JP3551071B2 - Solenoid driven valve - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electromagnetically driven valve, and more particularly to an electromagnetically driven valve having a zero lash adjuster interposed between a valve body and an armature.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, an electromagnetically driven valve disclosed in Japanese Patent Application Laid-Open No. 10-252426 is known. The electromagnetically driven valve has a valve body that functions as an intake valve or an exhaust valve of an internal combustion engine, an armature that works in conjunction with the valve body, and a valve opening that applies an electromagnetic force to the armature in the valve opening direction and the valve closing direction. And a valve closing electromagnet. Therefore, according to the above-mentioned conventional electromagnetically driven valve, the valve element can be opened and closed by exciting each electromagnet alternately.
[0003]
Further, the conventional electromagnetically driven valve is configured such that a gap is formed between the armature and the valve body in a state where the armature is attracted to the valve closing electromagnet and the valve body is seated on the valve seat. ing. According to this configuration, even when the relative displacement between the valve body and the armature occurs due to the thermal expansion of the valve body and the wear of the seating surface between the valve body and the valve seat, the relative displacement is absorbed by the gap. Thus, the valve can be reliably displaced until the valve is seated on the valve seat. However, when a gap is formed between the valve body and the armature, the armature collides with the valve body when the valve body is opened, so that a collision noise is generated, and the operation noise of the electromagnetically driven valve increases. I will.
[0004]
In order to prevent such an increase in the operating noise, a zero lash adjuster may be provided between the valve body and the armature. The zero lash adjuster is a mechanism that expands and contracts according to the relative displacement between the valve body and the armature. By providing the zero lash adjuster, it is possible to reduce the operating noise by absorbing a relative displacement between the valve element and the armature, while preventing a gap from being generated between the valve element and the armature.
[0005]
[Problems to be solved by the invention]
However, in a zero lash adjuster configured to extend when a driving force (for example, hydraulic pressure) is applied from the outside, a power source (for example, a hydraulic pump) is required in order for the zero lash adjuster to function. Extra energy is required to operate such a power source.
[0006]
The present invention has been made in view of the above points, and an object of the present invention is to reduce a driving force to be applied to a zero lash adjuster while maintaining the operation noise within an allowable range in an electromagnetically driven valve having a zero lash adjuster. And
[0007]
[Means for Solving the Problems]
The above object is as described in claim 1.
A valve element that functions as an intake valve or an exhaust valve of an internal combustion engine, an armature that drives the valve element, and the valve element is interposed between the valve element and the armature, and a driving force is applied to the valve element, A zero lash adjuster that extends following the change in the interval with the armature,
Engine operation sound detection and estimation means for detecting or estimating the operation sound of the internal combustion engine,
SaidThe higher the operating sound by the engine operating sound detection and estimation means, the moreThe driving force applied to the zero lash adjusterReduceAnd a driving force changing means.
[0008]
In the first aspect of the invention, if the driving force applied to the zero lash adjuster is insufficient, the amount of extension of the zero lash adjuster decreases, and a gap is generated between the valve body and the armature. When such a gap occurs, the operating noise of the electromagnetically driven valve increases due to a collision noise between the valve body and the armature. By the way, when the operating noise of the internal combustion engine is loud, even if the electromagnetically driven valve emits a loud operating noise, the operating noise is hardly noticeable. That is, when the operating noise of the internal combustion engine is large, the allowable range of the operating noise of the electromagnetically driven valve becomes large. Therefore, according to the present invention, it is possible to reduce the driving force applied to the zero lash adjuster while keeping the operation sound of the electromagnetically driven valve within an allowable range. In the present invention, the operation sound of the internal combustion engine is an operation sound other than a sound associated with the opening and closing operation of the intake valve and the exhaust valve, that is, combustion noise in the combustion chamber, movement of the piston, rotation of the crankshaft, and the like. Means driving noise.
[0009]
Further, the above object is as described in claim 2.
A valve element that functions as an intake valve or an exhaust valve of the internal combustion engine, an armature that drives the valve element, and the valve element is interposed between the valve element and the armature and provided with a driving force, A zero-lash adjuster that extends following the change in the interval with the armature,
Engine operation sound detection and estimation means for detecting or estimating the operation sound of the internal combustion engine,
A driving force for reducing the driving force applied to the zero lash adjuster when the driving sound by the engine operation sound detection estimating means is higher than a predetermined value, compared to when the driving sound is lower than the predetermined value. And a change means.
In the invention described in claim 2, the driving force applied to the zero lash adjuster is reduced when the driving sound is higher than a predetermined value, as compared with when the driving sound is lower than the predetermined value. Therefore, according to the present invention, it is possible to reduce the driving force applied to the zero lash adjuster while keeping the operation sound of the electromagnetically driven valve within an allowable range.
In this case, the operating noise of the internal combustion engine increases as the load on the internal combustion engine increases and as the rotational speed increases. Therefore, the claims3As described in the above, the engine operation sound detection and estimation means can estimate the operation sound based on at least one of a load and a rotation speed of the internal combustion engine..
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows the configuration of an electromagnetically driven valve 10 according to one embodiment of the present invention. FIG. 2 shows a configuration of an internal combustion engine to which the electromagnetically driven valve 10 is applied. The electromagnetically driven valve 10 of this embodiment is provided corresponding to each exhaust valve and each intake valve of the internal combustion engine. First, the configuration of the internal combustion engine will be briefly described with reference to FIG.
