JP4221091B2 - Variable valve gear - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a variable valve operating apparatus that is used when an intake valve or an exhaust valve of an internal combustion engine is controlled to open and close at a timing according to the operating state of the engine.
[0002]
[Prior art]
Conventionally, various devices have been proposed in which the opening / closing timing and opening time of intake and exhaust valves can be changed in a valve train of an internal combustion engine. As such a device, for example, an inconstant velocity joint is interposed between the cam and the camshaft, and the cam is referred to as the camshaft while rotating the cam relative to the camshaft through the inconstant velocity joint. An apparatus has been proposed in which the valve opening / closing timing and opening time can be adjusted by rotating at different speeds. As such a thing, there exists what was described in Unexamined-Japanese-Patent No. 9-280024.
[0003]
[Problems to be solved by the invention]
By the way, the above-described variable valve operating apparatus requires an actuator for simultaneously adjusting the valve opening / closing timing and opening time of each cylinder. Further, in order to control the valve characteristics on the intake side and the exhaust side, a sensor for detecting the state of at least one of the valve characteristics is necessary. For this reason, the variable valve mechanism described in the above-mentioned Japanese Patent Application Laid-Open No. 9-280024 has a structure in which an actuator integrally provided with this sensor is provided at the end of the camshaft.
[0004]
However, like the variable valve mechanism of this publication, when an actuator with an integrated sensor is attached to the end of the camshaft, the overall length of the engine expands, interfering with peripheral equipment in the engine room, There arises a problem that the degree of freedom becomes narrow. In particular, when this structure is applied to an engine having a large displacement, the above-described problem appears remarkably.
[0005]
The present invention solves such a problem, and provides a variable valve system that can shorten the overall length of an internal combustion engine, suppress interference with peripheral devices, and expand the degree of freedom in design. For the purpose.
[0006]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, a variable valve operating apparatus according to the present invention includes a pair of camshafts that are rotatably provided on an intake side and an exhaust side of an internal combustion engine so that driving force is transmitted from a crankshaft, and the intake air Variable valve operating means for changing the valve characteristics of the intake and exhaust valves respectively provided on the side and exhaust side camshafts, and provided on the coaxial end of either the intake side or exhaust side camshafts Driving means for driving one of the variable valve means on the intake side or the exhaust side, and driving means for driving the other variable valve means on the intake side or the exhaust side via a transmission means; a valve state detecting means provided at the end of the same side as said end portion of said driving means at the intake side or coaxially of the other of the cam shaft of the exhaust side is provided to detect the other valve characteristics state, the Internal combustion engine Operating condition detecting means for detecting operating conditions, is characterized in that and control means for controlling the operation of said drive means based on an output of the valve state detection means and the operating condition detecting means.
The transmission means is composed of a plurality of gears meshing with each other, and is arranged between the drive means and the valve state detection means.
Further, the drive means and the valve state detection means are provided at the respective end portions of the intake side and exhaust side camshafts so as to be relatively rotatable, and are connected to the intake side and exhaust side variable valve means. It is attached to the intake-side and exhaust-side camshafts via a rotating cylinder, and the transmission means is provided to connect the intake-side and exhaust-side rotary cylinders. It is.
Furthermore, the transmission means is arranged on the same side in the camshaft axial direction as the end where the driving means is provided.
[0007]
Therefore, the drive means is provided at the coaxial end of either the intake side or exhaust side camshaft, and the valve state detection means is provided at the coaxial end of the other camshaft. The overall length of the internal combustion engine is shortened without increasing the overall length, interference between the internal combustion engine and peripheral devices is suppressed, and the degree of freedom in design can be expanded.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0009]
FIG. 1 shows a schematic configuration of a variable valve operating apparatus according to an embodiment of the present invention, and FIG. 2 shows variable valve timing characteristics of the variable valve operating apparatus of the present embodiment.
