JP2009264153A - Variable cam phase internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable cam phase internal combustion engine which realizes reduction in the manufacturing cost, inhibition of poor operation, and the like. <P>SOLUTION: A spool 39 has a bottomed cylindrical shape opening at a return spring 40 side and has an open end closed by a plug 90 to form a hollow part 91 therein. The spool 39 includes four supply holes 92 for introducing a working fluid from a supply port 81 to the hollow part 91; an OPA-side advancing group 93 that provides communication between a supply port 81 and an OPA-side advancing port 82 at an advancing position; four OPA-side retarding communication holes 94, providing communication between the hollow part 91 and an OPA-side retarding port 83 at a retarding position; a CTA-side group 95 providing communication between an advancing oil passage 55 and a center oil passage 57 at the advancing position and providing communication between the retarding oil passage 56 and the center oil passage 57 at the retarding position; and four orifices 96, providing communication between the hollow part 91 and the CTA-side group 95. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cam phase variable internal combustion engine equipped with a cam torque drive type valve timing control device, and more particularly to a technique for realizing reduction in manufacturing cost, suppression of malfunction, and the like.

  Many 4-cycle engines (hereinafter simply referred to as engines) are equipped with various variable valve mechanisms to improve output and fuel consumption, reduce harmful exhaust gas components, and the like. As a variable valve mechanism, there is a conventional one that switches between a low-speed cam and a high-speed cam, but the cam phase and valve lift are individually set to further improve the transient characteristics and reduce the throttle. In recent years, continuously variable control has become mainstream. As a valve timing control device (Variable Timing Control Device: hereinafter referred to as VTC) used for variable control of the cam phase, an oil pressure actuated phaser (Oil Pressure Actuated phaser: hereinafter referred to as OPA) is used. However, a cam torque driven variable phaser (Cam Torque Actuated phaser: hereinafter referred to as CTA) has been developed that is responsive and consumes less hydraulic oil (engine oil). (See Patent Documents 1 and 2).

The CTA includes a rotor that rotates integrally with the camshaft, a housing that rotates in synchronization with the crankshaft, a spool valve for switching oil passages, an electromagnetic actuator, and the like. The rotor is accommodated in the housing so as to be relatively rotatable, and at least one vane projects from the outer periphery thereof. The housing has an advance side oil chamber on one side in the circumferential direction of the vane and a retard side oil chamber on the other side in the circumferential direction of the vane. Further, the spool valve moves between the advance angle position, the retard angle position, and the fixed position by being driven by the electromagnetic actuator. CTA and OPA are supplied with hydraulic oil (engine oil) from a common hydraulic oil supply source (oil pump), but CTA is always filled with hydraulic oil (even when the engine is started, etc.). In addition, a check valve is provided in the hydraulic oil supply path to the CTA in order to prevent hydraulic pressure fluctuation in the CTA from affecting (disturbing) the operation of the OPA. In an engine having both intake and exhaust camshafts with a VTC, the check valve causes the hydraulic fluctuation of the CTA in one VTC to be transferred to the other VTC (or other hydraulic control device sharing the hydraulic oil supply path). It is also necessary to prevent disturbance.
JP 2005-147153 A JP 2007-127046 A

  In the conventional CTA described above, various problems as described below have occurred by providing a check valve in the hydraulic oil supply path. For example, since the number of parts and the number of assembly steps increase, the manufacturing cost of CTA increases, and there is a problem that the CTA package becomes large when a check valve is arranged in the rotor. In addition to the case where the spring constituting the check valve is broken, the smoothness of the CTA can also be achieved when the check valve is stuck in the open or closed state due to contaminants (dust or sludge) in the hydraulic oil. There was also a possibility that operation might be inhibited.

  The present invention has been made in view of the above situation, and an object thereof is to provide a variable cam phase internal combustion engine that realizes reduction in manufacturing cost, suppression of malfunction, and the like.