[0013]
As shown in FIG. 2, the internal combustion engine is controlled by an electronic control unit (hereinafter, referred to as ECU) 11. The internal combustion engine includes a cylinder block 200. Inside the cylinder block 200, a cylinder 202 and a water jacket 204 are formed. The water jacket 204 is provided with a water temperature sensor 206. Water temperature sensor 206 outputs a signal corresponding to the temperature of the cooling water in water jacket 204 (hereinafter, referred to as water temperature THW) to ECU 11. The ECU 11 detects the water temperature THW based on the output signal of the water temperature sensor 206.
[0014]
A piston 208 is slidably housed in the cylinder 202. A combustion chamber 210 is defined above the piston 208 inside the cylinder 202. The tip of the ignition plug 212 is exposed in the combustion chamber 210. In the combustion chamber 210, an intake port 214 and an exhaust port 216 are also opened.
An intake valve 218 and an exhaust valve 220 are provided at openings of the intake port 214 and the exhaust port 216 to the combustion chamber 210, respectively. The intake valve 218 and the exhaust valve 220 are opened and closed by the electromagnetically driven valve 10, respectively.
[0015]
An intake manifold 222 communicates with the intake port 214. A fuel injection valve 224 is provided in the intake manifold 222. The intake manifold 222 communicates with an intake pipe 228 via a surge tank 226. A throttle valve 230 is provided in the intake pipe 228. An amount of air corresponding to the opening of the throttle valve 230 is sucked into the intake pipe 228 via the air cleaner 232. An air flow meter 234 is provided upstream of the throttle valve 230 in the intake pipe 228. The air flow meter 234 outputs a signal corresponding to the amount of air sucked into the intake pipe 228 (hereinafter, referred to as an intake air amount GA) to the ECU 11. The ECU 11 detects the intake air amount GA based on the output signal of the air flow meter 234.
[0016]
On the other hand, an exhaust passage 236 communicates with the exhaust port 216. An exhaust gas temperature sensor 238 is provided in the exhaust passage 236. The exhaust sound sensor 238 outputs a signal corresponding to the temperature of the exhaust gas discharged from the combustion chamber 210 (hereinafter, referred to as an exhaust temperature Te) to the ECU 11. The ECU 11 detects the exhaust gas temperature Te based on the output signal of the exhaust gas temperature sensor 238.
[0017]
The internal combustion engine is provided with a rotation speed sensor 240. The rotation speed sensor 240 outputs a signal corresponding to the rotation speed of the internal combustion engine to the ECU 11. The ECU 11 detects the rotation speed of the internal combustion engine (hereinafter, referred to as engine rotation speed Ne) based on the output signal of the rotation speed sensor 240.
Next, the configuration of the electromagnetically driven valve 10 will be described in detail with reference to FIG. As shown in FIG. 1, the electromagnetically driven valve 10 includes a valve body 12 that functions as an intake valve 218 or an exhaust valve 220. The valve element 12 is disposed on the lower head 16 so as to be exposed inside the combustion chamber 210 of the internal combustion engine. The intake port 214 and the exhaust port 216 are formed in the lower head 16. A valve seat 20 for the valve element 12 is formed at an opening of the intake port 214 or the exhaust port 216 to the combustion chamber 210. The intake port 214 and the exhaust port 216 enter a conductive state when the valve body 12 is separated from the valve seat 20, and are shut off when the valve body 12 is seated on the valve seat 20.
[0018]
A cylinder head spacer 24 is disposed above the lower head 16 via a heat insulating plate 22. The heat insulating plate 22 is a sheet-shaped member made of a heat insulating material such as bakelite, and has a function of suppressing transmission of high heat generated in the combustion chamber 210 from the lower head 16 to the cylinder head spacer 24. I have. Above the cylinder head spacer 24, an upper head 25 is fixed.
[0019]
The valve body 12 has a valve shaft 26 extending upward. The valve shaft 26 is held by a valve guide 28 so as to be slidable in the axial direction. The valve guide 28 is held by the lower head 16. A spring holding space 30 formed in a cylindrical shape is provided in a portion of the lower head 16 surrounding a substantially upper half of the valve shaft 26. The upper end of the valve guide 28 is exposed inside the spring holding space 30. A valve stem seal 31 is mounted around the upper end of the valve guide 28 in the spring holding space 30.
[0020]
A cotter 32 is mounted near the upper end of the valve shaft 26. The cotter 32 is a substantially cylindrical member having a wedge-shaped outer peripheral surface having a larger diameter as it goes upward in FIG. 1 and having an inward projection on the inner peripheral surface. The protrusion on the inner peripheral surface of the cotter 32 is fitted into a concave portion provided on the outer peripheral surface of the valve shaft 26. A lower retainer 34 is fitted around the outer periphery of the cotter 32.
[0021]
A spring seat 36 is provided on the bottom surface of the spring holding space 30. Between the spring seat 36 and the lower retainer 34, a lower spring 38 that generates an urging force in a direction for separating the lower and the lower retainer 34 is provided. The lower spring 38 urges the valve body 12 upward through the lower retainer 34, that is, in a direction toward the valve seat 20. Hereinafter, the direction in which the valve element 12 moves toward the valve seat 20 is referred to as a valve closing direction, and the direction in which the valve element 12 moves away from the valve seat 20 is referred to as a valve opening direction.
