advance angle The oil in the chamber 24, the retard chamber 25, and the first and second oil supply passages 21 and 22 are drained.

  Accordingly, when the engine is started next time, the oil has escaped from the advance chamber 24 and the first oil supply passage 21 in the engine start mode, so that the advance assist spring 38 is incorporated in the intake continuously variable valve timing mechanism 4. Then, the phase of the camshaft 2 and the vane rotor 3 moves to the advance side with respect to the timing rotor 1 due to the negative torque when the cam crest of the camshaft 2 gets over the tappet.

  Next, due to the driving reaction force when the cam crest of the camshaft 2 rides on the tappet, the phase of the intake continuously variable valve timing mechanism 4, that is, the phase of the camshaft 2 and the vane rotor 3 is retarded with respect to the timing rotor 1. It can be moved and locked (fixed) by the stopper pin 33 at the intermediate lock phase.

[Reference Example 3]
FIG. 10 shows Reference Example 3 of the present invention, and is a flowchart showing control for locking to the intermediate lock phase when the oil temperature is high (when the oil pressure is lowered).

  First, when the ignition (IG) switch 48 is turned on, the routine of FIG. 10 is started. Then, it is determined whether or not the ignition (IG) switch 48 is turned off (step S41). If this determination is NO, the process returns.

  If the determination result in step S41 is YES, the oil temperature estimated from the cooling water temperature detected by the cooling water temperature sensor or the oil temperature detected by the oil temperature sensor is a high oil temperature (eg, 110 ° C. or higher). Is determined (step S42).

  When the determination result is NO, the control mode of the advance / retard hydraulic control valve 5 is set to advance the phase of the intake continuously variable valve timing mechanism 4, that is, the phase of the camshaft 2 and the vane rotor 3 with respect to the timing rotor 1. The advance angle control mode is changed (step S43). Thereafter, this control is terminated.

  In this advance angle control mode, the spool 51 of the advance / retard angle hydraulic control valve 5 is displaced so that the oil supply path 29 on the oil pump 6 side communicates with the first oil supply path 21 on the advance angle chamber 24 side, and By connecting the second oil discharge passage 42 on the oil pan 30 side and the second oil supply passage 22 on the retard chamber 25 side, the oil is introduced into the advance chamber 24 and the oil in the retard chamber 25 is removed. Drain.

  If the decision result in the step S42 is YES, the control mode of the advance / retard hydraulic control valve 5 is changed to a drain mode for draining the oil in the advance chamber 24 and the retard chamber 25 (step S44). ). Thereafter, this control is terminated.

  In this drain mode, the first oil discharge path 41 on the oil pan 30 side communicates with the first oil supply path 21 on the advance angle chamber 24 side, and the second oil discharge path 42 on the oil pan 30 side and the retard chamber The oil in the advance chamber 24 and the retard chamber 25 is drained by communicating with the second oil supply path 22 on the 25 side.

  As described above, in the continuously variable valve timing adjusting device of the present reference example, the camshaft 2 with respect to the phase of the intake continuously variable valve timing mechanism 4, that is, the timing rotor 1, when the oil pressure decreases, particularly when the oil temperature is high, when the engine is stopped. It is very difficult to advance the phase of the vane rotor 3.

  Therefore, when the ECU 8 determines that the temperature of the oil supplied into the advance chamber 24 is high (for example, 110 ° C. or higher), the control mode of the advance / retard hydraulic control valve 5 is drained when the engine is stopped. The mode is changed, and the oil in the advance chamber 24, the retard chamber 25, and the first and second oil supply passages 21 and 22 is drained. Accordingly, when the engine is started next time, the oil has escaped from the advance chamber 24 and the first oil supply passage 21 in the same manner as described above, so that it can be locked (fixed) at the intermediate lock phase when the engine is cranked. .

[Configuration of Reference Example 4]
11 and 12 show a reference example 4 of the present invention. FIG. 11 is a state diagram of the internal combustion engine valve timing adjustment device during operation of the engine. FIG. 12 is an engine stoppage of the internal combustion engine valve timing adjustment device. It is a state figure at the time of the drain mode at the time of an engine start.