  A first invention is a cam phase variable internal combustion engine in which a cam phase is variably controlled within a predetermined angle range, and a first rotating member that rotates in synchronization with a crankshaft and a camshaft rotate together. A second rotating member coupled to the first rotating member so as to be relatively rotatable, an advance side oil chamber and a retard side oil chamber filled with hydraulic oil, the first rotating member and the second rotating member; The cam torque acting on the camshaft is used as a driving force, and the first rotating member and the first are changed according to the change of the communication form between the advance side oil chamber and the retard side oil chamber. A cam torque actuator for changing or maintaining an angular phase with the two-rotating member, a communication mode switching means for switching a communication mode between the advance side oil chamber and the retard side oil chamber, and hydraulic oil from a hydraulic oil supply source Via the communication mode switching means Wherein a cam phase variable type internal combustion engine having a hydraulic fluid supply passage for supplying the cam torque actuator, characterized in that the orifice in the hydraulic fluid supply path is interposed Te.

  According to a second aspect of the present invention, in the variable cam phase internal combustion engine according to the first aspect of the present invention, an advance side oil chamber and a retard side oil chamber are provided between the first rotating member and the second rotating member. A hydraulic actuator that changes an angular phase between the first rotating member and the second rotating member by supplying hydraulic oil to at least one of the advance side oil chamber and the retard side oil chamber; And a hydraulic control means for controlling hydraulic oil supply to the hydraulic actuator, wherein the hydraulic oil supply path is connected to the cam torque actuator and a first branch supply path is connected to the hydraulic actuator. The orifice is installed in the first branch supply path.

  According to a third invention, in the cam phase variable internal combustion engine according to the first or second invention, the orifice area of the orifice is smaller than a minimum passage area in the cam torque actuator.

  According to a fourth invention, in the cam phase variable internal combustion engine according to the first to third inventions, the communication mode switching means is a spool valve, and the orifice is formed in a spool of the spool valve. Features.

  According to the first invention, since no check valve is required in the hydraulic oil supply path to the CTA, the number of parts and the number of assembling steps are reduced, the manufacturing cost is reduced, and the operation caused by contaminants in the hydraulic oil. Defects are less likely to occur. Further, according to the second invention, since the orifice is located downstream of the branch portion of the second hydraulic oil supply path in the first hydraulic oil supply path, the hydraulic oil can be operated even if a relatively large hydraulic pressure fluctuation occurs in the CTA. The supply of hydraulic oil from the supply source to the OPA is not hindered. Further, according to the third invention, the response performance and holding performance of the cam torque actuator are not easily inhibited by the orifice. Further, according to the fourth invention, the layout and formation of the orifices are facilitated.

Hereinafter, an embodiment of a cam phase variable internal combustion engine according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view of a main part of an automotive engine according to the embodiment, FIG. 2 is an exploded perspective view of the VTC actuator according to the embodiment, and FIG. 3 is a schematic configuration diagram of the VTC actuator according to the embodiment. FIG. 4 is a longitudinal sectional view of the spool valve according to the embodiment.

<< Configuration of Embodiment >>
<Overall configuration>
An engine (cam phase variable internal combustion engine) E shown in FIG. 1 is a DOHC 4-valve four-cycle in-line four-cylinder gasoline engine mounted on an automobile. An intake valve 2 for each cylinder is provided in the cylinder head 1. And an exhaust valve 3, an intake camshaft 4 and an exhaust camshaft 5 that drive the intake and exhaust valves 2 and 3. Both camshafts 4 and 5 are rotationally driven by the crankshaft 10 at a rotational speed of 1/2 through the crank sprocket 6, the cam chain 7, the intake cam sprocket 8, and the exhaust cam sprocket 9. The crankshaft 10 is connected to the piston 12 via a connecting rod 11 and drives an oil pump (operating oil supply source) 14 installed obliquely downward via a chain 13. A VTC actuator 21 is attached to the front end of the intake camshaft 4, and an oil passage 16 for supplying hydraulic oil (engine oil) from the oil pump 14 to the VTC actuator 21 is formed in the cylinder head 1 and the cylinder block 15. ing.