[0022]
Above the valve shaft 26, an armature shaft 42 is disposed coaxially with the valve shaft 26 with a zero lash adjuster 40 therebetween. The configuration of the zero lash adjuster 40 will be described later in detail. At the upper end of the armature shaft 42, a cotter 44 having a vertically symmetric configuration with the cotter 31 is mounted. An applicator 46 is fitted around the cotter 44. The lower end of an upper spring 48 is in contact with the upper surface of the upper retainer 46. A cylindrical upper case 50 is disposed around the upper spring 48. An adjuster bolt 52 is screwed onto the upper part of the upper case 50. The upper end of the upper spring 48 is in contact with the adjuster bolt 52 via a spring guide 54. The upper spring 48 urges the armature shaft 42 downward through the upper retainer 46.
[0023]
An armature 56 is joined to the outer periphery of the armature shaft 42 at the center in the axial direction. The armature 56 is a disk-shaped member made of a soft magnetic material. Above the armature 56, an upper coil 58 and an upper core 60 are provided. Further, a lower coil 62 and a lower core 64 are provided below the armature 56. The upper coil 58 and the lower coil 62 are accommodated in annular grooves 60a and 64a formed in the upper core 60 and the lower core 64, respectively.
[0024]
The upper coil 58 and the lower coil 62 are electrically connected to a drive circuit 65. The drive circuit 65 supplies a command signal corresponding to a control signal provided from the ECU 11 to the upper coil 58 and the lower coil 62, respectively.
The upper core 60 and the lower core 64 have through holes 60b and 64b, respectively, penetrating through the central portions thereof. An upper bush 66 is provided at the upper end of the through hole 60b of the upper core 60. A lower bush 68 is provided at a lower end of the through hole 64b of the lower core 64. The armature shaft 42 is axially slidably held by an upper bush 66 and a lower bush 68. Further, flange portions 60c and 64c are provided at the upper end of the upper core 60 and the lower end of the lower core 64, respectively.
[0025]
In the cylinder head spacer 24, a cylindrical lash adjuster holding space 24a penetrating the upper and lower sides thereof is formed coaxially with the spring holding space 30. The zero lash adjuster 40 described above is held inside the lash adjuster holding space 24a. An upwardly protruding protruding portion 24b is provided near the opening of the lash adjuster holding space 24a on the upper surface of the cylinder head spacer 24, and a cylindrical portion 24c is formed on the top of the protruding portion 24b.
[0026]
A cylindrical core holding space 25a penetrating the upper head 25 is formed coaxially with the spring holding space 30 and the lash adjuster holding space 24a. The upper core 60 is inserted into the core holding space 25a such that the flange portion 60c contacts the upper head 25 via the shim 70, and the lower core 64 contacts the flange portion 64c with the upper head 25. The flange portion 60c of the upper core 60 is sandwiched between the upper head 25 and the flange portion 50a formed at the lower end of the upper case 50. Further, the flange portion 64 c of the lower core 64 is sandwiched between the upper head 25 and the lower bracket 72. By fixing the upper case 50 and the lower bracket 72 to the upper head 25 with fixing bolts 74 and 76, the upper core 60 and the lower core 64 are fixed at a predetermined interval. In the state where the upper core 60 and the lower core 64 are fixed as described above, a predetermined gap is formed between the raised portion 24b of the cylinder head spacer 24 and the lower surface of the lower core 64. The adjuster bolt 52 is adjusted so that the neutral position of the armature 56 is located at the midpoint between the upper core 60 and the lower core 64.
[0027]
The cylinder head spacer 24 is provided with oil supply paths 80 and 82 that communicate with each other. The oil supply passage 82 opens at a predetermined position on the inner wall surface of the lash adjuster holding space 24a. A hydraulic pump 86 is connected to the oil supply path 80 via a hydraulic pipe 87. In this embodiment, the hydraulic pump 88 is configured as an electric pump. A regulator 88 is provided in the hydraulic pipe 87. The regulator 88 adjusts the pressure of the oil pumped from the oil tank 92 by the hydraulic pump 86 to a hydraulic pressure according to a control signal supplied from the ECU 11 and supplies the oil to the oil supply paths 80 and 82. Hereinafter, the oil pressure supplied to the oil supply passages 80 and 82 is referred to as a supply oil pressure Pc.
[0028]
The cylinder head spacer 24 is further provided with an oil recovery hole 90. The oil recovery hole 90 vertically penetrates the cylinder head spacer 24 such that the upper end is opened near the raised portion 24b of the cylinder head 24 and the lower end is opened into the spring holding space 30. The oil recovery hole 90 has a role of collecting the oil leaking upward from the zero lash adjuster 40 and flowing the oil into the spring holding space 30 to provide the oil as lubricating oil for the armature shaft 42 and the valve shaft 26. Since the upper portion of the oil recovery hole 90 is formed by the processing holes 90a and 90b, a large opening area of the oil recovery hole 90 on the upper surface of the cylinder head spacer 24 is ensured.
[0029]
Next, the operation of the electromagnetically driven valve 10 will be described. When the exciting current is supplied to the upper coil 58, an electromagnetic force in the direction toward the upper core 60 acts on the armature 56 by the magnetic flux generated by the upper coil 58. Therefore, as shown in FIG. 1, the armature 56 is displaced until it comes into contact with the upper core 60 against the urging force of the upper spring 48. Hereinafter, the position where the armature 56 contacts the upper core 60 is referred to as the fully closed position of the armature 56, the armature shaft 42, or the valve body 12. In this state, the valve body 12 is seated on the valve seat 20, and the valve body 12 is closed.