[0010]
Each cylinder of the internal combustion engine is provided with an intake valve and an exhaust valve, and a valve operating mechanism for opening and closing the intake valve and the exhaust valve is provided above the cylinder head. This valve mechanism is configured as a variable valve mechanism that can change the opening / closing timing and opening time of the intake and exhaust valves. In this embodiment described below, the variable valve operating apparatus of the present invention will be described as an internal combustion engine applied to a four-valve in-line four-cylinder engine having two intake valves and two exhaust valves in each cylinder.
[0011]
In the variable valve operating apparatus of the present embodiment, as shown in FIG. 1, an intake side camshaft 11 and an exhaust side camshaft 41 that are parallel to each other are rotatably supported by a cylinder head (not shown). Sprockets 61 are fixed to the end portions of 11 and 41, and pulley belts 62 are wound around the sprockets 61 and the crankshaft. Therefore, the rotational motion from the crankshaft is transmitted to the camshafts 11 and 41 via the pulley belt 62 and the sprocket 61.
[0012]
Four cam lobes 12 are attached to the intake camshaft 11 so as to be relatively rotatable corresponding to each cylinder, and a pair of cams 13 is formed in each cam lobe 12. Between the camshaft 11 and the cam lobe 12, an inconstant velocity joint 14 is provided as variable valve operating means for transmitting the rotational speed of the camshaft 11 to the cam lobe 12 at an inconstant velocity. On the other hand, the cylinder head is provided with a pair of intake valves 15 for opening and closing the intake port corresponding to each cylinder, and a roller rocker arm 16 is provided at the upper end of each intake valve 15. Accordingly, when the rotational speed of the camshaft 11 is transmitted to the cam lobe 12 through the inconstant velocity joint 14 at an inconstant velocity, the cam 13 of the cam lobe 12 moves up and down the intake valve 15 through the roller rocker arm 16 and takes in the intake air. It can be opened and closed by changing the opening and closing timing and opening time of the port.
[0013]
On the other hand, four cam lobes 42 are similarly mounted on the exhaust side camshaft 41 so as to be relatively rotatable corresponding to the respective cylinders, and a pair of cams 43 are formed in each cam lobe 42. Between the camshaft 41 and the cam lobe 42, an inconstant velocity joint 44 that transmits the rotational speed of the camshaft 11 to the cam lobe 42 at an inconstant velocity is provided. On the other hand, the cylinder head is provided with a pair of exhaust valves 45 for opening and closing the exhaust port corresponding to each cylinder, and a roller rocker arm 46 is disposed at the upper end of each exhaust valve 45.
[0014]
Here, the camshafts 11 and 41, the cam lobes 12 and 42, the inconstant velocity joints 14 and 44, and the like will be described in detail. The intake side and the exhaust side have substantially the same configuration. The configuration will be described, and description of the exhaust side configuration will be omitted.
[0015]
A pair of cams 13 is formed on the cam lobe 12 mounted on the intake side camshaft 11 so as to be relatively rotatable, and a flange portion 17 is formed adjacent to one cam 13, and the flange portion 17 is engaged therewith. A hole 18 is formed. On the other hand, an eccentric control gear 20 having an eccentric portion 19 is mounted on the camshaft 11 so as to be relatively rotatable, and an eccentric ring 21 is mounted on the outer periphery of the eccentric portion 19 so as to be relatively rotatable. That is, both are arranged so that the rotation center O ₂ of the eccentric ring 21 is eccentric by a predetermined amount m with respect to the rotation center O ₁ of the camshaft 11. Further, notches 22 and 23 are formed on one end face of the eccentric ring 21 at positions opposed to each other by 180 °.
[0016]
An operating arm 24 is fixed at a position between the cam lobe 12 and the eccentric ring 21 in the camshaft 11, and an engagement hole 25 is formed at the distal end in the radial direction. The proximal end portion of the first slider 26 is fitted into the engagement hole 25 of the operating arm 24, and the distal end portion of the first slider 26 is engaged with one notch portion 22 of the eccentric ring 21. The proximal end portion of the second slider 27 is fitted into the engagement hole 18 formed in the flange portion 17 of the cam lobe 12, and the distal end portion of the second slider 27 is engaged with the other notch portion 23 of the eccentric ring 21. Match.