  In the hydraulic circuit of the intake continuously variable valve timing mechanism 4 of this reference example, the first oil supply passage 21 that connects the first oil supply / discharge port 57 of the advance / retard hydraulic control valve 5 and the advance chamber 24 is provided in the middle of the hydraulic circuit. The pilot valve (corresponding to the oil passage switching valve of the present invention) 7 is connected. In this reference example, the pilot valve 7 is provided between the advance / retard hydraulic control valve 5 and the advance chamber 24, that is, in the middle of the first oil supply path 21, but in the middle of the first oil supply path 21. Instead of the pilot valve 7, an electromagnetic valve or the like may be provided.

  This advance / retard hydraulic control valve 5 includes a control valve 5a accommodated in a concave portion provided at a predetermined position of a valve body 49 forming a hydraulic system circuit, an electromagnetic actuator 5b for driving the control valve 5a, and the like. It is composed of

  Among these, in the sleeve 50, an oil supply port 53 connected to an oil supply path 29 on the oil pump (hydraulic power source) 6 side for pumping up oil in the oil pan 30 and discharging the oil to various parts of the engine, a pilot valve 7 Are connected to a first drain port 55 for draining oil in the hydraulic control chamber 73, a second drain port 56 for draining oil in the retard chamber 25, and the first and second oil supply paths 21 and 22. First and second oil supply / discharge ports 57 and 58, a communication port 59 connected to the hydraulic control chamber 73 of the pilot valve 7, and the like are formed.

  The illustrated left end portion of the solenoid shaft 66 of the electromagnetic actuator 5b is fitted into a shaft hole formed in the illustrated right end surface of the spool 51 of the control valve 5a. The solenoid coil 63 is supplied with a drive current from the ECU 8 during engine operation to generate a magnetomotive force, and the moving core 65 is attracted in accordance with the magnetomotive force. Further, in the drain mode, since the drive current is stopped from the ECU 8, the spool 51 of the control valve 5a is returned to the initial position by the spring force of the spring 52.

  The pilot valve 7 is provided to reinforce the drain mechanism more than the intake continuously variable valve timing mechanism 4 of FIGS. 1 to 3, and is a cylindrical sleeve accommodated in a predetermined portion of a valve body (not shown). 71, a spool (spool valve) 72 slidably accommodated in the sleeve 71, and a spring 74 that urges the spool 72 toward the hydraulic control chamber 73.

  Among these, the sleeve 71 drains the oil in the advance chamber 24 and the third oil supply / discharge port 75 connected to the third oil supply path 60 that connects the communication port 59 of the control valve 5a and the hydraulic control chamber 73. A third drain port 77 connected to the oil passage 76 and first oil supply / discharge ports 78 and 79 connected to the first oil supply passage 21 are formed. Two first and second land portions forming one oil passage are provided on the outer peripheral portion of the spool 72.

  Then, in the middle of the oil passage 90 connecting the oil supply passage 29 on the oil pump 6 side and the third oil supply passage 60 on the pilot valve 7 side, it occurs due to a change in the discharge amount of the oil pump 6 due to fluctuations in the engine speed. A fixed throttle 9 for absorbing pressure fluctuations in the oil passage 90 is provided.

  Further, in the hydraulic circuit of the continuously variable intake valve timing mechanism 4 of this reference example, an oil passage 76 for draining oil in the advance chamber 24 and a second oil supply passage 22 for draining oil from the retard chamber 25 are provided. And a check valve 93 that is provided in the middle of the communication path 92 and opens when the hydraulic pressure in the retard chamber 25 is lower than the hydraulic pressure in the advance chamber 24.

[Features of Reference Example 4]
Next, the operation of the continuously variable valve timing adjusting device of this reference example will be briefly described with reference to FIGS.

  As the engine starts, the oil pump 6 is driven to rotate by the engine. As a result, when the oil pressure in the oil supply passage 29, the oil passage 90, the third oil supply passage 60, and the hydraulic control chamber 73 rises and the oil pressure in the hydraulic control chamber 73 exceeds the spring force of the spring 74, FIG. As shown in FIG. 2, the spool 72 of the pilot valve 7 is displaced to the right in the figure.

  Further, the fixed throttle 9 provided in the middle of the oil passage 90 connecting the oil supply passage 29 on the oil pump 6 side and the third oil supply passage 60 on the pilot valve 7 side causes a change in the discharge amount of the oil pump 6. The spool 72 of the pilot valve 7 is surely on the right side of the figure by stably holding the oil pressure in the hydraulic control chamber 73 even when the pressure fluctuation is absorbed and the oil pressure is lowered or the pressure fluctuation is large. Kept in a state.