[0030]
When the supply of current to the upper coil 58 is stopped in the state where the valve body 12 is closed, the electromagnetic force required to hold the armature 56 at the fully closed position disappears. Therefore, when the supply of the current to the upper coil 58 is stopped, the armature shaft 42 and the valve body 12 are urged by the upper spring 48 to start a single-vibration movement downward. For this reason, the valve element 12 is opened when the valve element 12 separates from the valve seat 20. When the exciting current is supplied to the lower coil 62 when the displacement amount of the armature shaft 42 reaches a predetermined value, an electromagnetic force for urging the armature 56 toward the lower core 64 is generated.
[0031]
When the electromagnetic force acts on the armature 56, the kinetic energy lost by friction is compensated, and the armature 56 is displaced until it comes into contact with the lower core 64 against the urging force generated by the lower spring 38. Hereinafter, the position where the armature 56 contacts the lower core 64 is referred to as the armature 56, the armature shaft 42, or the fully opened position of the valve body 12.
[0032]
In this state, when the supply of the exciting current to the lower coil 62 is stopped, the electromagnetic force required to hold the armature 56 at the fully open position disappears. For this reason, the valve element 12 and the armature shaft 42 start a single-vibration movement upward by the urging force generated by the lower spring 38. When the exciting current is supplied to the upper coil 58 at the time when these displacement amounts reach a predetermined value, the kinetic energy lost due to friction is compensated by the electromagnetic force generated by the upper coil 58, and the armature 56 contacts the upper core 60. Displace to In a state where the armature 56 is in contact with the upper core 60, the valve body 12 is seated on the valve seat 20, and the valve body 12 is again closed.
[0033]
As described above, according to the present embodiment, the current is alternately supplied to the upper coil 58 and the lower coil 62 at an appropriate timing, so that the masses of the movable parts such as the valve body 12 and the armature 56, the lower spring 38 and The valve element 12 can be repeatedly reciprocated between the fully closed position and the fully open position in accordance with a single vibration movement having a cycle determined by the spring constant of the upper spring 48.
[0034]
In the present embodiment, the zero lash adjuster 40 is provided between the valve body 12 and the armature shaft 42 due to the difference in thermal expansion between the valve body 12 and the lower head 16 and the wear of the seating surface between the valve body 12 and the valve seat 20. It has the function of preventing the formation of a gap between both members by absorbing the relative displacement. Hereinafter, the configuration and operation of the zero lash adjuster 40 will be described.
[0035]
FIG. 3 is an enlarged cross-sectional view showing the zero lash adjuster 40 and its peripheral portion. FIG. 3 shows a state realized in a situation where the armature 56 and the valve element 12 are in the fully closed position.
As shown in FIG. 3, the zero lash adjuster 40 includes a plunger body 100. The plunger body 100 is slidably disposed in the lash adjuster holding space 24a in the axial direction. The plunger body 100 is a substantially cylindrical member whose one end (the lower end in FIG. 2) is closed. The plunger body 100 includes a spring holding portion 100a provided at a lower end thereof, and a plunger holding portion 100b having a larger diameter than the spring holding portion 100a.
[0036]
A plunger 102 is slidably provided in the plunger holding portion 100b of the plunger body 100 in the axial direction. A hydraulic chamber 104 is defined between the lower bottom surface of the plunger 102 in FIG. 2 and the lower bottom surface of the spring holding portion 100a.
The plunger 102 has, on its outer peripheral surface, a large-diameter portion 102a that slides on the inner peripheral surface of the plunger holding portion 100b, and a small-diameter portion 102b provided at the upper end in FIG. On the other hand, a stopper ring 106 is press-fitted into the upper end of the inner peripheral surface of the plunger accommodating portion 100b. The stopper ring 106 has an inner diameter smaller than the outer diameter of the large diameter portion 102a of the plunger 102. Accordingly, the upward displacement of the plunger 102 inside the plunger holding portion 100b is regulated by the contact between the step between the large diameter portion 102a and the small diameter portion 102b and the stopper ring 106. The plunger 102 also includes a reservoir chamber 108 that opens upward, and a communication passage 110 that communicates the reservoir chamber 108 with the hydraulic chamber 104.
[0037]
In the hydraulic chamber 104, a retainer 112 and a plunger spring 114 are provided. The plunger spring 114 urges the plunger 102 upward via the retainer 112. A check ball 116 and a check ball spring 118 are provided inside the retainer 112. The check ball spring 118 urges the check ball 116 toward the opening of the communication passage 110. The check ball 116 and the check ball spring 118 function as a check valve that opens only when the pressure in the hydraulic chamber 104 becomes lower than that in the reservoir chamber 108.
[0038]
The zero lash adjuster 40 also includes a reservoir cap 120. The reservoir cap 120 is a cylindrical member having one end (the lower end in FIG. 3) closed. The reservoir cap 120 is slidably disposed in the lash adjuster holding space 24a such that the bottom surface thereof is in contact with the upper end surface of the plunger 102. On the lower bottom surface of the reservoir cap 120, an overflow recess 122, which is partially cut away, is provided. The overflow recess 122 is always in communication with the reservoir chamber 108.
[0039]
The lower end surface of the armature shaft 42 is in contact with the inner bottom surface of the reservoir cap 120. On the other hand, the upper end surface of the valve shaft 26 is in contact with the outer bottom surface of the plunger body 100. Further, the oil supply passage 82 has an inner peripheral surface of the lash adjuster holding space 24a so as to communicate with the overflow recess 122 in a state shown in FIG. 3 (that is, a state in which the armature 56 and the valve body 12 are in the fully closed position). It is open to.