[0017]
As described above, the eccentric ring 21, the operating arm 24, the sliders 26 and 27, etc. are interposed between the camshaft 11 and the cam lobe 12 as the inconstant velocity joint 14, so that the rotation of the camshaft 11 is prevented. The operation in which the eccentric ring 21 and the cam lobe 12 are advanced or delayed is repeated so that the cam lobe 12 rotates at a non-uniform speed with respect to the cam shaft 11.
[0018]
A rotating cylinder 28 is fitted to the end of the camshaft 11 opposite to the sprocket 61 so as to be relatively rotatable. A transmission gear 29 and a control gear 30 are mounted on the rotating cylinder 28. A position sensor 31 as a valve state detecting means is attached to the end of the rotary cylinder 28. The position sensor 31 is composed of a variable resistor or the like, and detects the rotational phase of the control gear 30. A control shaft 32 adjacent to the camshaft 11 and parallel to the camshaft 11 is rotatably supported by the cylinder head. A connection gear 33 that meshes with the control gear 30 and a connection gear 34 that meshes with each eccentric control gear 20 are attached to the control shaft 32.
[0019]
On the other hand, a rotary cylinder 48 is fitted to the end of the camshaft 41 on the exhaust side so as to be relatively rotatable, and a transmission gear 49 and a control gear 50 are attached to the rotary cylinder 48. An actuator 51 as drive means is attached to the end of the rotating cylinder 48. This actuator 51 is a hydraulic actuator, and controls the control gear 50 to reciprocately rotate by controlling the control valve of a hydraulic supply device (not shown) to adjust the supply state of hydraulic oil. A control shaft 52 adjacent to the cam shaft 41 and parallel to the cam shaft 41 is rotatably supported by the cylinder head. A connecting gear 53 that meshes with the control gear 50 and a coupling gear 54 that meshes with each eccentric control gear 47 are attached to the control shaft 52.
[0020]
A transmission gear mechanism 63 composed of a plurality of gears meshing with each other is interposed as a transmission means between the transmission gear 49 on the exhaust side and the transmission gear 29 on the intake side. Accordingly, when the actuator 51 is driven to rotate the exhaust-side rotary cylinder 48, the control shaft 52 is rotated via the control gear 50 and the connecting gear 53, and the transmission gear 49, the transmission gear mechanism 63, and the transmission gear 29 are rotated. The rotary cylinder 28 can be rotated via the control shaft 30, and the control shaft 32 can be rotated via the control gear 30 and the connecting gear 33. At this time, the position sensor 31 detects the rotational phase of the control gear 30. .
[0021]
Here, the operation of the variable valve operating apparatus of the present embodiment, that is, the rotational phase of the eccentric ring 21 and the cam lobe 12 with respect to the rotational phase of the camshaft 11 (camshaft rotational angle) will be described, and the valve opening / closing timing and opening period will be changed. Will be described in detail. Here, only the intake side will be described.
[0022]
As shown in FIG. 2, when the camshaft angle is 0 ° and the rotation center O ₂ of the eccentric ring 21 is at a low-speed position eccentrically downward with respect to the rotation center O ₁ of the camshaft 11, Two sliders 26 and 27 connecting the operating arm 24 and the eccentric ring 21 are on a straight line passing through the rotation centers O ₁ and O ₂ . First, when the cam shaft 11 rotates clockwise from this position to 90 °, the rotation angle θ _B of the eccentric ring 21 becomes smaller than the rotation angle θ _A of the cam shaft 11 by θ _L, and the cam lobe 12 Since the cam 13 is delayed by φ _{L, the} cam 13 rotates at a lower speed than the rotation of the cam shaft 11.
[0023]
Next, when the cam shaft 11 rotates from 90 ° to 180 °, the rotation angle θ _C of the eccentric ring 21 becomes larger than the rotation angle θ _{A of} the cam shaft 11, and the cam 13 rotates at a higher speed than the rotation of the cam shaft 11. It becomes.