  On the other hand, when the spool 51 of the advance / retard hydraulic control valve 5 is changed to the drain mode when the engine is stopped or the engine is started, the hydraulic control chamber 73 on the left side of the pilot valve 7 in the drawing shows the spool 51 of the advance / retard hydraulic control valve 5. Is displaced to the left in the figure against the spring force of the spring 52, so that the oil in the advance chamber 24 and the retard chamber 25 is drained, and the oil in the hydraulic control chamber 73 is also drained. The spool 72 of the valve 7 moves to the left in the figure by the spring force of the spring 74.

  At this time, even if the oil pump 6 generates hydraulic pressure, the first oil supply path 21 that passes through the oil path of the advance / retard angle hydraulic control valve 5 and connects to the advance chamber 24 has the oil path of the pilot valve 7 as oil. By communicating with the passage 76, the hydraulic pressure from the oil pump 6 is completely cut off. Further, in the oil passage 90 from the oil pump 6 toward the hydraulic control chamber 73 of the pilot valve 7, the hydraulic pressure is reduced by the fixed throttle 9, so that the spool 72 is fixed on the left side in the drawing by the spring force of the spring 74 of the pilot valve 7. .

  Through the above operation, the oil passage 76 through which oil is drained from the advance chamber 24 of the intake continuously variable valve timing mechanism 4 is discharged to the intake continuously variable valve timing mechanism 4 of FIGS. 1 to 3 at the engine speed. Since it is hardly affected by the hydraulic pressure fluctuation (pressure fluctuation) from the oil pump 6 whose amount changes, the oil in the advance chamber 24 can be reliably discharged and locked (fixed) by the stopper pin 33 at the intermediate lock phase. It will be very easy.

  Further, a check valve 93 provided in the middle of a communication path 92 communicating between the oil passage 76 where oil is drained from the advance chamber 24 and the second oil supply passage 22 where oil is drained from the retard chamber 25. Is opened when the hydraulic pressure in the retard chamber 25 is smaller than the hydraulic pressure in the advance chamber 24, so that no negative pressure is generated in the retard chamber 25 and the vane rotor 3 is prevented from moving further toward the advance side. be able to.

[Other Examples]
In this embodiment, three shoes 16 are provided on the inner peripheral portion of the shoe housing 12, and three vanes 23 are provided on the outer peripheral portion of the vane rotor 3, so that three advance chambers (advance hydraulic chambers) 24 and Although the valve timing is continuously varied by providing three retarding chambers (retarding hydraulic chambers) 25, four or more shoes 16 are provided on the inner peripheral portion of the shoe housing 12, and four on the outer peripheral portion of the vane rotor 3. By providing the vanes 23 described above, four or more advance chambers (advance hydraulic chambers) 24 and four or more retard chambers (retard hydraulic chambers) 25 are provided to continuously vary the valve timing. Also good. Alternatively, two advance chambers (advance hydraulic chambers) 24 and two retard chambers (retard hydraulic chambers) 25 may be provided to continuously vary the valve timing.

  Here, when idling, the opening and closing timing of the intake valve of the engine is greatly delayed (retarded) to eliminate the overlap (the time when the intake valve and the exhaust valve are opened simultaneously) to stabilize the combustion. May be. Also, at medium speed and high load, the opening / closing timing of the intake valve is advanced (advanced) to increase the overlap, increase the self EGR (residual gas in the combustion chamber), lower the combustion temperature, and reduce HC, NOx The amount of discharge may be reduced. In this case, pump loss is reduced and fuel efficiency is improved. Further, at the time of high speed and high load, the closing timing of the intake valve may be delayed to an optimum position (retarded) to ensure the maximum output.

  Alternatively, the actual position of the camshaft 2 may be detected by a sensor, and the advance / retard hydraulic control valve 5 may be feedback-controlled so that the target valve timing is reached. In this embodiment, the valve timing is continuously variable. However, the valve timing may be variable in three stages, ie, an advance angle control mode, a retard angle control mode, and a drain mode, or in multiple stages. The present invention may be used not only for the intake continuous variable valve timing mechanism but also for the intake / exhaust continuous variable valve timing mechanism or the exhaust continuous variable valve timing mechanism. As the internal combustion engine, an overhead valve (OHV) engine or an overhead camshaft (OHC) engine may be used.