[0040]
When the power supply to the upper coil 58 is interrupted in the state shown in FIG. 3, the urging force in the valve opening direction acts on the armature shaft 42 as described above. The force in the valve opening direction is transmitted from the reservoir cap 120 to the plunger 102. When the force transmitted to the plunger 102 exceeds the urging force of the plunger spring 114, the plunger 102 is pressed downward, so that the oil in the hydraulic chamber 104 is pressurized. Therefore, the hydraulic pressure in the hydraulic chamber 104 becomes higher than the hydraulic pressure in the reservoir chamber 108, and the communication passage 110 is closed by the check ball 116. When the communication passage 110 is closed, oil transfer between the hydraulic chamber 104 and the reservoir chamber 108 is prohibited. Therefore, the driving force transmitted to the plunger 102 is transmitted to the plunger body 100 via the hydraulic chamber 104, and the zero lash adjuster 40 is displaced in the valve opening direction together with the armature shaft 42 and the valve body 12. During the process in which the zero lash adjuster 40 is displaced in the valve opening direction, the oil in the hydraulic chamber 104 is pressurized, so that the oil gradually leaks from the hydraulic chamber 104 via the sliding surface between the plunger 102 and the plunger body 100. However, the lash adjuster 40 contracts by a small amount corresponding to the amount of oil leakage.
[0041]
When the armature 56 is displaced until it comes into contact with the lower core 64 and the power supply to the lower coil 62 is stopped, the armature 56 starts to be displaced in the valve closing direction. When the valve element 12 is seated on the valve seat 20, the urging force of the lower spring 38 does not act on the plunger body 100. On the other hand, even after the valve body 12 is seated on the valve seat 20, the armature 56 is further displaced in the valve closing direction by a minute amount corresponding to the contraction of the lash adjuster 40 in the process of displacing the valve body 12 in the valve opening direction. I do. In this case, the plunger 102 attempts to slide upward with respect to the plunger body 100 following the reservoir cap 120 by the urging force of the plunger spring 114, and the hydraulic pressure in the hydraulic chamber 104 decreases. Then, when the pressure of the hydraulic chamber 104 becomes lower than that of the reservoir chamber 108, the check ball 116 is separated from the opening of the communication passage 110, so that the hydraulic chamber 104 and the reservoir chamber 108 communicate with each other. As described above, when the valve element 12 is seated on the valve seat 20, the oil supply path 82 and the overflow recess 122 communicate with each other. For this reason, when the hydraulic chamber 104 and the reservoir chamber 108 communicate with each other, the oil of the supply hydraulic pressure Pe supplied from the hydraulic pump 86 to the oil supply path 80 is supplied from the oil supply path 82 to the hydraulic chamber 104 via the reservoir chamber 108. As a result, the plunger 102 slides upward while maintaining a state in which it is in contact with the reservoir cap 120.
[0042]
In this way, when the valve element 12 reaches the fully closed position, the zero lash adjuster 40 is extended by the supply of the oil pressure Pe to the zero lash adjuster 40, and the valve element 12 and the armature shaft 42 A gap is prevented from occurring between them.
In addition, the change in the interval between the valve shaft 26 and the armature shaft 42 caused by the difference in thermal expansion between the valve body 12 and the lower head 16 and the wear of the seating surface between the valve body 12 and the valve seat 20 are gradually reduced in time. The amount of change in the interval that occurs during one reciprocation of the valve body 12 between the fully closed position and the fully open position is extremely small. For this reason, such a change in the interval is absorbed in a process in which the zero lash adjuster 40 slightly contracted while the valve body 12 is opened extends when the valve body 12 is closed.
[0043]
As described above, the zero lash adjuster 40 slides the plunger body 100 with respect to the plunger 102 when the supply oil Pe is supplied from the oil supply passage 82 when the valve body 12 reaches the vicinity of the fully closed position. When the armature 56 and the valve body 12 reach the fully-closed position, the mechanism prevents a gap from being generated between the valve body 12 and the armature shaft 42. Note that a gap created between the valve body 12 and the armature shaft 42 when the armature 56 and the valve body 12 reach the fully closed position is hereinafter referred to as tappet clearance.
[0044]
Therefore, if the supply oil pressure Pe is insufficient, the zero lash adjuster 40 may not extend sufficiently, and the above-described tappet clearance may occur. When the tappet clearance is generated, the operation sound of the electromagnetically driven valve 10 increases due to the armature shaft 42 colliding with the valve body 12 when the valve body 12 is opened. In the state where the tappet clearance is generated, when the valve is closed, after the valve body 12 is seated on the valve seat 20, the armature 56 is further displaced by the amount of the tappet clearance before contacting the upper core 60. The energization of the upper coil 58 is controlled such that the speed at which the armature 56 contacts the upper core 60 becomes substantially zero. Therefore, when the tappet clearance occurs, the timing at which the valve element 12 is seated on the valve seat 20 is increased, and the speed at which the valve element 12 is seated (hereinafter, the seating speed of the valve element 12) is increased. Also, the operating noise of the electromagnetically driven valve 10 increases. As described above, when the supply oil pressure Pe is insufficient, the operation noise of the electromagnetically driven valve 10 increases.
[0045]
On the other hand, as the supply hydraulic pressure Pe becomes lower, the load on the hydraulic pump 86 decreases, and the power consumption of the hydraulic pump 88 decreases. Therefore, in order to reduce the power consumption of the hydraulic pump 86, it is desirable to suppress the supply oil pressure Pe to a low pressure.