[0024]
Further, when the camshaft 11 rotates from 180 ° to 270 °, the rotation angle θ _D of the eccentric ring 21 becomes larger than the rotation angle θ _A of the cam shaft 11 by θ _F , and the cam 13 of the cam lobe 12 has only φ _F. Due to the advance, the cam 13 rotates at a higher speed than the rotation of the camshaft 11.
[0025]
When the camshaft 11 rotates from 270 ° to 360 ° (= 0 °), the rotation angle θ _E of the eccentric ring 21 becomes smaller than the rotation angle θ _{A of} the camshaft 11, and the camshaft 11 rotates more than the camshaft 11 rotates. 13 is a low speed rotation.
[0026]
With such a configuration, the cam lobe 12 can be rotated at an unequal speed by leading or delaying the cam lobe 12 with respect to the cam shaft 11. That is, as described above, when the camshaft 11 rotates from 0 ° to 90 °, if a delay occurs in the cam 13, the opening timing of the intake valve 15 is delayed, and the camshaft 11 rotates from 180 ° to 270 °. When the cam 13 is advanced, the closing timing of the intake valve 15 is advanced, so that the opening time is shortened.
[0027]
Incidentally, the deviation how the phase of the cam lobe 12 (cam 13) relative to the cam shaft 11 can be changed by changing the position of the rotation center O ₂ of the eccentric ring 21 with respect to the rotation center O ₁ of the camshaft 11. That is, the actuator 51 is driven to rotate the control shaft 52 via the exhaust-side rotating cylinder 48, the control gear 50, and the connecting gear 53, and the transmission gear 49, the transmission gear mechanism 63, the transmission gear 29, and the rotating cylinder 28. When the control shaft 32 is rotated via the control gear 30 and the connection gear 33, the eccentric control gears 20 and 47 are rotated via the connection gears 34 and 54, and the eccentricity is integrated with the eccentric control gears 20 and 47. The part 19 rotates to move the eccentric ring 21, and the position of the rotation center O ₂ of the eccentric ring 21 with respect to the rotation center O ₁ of the camshaft 11 can be changed.
[0028]
Then, as shown in FIG. 2, the camshaft angle is 0 °, and the rotational center O ₂ of the eccentric ring 21 is at a high-speed position eccentrically upward with respect to the rotational center O ₁ of the camshaft 11. When the camshaft 11 is rotated up to 90 °, the cam 13 advances to the cam 13 with respect to the camshaft 11 and φ _F is generated, so that the cam 13 rotates at a higher speed than the rotation of the camshaft 11. Next, when the camshaft 11 rotates from 90 ° to 180 °, the cam 13 rotates at a low speed. Further, when the camshaft 11 rotates from 180 ° to 270 °, a delay φ _L is generated in the cam 13 with respect to the camshaft 11, so that the cam 13 rotates at a lower speed than the rotation of the camshaft 11. When the camshaft 11 rotates from 270 ° to 360 ° (= 0 °), the cam 13 rotates at a high speed.
[0029]
With this configuration, when the camshaft 11 rotates from 0 ° to 90 ° and the cam 13 advances, the opening timing of the intake valve 15 is advanced, and the camshaft 11 rotates from 180 ° to 270 °. When the cam 13 is delayed, the closing timing of the intake valve 15 is delayed, so that the opening time becomes longer.
[0030]
Such a change in the opening / closing timing and opening time of the intake valve 15 is controlled by an electronic control unit (ECU) 71 as a control means. The ECU 71 is a crank angle sensor or throttle as an operating state detection means. The actuator 51 is driven and controlled based on the output of the position sensor or the like (Ne, TPS, etc.) and the rotational phase of the control gear 30 detected by the position sensor 31.
[0031]
In this embodiment, a position sensor 31 for detecting valve characteristics (opening / closing timing and opening time of the intake valve 15) is provided at the end of the intake-side camshaft 11, and the valve is provided at the end of the exhaust-side camshaft 51. An actuator 51 for changing the characteristics (opening / closing timing and opening time of the intake valve 15) is provided. Therefore, the total length of the engine does not increase, and the position sensor 31, the actuator 51, and the like do not interfere with peripheral devices in the engine room, and the degree of design freedom can be increased. In particular, when the structure of the present embodiment is applied to an engine with a large displacement, the above-described effects will be remarkably exhibited.