<VTC actuator>
As shown in FIG. 2, the VTC actuator 21 includes a housing (first rotating member) 22 having an intake cam sprocket 8 formed on the outer periphery thereof, is rotatably held in the housing 22, and is then attached to the front end of the intake camshaft 4. A rotor (second rotating member) 23 to which the surface is fastened, a front plate 24 covering the front surface of the housing 22, a back plate 25 covering the rear surface of the housing 22, a reed valve 26 disposed on the inner peripheral side of the front plate 24, a lead By being controlled by a reed valve cover 27 for fixing the valve 26 to the rotor 23, a bias spring 28 for relatively rotating the housing 22 and the rotor 23 in the advance direction, a spool valve 29 installed at the shaft center, and an engine ECU. Linear solenoid 31 for driving the spool valve 29, rotor 3, the lock pin spring 34 that urges the lock pin 33 toward the back plate 25, the rotation limit pin 36 that is held by the rotor 23, and the rotation limit pin 36 urges toward the back plate 25. The limiting pin spring 37 is a constituent element. The spool valve 29 includes a valve sleeve 38 held at the axis of the intake camshaft 4 and the rotor 23, a spool 39 slidably fitted in the valve sleeve 38, and the spool 39 attached to the linear solenoid 31 side. And a return spring 40 that is energized.

  As shown in FIG. 3, a relatively thick first vane 41, a relatively thin second vane 42, and a relatively thick third vane 43 are erected on the outer periphery of the rotor 23, Formed on the inner periphery of the housing 22 are first to third vane chambers 45 to 47 for accommodating these vanes 41 to 43 so as to be relatively rotatable with a predetermined angle. In the present embodiment, the first vane 41 and the first vane chamber 45 are components of the first OPA 61, the second vane 42 and the second vane chamber 46 are components of the second OPA 62, and the third vane 43 and the second vane chamber 46. The 3-vane chamber 47 is a component of the CTA 63.

  The third vane 43 accommodates a lock pin 33 and a lock pin spring 34 (see FIG. 2), and the back plate 25 has a lock hole 25a into which the lock pin 33 is fitted. The first vane 41 accommodates a rotation limiting pin 36 and a limiting pin spring 37 (see FIG. 2), while the back plate 25 has an arcuate rotation limiting groove 25b into which the rotation limiting pin 36 is fitted. It is installed. In the case of the embodiment, the lock pin 33 and the rotation limiting pin 36 are arranged so that the centrifugal force accompanying the rotation of the intake camshaft 4 hardly acts during operation of the engine E so that the shaft center of the VTC actuator 21 (that is, the intake camshaft 4 It is installed parallel to the axis of 3, a member denoted by reference numeral 49 is a rotor-side seal provided on the outer periphery of the rotor 23, and a member denoted by reference numeral 50 is a housing-side seal provided on the inner periphery of the housing 22.

  The first and second vane chambers 45 and 46 are advance chambers (hereinafter, referred to as hydraulic chambers) in which hydraulic oil from the spool valve 29 is supplied by the first and second vanes 41 and 42 via the advance oil passages 51 and 52. 45a, 46a and retard side oil chambers (hereinafter simply referred to as retard chambers) 45b, 46b to which hydraulic oil from the spool valve 29 is supplied via the retard passages 53, 54 It is divided into each. Further, the third vane chamber 47 is connected to the advance valve chamber 47 a that communicates with the spool valve 29 via the retard oil passage 56 and the retard valve that communicates with the spool valve 29 via the advance oil passage 55. It is partitioned into a corner chamber 47b.

<Spool valve>
As shown in FIG. 4, the spool valve 29 is press-fitted into the shaft centers of the intake camshaft 4, the rotor 23 and the front plate 24, and the spool 39 is driven in the axial direction by the rod 31 a of the linear solenoid 31. The oil passage is switched when the spool 39 is returned to the linear solenoid 31 side by the urging force of the return spring 40. During operation of the engine E, the working oil from the camshaft journal 72 is constantly supplied to the spool valve 29 via the working oil supply passage 71 formed in the intake camshaft 4.

  The valve sleeve 38 has a supply port 81 communicating with the hydraulic oil supply passage 71, an OPA side advance port 82 communicating with the advance oil passages 51, 52, and an OPA side retard angle communicating with the retard passages 53, 54. CTA side advance port 84 communicating with port 83, advance oil passage 55, CTA side advance port 85 communicating with retard oil passage 56, and central chamber of CTA 63 (central oil) via central oil passage 57 A CTA side central port 86 communicating with the chamber 47c is formed.