In the present embodiment, in view of the above points, the supply oil pressure Pe is reduced within a range where an increase in the operation sound of the electromagnetically driven valve 10 is allowable.
[0046]
FIG. 4 shows the relationship between the engine speed Ne and the kinetic energy (hereinafter, referred to as seating energy) when the valve body 12 is seated on the valve seat 20 in the case of the electromagnetically driven valve 10 and the valve body 12. The case of a conventional configuration driven by a cam that rotates in synchronization with the rotation of the crankshaft (hereinafter referred to as cam drive) is shown by a solid line and a broken line, respectively.
As described above, the electromagnetically driven valve 10 drives the valve body 12 in accordance with a single vibration movement having a cycle determined by the weight of the movable parts such as the armature 56 and the valve body 12 and the spring constants of the lower spring 38 and the upper spring 48. Things. For this reason, the seating speed of the valve body 12 is constant irrespective of the engine speed Ne, and the seating energy of the valve body 12 is also constant as shown by the solid line in FIG. When the valve body 12 is seated on the valve seat 20, a seating sound corresponding to the seating energy is generated. Therefore, in the electromagnetically driven valve 10, the seating sound of the valve body 12 is constant regardless of the engine speed Ne.
[0047]
On the other hand, in the cam drive, the seating speed of the valve element 12 increases in proportion to the increase in the engine speed Ne. For this reason, as shown by the broken line in FIG. 4, the seating energy of the valve body 12 is proportional to the square of the engine speed Ne. Therefore, in the case of the cam drive, the seating sound increases as the engine speed Ne increases.
In FIG. 4, in the region where the engine speed Ne is equal to or higher than Nc, the seating energy in the cam drive exceeds the seating energy in the electromagnetically driven valve 10. Therefore, in the region where the engine speed Ne is sufficiently higher than Nc, even if the operation sound of the electromagnetically driven valve 10 increases due to the tappet clearance, the operation sound is suppressed to be equal to or less than that of the case of the cam drive. Becomes possible. In other words, based on the operating noise of the conventional cam drive, the allowable range of the operating noise of the electromagnetically driven valve 10 increases as the engine speed Ne increases. The seating surfaces of the valve element 12 and the valve seat 20 are worn according to the seating energy. Therefore, when the seating energy in the electromagnetically driven valve 10 is equal to or less than that in the case of cam drive, the wear of the seating surface is also suppressed to equal to or less than that in the case of cam drive.
[0048]
In addition, as the engine speed Ne increases, the operating noise of the internal combustion engine (meaning noise generated by a cause other than the electromagnetically driven valve 10, such as combustion in a combustion chamber, sliding of a piston, rotation of a crankshaft, etc.) increases. For this reason, in the high-speed operation region of the internal combustion engine, even if the operating noise of the electromagnetically driven valve 10 increases, the occupant of the vehicle does not easily feel a sense of discomfort. Also in this regard, it can be said that the higher the engine speed Ne, the larger the allowable range of the operation sound of the electromagnetically driven valve 10 becomes.
[0049]
Therefore, by reducing the supply oil pressure Pe in the operation region where the engine speed Ne is high, it is possible to reduce the power consumption of the hydraulic pump 86 while keeping the operation noise within an allowable range. Hereinafter, with reference to FIG. 5, the details of the specific processing executed by the ECU 11 in the present embodiment will be described.
FIG. 5 is a flowchart of a routine executed by the ECU 11 to control the supply oil pressure Pe according to the engine speed Ne. The routine shown in FIG. 5 is an interrupt routine started at predetermined time intervals. When the routine shown in FIG. 5 is started, first, the process of step 300 is executed.
[0050]
In step 300, it is determined whether or not the engine speed Ne is less than a predetermined value N0. As a result, if Ne <N0 holds, the process of step 302 is executed next. On the other hand, if Ne <N0 is not satisfied in step 300, the process of step 304 is executed next.
In step 302, a process of controlling the supply oil pressure Pe to a predetermined value P0 by a control signal applied to the regulator 88 is executed. The predetermined value P0 is experimentally obtained in advance as a value of the supply oil pressure Pe that allows the zero lash adjuster 40 to be quickly extended until the tappet clearance becomes zero when the valve body 12 reaches the fully closed position. When the process of step 302 ends, the current routine ends.
[0051]
In step 304, a process of controlling the supply oil pressure Pe to a predetermined value P1 smaller than the predetermined value P0 is executed by a control signal applied to the regulator 88. When the process of step 304 ends, the current routine ends.
As described above, according to the routine shown in FIG. 5, the supply oil pressure Pe is controlled to the predetermined value P0 in the low rotation region where the engine speed Ne is less than the predetermined value N0. In this case, the operating noise of the electromagnetically driven valve 10 is reduced by extending the zero lash adjuster 40 until the tappet clearance becomes zero. Further, in a high rotation region where the engine speed Ne exceeds the predetermined value N0 and the allowable range of the operation sound of the electromagnetically driven valve 10 becomes large, the supply oil pressure Pe decreases from P0 to P1 so that the power consumption of the hydraulic pump 86 is reduced. Is reduced. As described above, according to the present embodiment, by changing the supply oil pressure Pe based on the engine speed Ne, the power consumption of the hydraulic pump 86 can be reduced while suppressing the operation noise of the electromagnetically driven valve 10 to an allowable range. Is possible.