It is the schematic which showed the whole structure of the valve timing adjustment apparatus for internal combustion engines (reference example 1). It is the front view which showed the intake continuous variable valve timing mechanism (reference example 1). It is sectional drawing which showed the intake continuous variable valve timing mechanism (reference example 1). It is the schematic which showed the stopper pin drive mechanism (reference example 1). It is the block diagram which showed the hydraulic control apparatus containing ECU (reference example 1). (A)-(c) is explanatory drawing which showed the operation state of the stopper pin (reference example 1). It is the flowchart which showed the control locked to an intermediate | middle lock phase at the time of an engine stop (reference example 1). It is the flowchart which showed the control which locks to an intermediate | middle lock phase at the time of engine start (reference example 2). FIG. 5 is a flowchart illustrating control for locking to an intermediate lock phase when the engine is stalled (Example 1). FIG. It is the flowchart which showed the control which locks to an intermediate | middle lock phase at the time of high oil temperature (reference example 3). FIG. 6 is a state diagram during engine operation of a valve timing adjusting device for an internal combustion engine (Reference Example 4). FIG. 6 is a state diagram of the internal combustion engine valve timing adjustment device when the engine is stopped or when the engine is in the drain mode (Reference Example 4).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Timing rotor 2 Cam shaft 3 Vane rotor 4 Intake continuously variable valve timing mechanism 5 Advance / retard hydraulic control valve (hydraulic supply / discharge means)
6 Oil pump (hydraulic power source)
7 Pilot valve (oil switch valve)
8 ECU
9 Fixed throttle 21 First oil supply path (oil path)
22 Second oil supply path 24 Advance chamber (advance hydraulic chamber)
25 Retarded chamber (retarded hydraulic chamber)
29 Oil supply path 33 Stopper pin (phase fixing means)
38 Advance angle assist spring 92 Communication path 93 Check valve

Claims (3)

(A) a timing rotor that rotates in synchronization with a crankshaft of an internal combustion engine (hereinafter referred to as an engine) ;
(B) a camshaft having a cam crest for determining opening and closing timing of the intake or exhaust valve of the engine, and capable of relative rotational movement with the timing rotor;
(C) a vane rotor that rotates integrally with the camshaft;
(D) an advance hydraulic chamber for rotating the vane rotor by hydraulic pressure to advance the phase of the camshaft relative to the timing rotor;
(E) a retard hydraulic chamber for rotating the vane rotor by hydraulic pressure and retarding the phase of the camshaft relative to the timing rotor;
(F) phase fixing means for fixing the phase of the camshaft to a desired intermediate lock phase when the oil in the advance hydraulic chamber is drained;
(G) having an oil supply path connected to a hydraulic pressure source, an oil supply path connected to the advance hydraulic chamber and the retard hydraulic chamber, and an oil discharge path for draining oil during engine operation; And hydraulic supply / discharge means for supplying and discharging the hydraulic pressure generated by the hydraulic source relative to the advance hydraulic chamber and the retard hydraulic chamber,
In the continuously variable valve timing mechanism including the vane rotor, the advance hydraulic chamber, the retard hydraulic chamber, and the phase fixing means, the camshaft phase is advanced to the intermediate lock phase or more with respect to the timing rotor. An advance angle assist spring is provided to
The hydraulic supply / discharge means connects the advance hydraulic chamber and the retard hydraulic chamber to the oil discharge passage when the engine is stalled , and simultaneously drains oil in the advance hydraulic chamber and the retard hydraulic chamber. A valve timing adjusting device for an internal combustion engine characterized by performing a mode. The valve timing adjusting device for an internal combustion engine according to claim 1,
An internal combustion engine comprising an oil passage switching valve that switches from an oil passage that passes through the hydraulic pressure supply / discharge means and connects to the advance hydraulic chamber from the hydraulic pressure source to an oil passage that drains oil from the advance hydraulic chamber when the engine stalls Valve timing adjustment device for engines. The valve timing adjusting device for an internal combustion engine according to claim 1 or 2,
The hydraulic pressure source for supplying hydraulic pressure to the advance hydraulic chamber and the retard hydraulic chamber is an oil that is driven to rotate in synchronization with the crankshaft of the engine and generates a discharge amount proportional to the engine speed. A valve timing adjusting apparatus for an internal combustion engine, characterized by using a pump.

Images