  The spool 39 has a bottomed cylindrical shape with an opening on the return spring 40 side, and an open end is closed by a plug 90 so as to form a hollow portion 91 therein. Further, the spool 39 has four supply holes 92 for introducing the hydraulic oil from the supply port 81 into the hollow portion 91, and the supply port at the advanced position (the state where the spool 39 has moved to the right in FIG. 4). OPA side advance angle groove (advance side supply / discharge means) 93 for communicating 81 and OPA side advance port 82, and hollow portion 91 in the retard position (the state where spool 39 has moved leftward in FIG. 4). The OPA-side retarding port 83 communicates with four OPA-side retarding communication holes (retarding-side supply / discharge means) 94, and the advance oil passage 55 and the central oil passage 57 communicate with each other at the advance position. A CTA side groove (communication mode switching means) 95 for communicating the retard oil passage 56 and the central oil passage 57 at the angular position, and four orifices 96 for communicating the hollow portion 91 and the CTA side groove 95. Yes. In the holding position shown in FIG. 4, only the central oil passage 57 opens into the CTA side groove 95.

  In the case of the present embodiment, the CTA side groove 95 and the oil passages 55 to 57 on the CTA 63 side constitute a first branch supply passage, and the oil passages 51 to 54 on the first and second OPA 61 and 62 side are the second branch. A supply path is configured. Further, the orifice 96 is set so that its total throttle area (the sum of the passage areas of the four orifices 96) is smaller than the minimum passage area in the CTA 63.

<< Operation of Embodiment >>
Hereinafter, the operation of the present embodiment will be described with reference to the schematic diagrams of FIGS.
<When starting the engine>
When the engine E is started, the hydraulic oil (engine oil) discharged from the oil pump 14 flows into the supply port 81 of the spool valve 29 (valve sleeve 38) via the oil passage 16 and the camshaft journal 72. Then, it is introduced into the hollow portion 91 of the spool 39 from the supply hole 92. After the hydraulic oil is filled in the hollow portion 91 of the spool 39, the hydraulic oil flows into the CTA side groove 95 through the orifice 96, and passes through the central oil passage 57 (or the advance oil passage depending on the position of the spool 39). The central chamber 47c, the advance chamber 47a, and the retard chamber 47b are filled (through 55 and the retard oil passage 56).

<Advance operation>
When the intake camshaft 4 is advanced during operation of the engine E, the engine ECU moves the spool 39 of the spool valve 29 to the advance position (rightward in the figure) by the linear solenoid 31 as shown in FIG. The OPA side advance groove 93 and the advance oil passages 51 and 52 are communicated with each other. Then, the hydraulic oil supplied from the oil pump 14 via the oil passage 16 passes through the OPA side advance groove 93 and the advance oil passages 51 and 52, and the advance chambers 45a on the first and second OPA 61 and 62 sides. , 46a and relatively rotate the first and second vanes 41, 42 toward the advance side. The hydraulic oil in the retarding chambers 45b, 46b on the first and second OPA 61, 62 side is discharged to the outside from the left side of the spool 39 via the retarding passages 53, 54.

  On the other hand, in the CTA 63, the advance oil passage 55 and the central oil passage 57 are communicated via the CTA side groove 95 with the movement of the spool 39 to the advance position. The advance cam torque acts on the intake camshaft 4 and the second valve body 26b of the reed valve 26 opens each time the rotor 23 rotates relative to the housing 22 toward the advance side. The hydraulic oil flows into the advance chamber 47a and relatively rotates the third vane 43 toward the advance side. Further, when the retard side cam torque is applied, the first and second valve bodies 26a, 26b of the reed valve 26 are closed, and the cam phase is maintained without moving the hydraulic oil.