[0052]
Incidentally, the opening and closing frequency of the intake valve 218 and the exhaust valve 220 increases as the engine speed Ne increases. In this case, the power consumption of the electromagnetically driven valve 10 is increased by increasing the frequency of energizing the upper coil 58 and the lower coil 62 of the electromagnetically driven valve 10. That is, the power consumption of the electromagnetically driven valve 10 increases in the high rotation operation range. On the other hand, in the present embodiment, power saving of the hydraulic pump 86 is achieved in such a high-speed operation region, so that it is possible to prevent the power consumption of the entire internal combustion engine from becoming excessive.
[0053]
In the above embodiment, the supply oil pressure Pe is changed in two stages based on the engine speed Ne. However, the present invention is not limited to this, and the supply oil pressure Pe may be changed in three or more stages or continuously so that the supply oil pressure Pe becomes lower as the engine speed Ne increases. Good.
In the above embodiment, the supply oil pressure Pe is reduced by the regulator 88. However, in a configuration in which the regulator 88 is not provided, the supply oil pressure Pe may be changed by the rotation speed of the hydraulic pump 86. Alternatively, the hydraulic pump 86 may be intermittently driven, and the supply hydraulic pressure Pe may be changed according to the drive time.
[0054]
Further, in the above embodiment, the hydraulic pump 86 is an electric pump, but may be a pump driven by rotation of an output shaft of an internal combustion engine as a power source. Also in this case, the power required to drive the hydraulic pump 86 is reduced by lowering the supply oil pressure Pe in the high rotation region of the internal combustion engine, whereby effects such as improvement in fuel efficiency can be obtained.
[0055]
Further, in the above embodiment, the supply oil pressure Pe is reduced in the high rotation region. However, the present invention is not limited to this. In the rotation region, the hydraulic pump 86 may be stopped. In this case, the power consumption of the hydraulic pump 86 becomes zero in the high rotation region, so that power saving can be more effectively achieved.
[0056]
Incidentally, the operating noise of the internal combustion engine also depends on the magnitude of the load, and the operating noise increases as the load increases. Therefore, the load of the internal combustion engine (for example, the intake air amount GA, the opening of the throttle valve 230, the in-cylinder pressure, etc.) is used instead of the engine speed Ne, and the supply hydraulic pressure Pe is reduced when the load exceeds a predetermined value, or The hydraulic pump 86 may be stopped. Alternatively, a noise sensor for detecting the level of the operation sound of the internal combustion engine may be provided, and the operation sound of the internal combustion engine may be directly detected.
[0057]
Next, a second embodiment of the present invention will be described. In the present embodiment, the supply oil pressure Pe is controlled in consideration of the thermal expansion of the valve element 12 in the system configuration shown in FIGS. In this embodiment, the hydraulic pumps 86 are provided corresponding to the electromagnetically driven valve 10 on the intake valve 218 side and the electromagnetically driven valve 10 on the exhaust valve 220 side, respectively. It is assumed that ON / OFF can be controlled by the ECU 11.
[0058]
During operation of the internal combustion engine, heat generated by the combustion in the combustion chamber 210 is transmitted to the exhaust valve 220, so that relatively large thermal expansion occurs in the valve body 12 functioning as the exhaust valve 220. When the valve element 12 undergoes thermal expansion, the distance between the armature shaft 42 and the valve element 12 when the valve element 12 is seated on the valve seat 20 is reduced. In this case, even if the zero lash adjuster 40 does not extend, the tappet clearance is reduced, and an increase in the operating noise of the electromagnetically driven valve 10 is suppressed.
[0059]
Therefore, in the present embodiment, the temperature of the valve body 12 constituting the exhaust valve 220 is estimated based on the exhaust temperature Te, and when the valve body 12 is at a high temperature, the hydraulic pump 220 corresponding to the exhaust valve 220 is stopped. Let it. Hereinafter, with reference to FIG. 6, the contents of specific processing executed by the ECU 11 in the present embodiment will be described.
FIG. 6 is a flowchart of a routine executed by the ECU 11 in the present embodiment. The routine shown in FIG. 6 is an interrupt routine repeatedly started at predetermined time intervals. When the routine shown in FIG. 8 is started, first, the process of step 350 is executed.
[0060]
In step 350, it is determined whether or not the exhaust gas temperature Te is equal to or higher than a predetermined value T0. As a result, when Te ≧ T0 holds, it is determined that the exhaust valve 220 is in a high temperature state. In this case, after the process of stopping the hydraulic pump 86 on the exhaust valve 220 side is executed in step 352, the current routine is ended. On the other hand, if Te ≧ T0 is not satisfied in step 350, then, in step 354, a process of setting the hydraulic pump 86 on the exhaust valve 220 side to the operating state is executed, and then the current routine is ended.
[0061]
As described above, according to the routine shown in FIG. 6, when the tappet clearance becomes small due to the thermal expansion of the exhaust valve 220, the hydraulic pump 86 on the exhaust valve 220 side is stopped. Therefore, according to the present embodiment, it is possible to reduce the power consumption of the hydraulic pump 86 while suppressing an increase in the operating noise of the electromagnetically driven valve 10.
In the second embodiment, the temperature of the valve body 12 is estimated based on the exhaust gas temperature Te. However, the present invention is not limited to this. For example, the temperature of the valve body 12 may be estimated based on the water temperature THW. Good. Since the temperature of the valve body 12 is considered to increase as the load on the internal combustion engine increases, the temperature of the valve body 12 may be estimated based on the load. Further, a temperature sensor such as a thermocouple may be provided on the valve body 12 to directly detect the temperature of the valve body 12.