[0032]
Further, by providing the position sensor 31 on the intake side camshaft 11, the operation of each mechanism of the intake system can be detected and controlled with high accuracy, and high output can be secured.
[0033]
In the above-described embodiment, the position sensor 31 is provided on the intake-side camshaft 11 and the actuator 51 is provided on the exhaust-side camshaft 41. However, contrary to the present embodiment, the intake-side camshaft 11 is provided. Alternatively, the actuator 51 may be provided, and the position sensor 31 may be provided on the camshaft 41 on the exhaust side. In this case, since the operation of each mechanism on the exhaust valve side can be detected with high accuracy, the exhaust gas temperature can be adjusted by accurately controlling the internal EGR remaining in the combustion chamber and controlling the opening timing of the exhaust valve, thereby reducing emissions. There is an effect that it can be planned. In the above-described embodiment, the variable valve operating apparatus of the present invention is applied to a four-valve in-line four-cylinder engine. However, the engine type is not limited to this engine, and may be applied to, for example, a V-type six-cylinder engine. .
[0034]
【The invention's effect】
As described above in detail in the embodiment, according to the variable valve operating apparatus of the present invention, the overall length of the internal combustion engine is shortened without increasing the overall length of the camshaft, and interference between the internal combustion engine and peripheral devices is reduced. The degree of freedom of design can be expanded by suppressing the above.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a variable valve operating apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic diagram showing variable valve timing characteristics of the variable valve apparatus according to the present embodiment.
[Explanation of symbols]
11 intake side camshaft 12 cam lobe 13 cam 14 inconstant velocity joint (variable valve operating means)
15 Intake valve 21 Eccentric ring 24 Actuating arm 26 First slider 27 Second slider 31 Position sensor (valve state detecting means)
41 Exhaust-side camshaft 42 Cam lobe 43 Cam 44 Non-uniform velocity joint (variable valve operating means)
45 Exhaust valve 51 Actuator (drive means)
63 Transmission gear mechanism (transmission means)
71 Electronic control unit, ECU (control means)

Claims (4)

A pair of camshafts rotatably provided on the intake side and the exhaust side of the internal combustion engine and transmitting the driving force from the crankshaft;
Variable valve operating means provided on the intake side and exhaust side camshafts, respectively, for changing the valve characteristics of the intake and exhaust valves;
Provided at the coaxial end of either the intake side or exhaust side camshaft to drive either the intake side or exhaust side variable valve means, and through the transmission means, the intake air Driving means for driving the variable valve means on the other side of the exhaust side or the exhaust side;
A valve state detection means for said drive means at the intake side or coaxially of the other of the cam shaft of the exhaust side is provided at the end of the same side as said end portion provided for detecting the other of the valve characteristic state,
An operating state detecting means for detecting an operating state of the internal combustion engine;
And a control means for controlling the operation of the drive means based on outputs of the valve state detection means and the operation state detection means. The variable valve operating apparatus according to claim 1,
The transmission means is composed of a plurality of gears meshing with each other, and is disposed between the drive means and the valve state detection means.
A variable valve operating apparatus characterized by that. The variable valve operating apparatus according to claim 2,
The drive means and the valve state detection means are provided at the respective end portions of the intake side and exhaust side camshafts so as to be relatively rotatable, and are connected to the intake side and exhaust side variable valve means. It is attached to the intake side and exhaust side camshafts via a rotating cylinder,
The transmission means is provided to connect the rotary cylinders on the intake side and the exhaust side.
A variable valve operating apparatus characterized by that. The variable valve operating apparatus according to any one of claims 1 to 3,
The transmission means is disposed on the same side in the camshaft axial direction as the end where the driving means is provided.
A variable valve operating apparatus characterized by that.

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