  By the operations of the first and second OPAs 61 and 62 and the CTA 63, the rotor 23 rotates relative to the housing 22 in the clockwise direction in the drawing, and the intake camshaft 4 advances. During normal operation of the engine E, the lock pin 33 is moved to the release side by the hydraulic pressure supplied from the CTA 63 (disengaged from the lock hole 25a), and the rotation limit pin 36 is released by the hydraulic pressure supplied from the oil passage 16. (Disengagement from the rotation restricting groove 25b), the housing 22 and the rotor 23 can rotate relative to each other within the maximum rotation range.

<Delayed operation>
When retarding the intake camshaft 4 during operation of the engine E, the engine ECU moves the spool 39 to the retarded position (leftward in the figure) by the linear solenoid 31 as shown in FIG. Then, in the first and second OPAs 61 and 62, the hydraulic oil supplied from the oil pump 14 via the oil passage 16 is supplied to the supply hole 92, the hollow portion 91 of the spool 39, the OPA side retard communication hole 94, and the retard angle. It flows into the retarded angle chambers 45b, 46b on the first and second OPA 61, 62 side through the passages 53, 54, and relatively rotates the first and second vanes 41, 42 to the retarded angle side. The hydraulic oil in the advance chambers 45a, 46a on the first and second OPA 61, 62 side is discharged to the outside from the right side of the spool 39 via the advance oil passages 51, 52.

  On the other hand, in the CTA 63, the retard oil passage 56 and the central oil passage 57 are communicated via the CTA side groove 95 with the movement of the spool 39 to the retard position. Then, the retard cam torque acts on the intake camshaft 4, and the hydraulic oil in the advance chamber 47a flows into the retard chamber 47b with respect to the housing 22 to rotate the third vane 43 relative to the retard side. Further, when the cam torque on the advance side acts, the first and second valve bodies 26a, 26b of the reed valve 26 are closed, and the cam phase is maintained without moving the hydraulic oil.

  By the operation of the first and second OPAs 61 and 62 and the CTA 63, the rotor 23 rotates relative to the housing 22 counterclockwise in the figure, and the intake camshaft 4 is retarded.

<Holding operation>
When the target cam phase is obtained by the advance angle operation or the retard angle operation, the engine ECU moves the spool 39 to the holding position (center in the figure) by the linear solenoid 31 as shown in FIG. Then, in the first and second OPAs 61 and 62, the hydraulic oil in the advance chambers 45a and 46a is enclosed by the spool 39, and the first and second vanes 41 and 42 cannot be rotated. On the other hand, even in the CTA 63, the hydraulic oil cannot move between the advance chamber 47a and the retard chamber 47b, and the third vane 43 cannot rotate. By the operations of the first and second OPAs 61 and 62 and the CTA 63, the rotor 23 does not rotate relative to the housing 22, and the cam phase of the intake camshaft 4 is maintained.

<Effect of embodiment>
During the advance angle operation or the retard angle operation described above, frequent hydraulic pressure fluctuations occur in the CTA 63 as the rotor 23 rotates relative to the housing 22. However, in this embodiment, the hydraulic pressure fluctuation is sealed in the first branch supply path (the CTA side groove 95 and the oil paths 55 to 57 on the CTA 63 side) by the orifice 96, and the second branch supply path (advanced oil path). 51, 52 and retarding passages 53, 54) are prevented from being disturbed by the first and second OPAs 61, 62 communicating with each other. In addition, since the orifice 96 is a simple through-hole and is formed in a plurality, it is difficult for malfunction and blockage due to contaminants to occur, and smooth operation of the CTA over a long period of time is realized. Furthermore, in this embodiment, since the total throttle area of the orifice 96 is smaller than the minimum passage area in the CTA 63, high response performance and holding performance of the CTA 63 are realized.

  As described above, in the present embodiment, by forming the orifice 96 in the spool 39 of the spool valve 29, the number of component parts and assembly man-hours of the VTC actuator 21 are reduced, and the reliability of the CTA 63 is improved. I was able to.