[0062]
In the second embodiment, the hydraulic pump 86 is provided on the intake valve 218 side and the exhaust valve 220 side. However, the present invention is not limited to this. When the common hydraulic pump 86 is provided for the intake valve 218 and the exhaust valve 220, the supply of the hydraulic pressure to the zero lash adjuster 40 corresponding to the exhaust valve 220 is shut off. For example, a shutoff valve that can be provided may be provided in the hydraulic pipe 87, and when the exhaust valve 220 has a high temperature, the shutoff valve may shut off the hydraulic pressure supply. That is, when the supply of the hydraulic pressure to the zero lash adjuster on the exhaust valve 220 side is cut off, the discharge flow rate of the hydraulic pump 86 is reduced by half, so that the power consumption of the hydraulic pump 86 is reduced.
[0063]
In the second embodiment, the hydraulic pump 86 is stopped when the temperature of the exhaust valve 220 is high. However, the present invention is not limited to this. The power consumption of the hydraulic pump 86 may be reduced by reducing the supply hydraulic pressure Pe. Is also good.
Note that, as the thermal expansion of the valve body 12 increases, the distance between the armature shaft 42 and the valve body 12 in a state where the valve body 12 is seated on the valve seat 20 becomes narrower. The amount of extension of the adjuster 40 is reduced. Therefore, the higher the temperature of the valve body 12 is, the smaller the supply hydraulic pressure Pe required to reduce the tappet clearance to zero is sufficient. Therefore, instead of stopping the hydraulic pump 86 when the temperature of the exhaust valve 220 is high, the supply oil pressure Pe may be reduced as the temperature of the exhaust valve 220 increases. In this case, the zero-rush adjuster 40 can reliably prevent the tappet clearance from occurring, and can save the power of the hydraulic pump 86.
[0064]
Further, in the above embodiment, the exhaust valve 220 is particularly high in temperature, so that the power of the hydraulic pump 86 is reduced when the exhaust valve 220 is at a high temperature. To rise. Therefore, similarly to the exhaust valve 220, the temperature of the intake valve 218 is estimated or measured based on the exhaust temperature Te, the water temperature THW, or the like, and the on / off or discharge pressure of the hydraulic pump 86 on the intake valve 218 side is determined according to the temperature. May be controlled.
[0065]
Further, in the first and second embodiments, the zero lash adjuster 40 functions with hydraulic pressure as a driving force. However, the present invention is not limited to this. For example, the electromagnetic force acts as a driving force. A zero lash adjuster may be used.
In the first and second embodiments, when the ECU 11 executes the processing of step 300 of the routine shown in FIG. 5, the engine operation sound detection estimation described in the claims is performed by the ECU 11 in the routine shown in FIG. By executing the processing of step 350, the valve body temperature detection estimating means described in the claims executes the processing of steps 302 and 304 of the routine shown in FIG. 5 or the processing of steps 352 and 354 of the routine shown in FIG. Thereby, the driving force changing means described in the claims are realized respectively.
[0066]
【The invention's effect】
Claim 1To 3According to the described invention, by changing the driving force to the zero lash adjuster in accordance with the operation sound of the internal combustion engine, the driving force can be reduced while the operation sound of the electromagnetically driven valve is kept within an allowable range..
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an electromagnetically driven valve according to an embodiment of the present invention.
FIG. 2 is a configuration diagram of an internal combustion engine to which the electromagnetically driven valve of the embodiment is applied.
FIG. 3 is an enlarged cross-sectional view of a zero lash adjuster provided in the electromagnetically driven valve of the embodiment and a peripheral portion thereof.
FIG. 4 is a diagram showing the relationship between the engine speed Ne and the kinetic energy (seating energy) when the valve element is seated on a valve seat in the case of the electromagnetically driven valve of the present embodiment and in the case of conventional cam drive. It is.
FIG. 5 is a flowchart of a routine executed by the ECU to control the supply oil pressure Pe based on the engine speed Ne in the embodiment.
FIG. 6 is a flowchart of a routine executed by the ECU to control the supply oil pressure Pe based on the exhaust gas temperature Te in the second embodiment of the present invention.
[Explanation of symbols]
10 Electromagnetic drive valve
11 Electronic control unit (ECU)
12 valve body
40 Zero Rush Adjuster
42 armature shaft
56 Armature
86 hydraulic pump

Claims (3)

A valve element that functions as an intake valve or an exhaust valve of the internal combustion engine, an armature that drives the valve element, and the valve element is interposed between the valve element and the armature and provided with a driving force, A zero-lash adjuster that extends following the change in the interval with the armature,
Engine operation sound detection and estimation means for detecting or estimating the operation sound of the internal combustion engine,
Electromagnetically driven valve, characterized in that it comprises a be that the driving force variation means reducing the higher operating noise, the driving force applied to the zero lash adjuster according to the engine operating sound detection estimating means. A valve element that functions as an intake valve or an exhaust valve of the internal combustion engine, an armature that drives the valve element, and the valve element is interposed between the valve element and the armature and provided with a driving force, A zero-lash adjuster that extends following the change in the interval with the armature,
Engine operation sound detection and estimation means for detecting or estimating the operation sound of the internal combustion engine,
A driving force for reducing the driving force applied to the zero lash adjuster when the driving sound by the engine operation sound detection estimating means is higher than a predetermined value, compared to when the driving sound is lower than the predetermined value. And a change means . The electromagnetically driven valve according to claim 1 or 2,
An electromagnetically driven valve, wherein the engine operation sound detection and estimation means estimates the operation sound based on at least one of a load and a rotation speed of the internal combustion engine .

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