  Although the description of the specific embodiment is finished as above, the present invention is not limited to the above embodiment and can be widely modified. For example, although the above embodiment is an application of the present invention to an in-line four-cylinder DOHC gasoline engine, it is naturally applicable to a V-type engine, a diesel engine, or the like. In the above embodiment, the present invention is applied to an engine having a VTC only on the intake camshaft side. However, the present invention may be applied to an engine having a VTC also on the exhaust camshaft side, and supplying hydraulic oil. You may apply to the engine provided with the other hydraulic equipment which shares a path. Further, in the above embodiment, the present invention is applied to a VTC actuator having CTA and OPA as cam phase control means. However, the present invention is also applicable to a VTC actuator having only CTA. Further, the part where the orifice is formed is not limited to the spool of the spool valve, and it is desirable to appropriately set it according to the form of the hydraulic circuit. In addition, the specific configurations of the engine and the valve mechanism including the VTC actuator can be changed as appropriate without departing from the gist of the present invention.

It is a principal part perspective view of the engine which concerns on embodiment. It is a disassembled perspective view of the VTC actuator which concerns on embodiment. It is a schematic block diagram of the VTC actuator which concerns on embodiment. It is a longitudinal cross-sectional view of the spool valve which concerns on embodiment. It is a mimetic diagram showing advance angle operation of the VTC actuator concerning an embodiment. It is a schematic diagram which shows the retardation operation | movement of the VTC actuator which concerns on embodiment. It is a schematic diagram which shows holding | maintenance operation | movement of the VTC actuator which concerns on embodiment.

Explanation of symbols

4 intake camshaft 16 oil passage 21 VTC actuator 22 housing 23 rotor 29 spool valve 38 valve sleeve 39 spool 45a, 46a advance angle chamber (advance angle side oil chamber)
45b, 46b Retarded chamber (retarded side oil chamber)
47a Advance angle chamber (advance angle side oil chamber)
47b Retarded chamber (retarded oil chamber)
47c Central chamber 51, 52 Advance oil passage (second branch supply passage)
53, 54 Retarded passage (second branch supply passage)
55 Advance oil passage (first branch supply passage)
56 Retardation oil passage (first branch supply passage)
57 Central oil passage (first branch supply passage)
61 1st OPA (hydraulic actuator)
62 2nd OPA (Hydraulic Actuator)
63 CTA (cam torque actuator)
93 OPA side advance groove (advance side supply / discharge means)
94 OPA side retard communication hole (retard side supply / discharge means)
95 CTA side groove (contact type switching means)
96 Orifice E Engine (Cam phase variable internal combustion engine)

Claims (4)

A cam phase variable internal combustion engine in which the cam phase is variably controlled within a predetermined angle range,
A first rotating member that rotates in synchronization with the crankshaft;
A second rotating member that rotates integrally with the camshaft and is connected to the first rotating member so as to be relatively rotatable;
An advance angle side oil chamber and a retard angle side oil chamber filled with hydraulic oil are provided between the first rotating member and the second rotating member, and a cam torque acting on the cam shaft is used as a driving force. A cam torque actuator that changes or maintains an angular phase between the first rotating member and the second rotating member in accordance with a change in communication form between the advance side oil chamber and the retard side oil chamber;
A communication mode switching means for switching a communication mode between the advance side oil chamber and the retard side oil chamber;
A variable cam phase internal combustion engine comprising a hydraulic oil supply path for supplying hydraulic oil from a hydraulic oil supply source to the cam torque actuator via the communication mode switching means;
A cam phase variable internal combustion engine, wherein an orifice is interposed in the hydraulic oil supply path. An advance side oil chamber and a retard side oil chamber are provided between the first rotation member and the second rotation member, and hydraulic oil is provided in at least one of the advance side oil chamber and the retard side oil chamber. Is supplied, a hydraulic actuator that changes an angle phase between the first rotating member and the second rotating member;
Hydraulic control means used for hydraulic oil supply control to the hydraulic actuator,
The hydraulic oil supply path has a first branch supply path connected to the cam torque actuator, and a second branch supply path connected to the hydraulic actuator,
The cam phase variable internal combustion engine according to claim 1, wherein the orifice is installed in the first branch supply path.   3. The variable cam phase internal combustion engine according to claim 1, wherein a throttle area of the orifice is smaller than a minimum passage area in the cam torque actuator.   The cam phase variable internal combustion engine according to any one of claims 1 to 3, wherein the communication mode switching means is a spool valve, and the orifice is formed in a spool of the spool valve. organ.

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