JP2000130197A - Variable valve system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge the freedom of design, in a variable valve system, by shortening the overall length of an internal combustion engine for restraining the interference with the peripheral equipment. SOLUTION: Nonconstant velocity universal couplings 14, 44 for changing the valve characteristics are provided between the cam shafts 11, 41 on the intake side and on the exhaust side and cam lobes 12, 42, and an actuator 51 for drivingly controlling the nonconstant velocity couplings 14, 44 is provided to the end part on the same shaft of the exhaust side cam shaft 41; on the other hand, a position sensor 31 for detecting the rotational phase and for detecting the valve characteristic conditions is provided to the end part on the same shaft of the intake side camshaft 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve system used for controlling the opening and closing of an intake valve and an exhaust valve of an internal combustion engine at a timing according to the operating state of the engine.

[0002]

2. Description of the Related Art Conventionally, in a valve train of an internal combustion engine,
Various devices have been proposed in which the opening / closing timing and opening time of the intake / exhaust valve can be changed. As such a device, for example, a non-constant velocity joint is interposed between a cam and a camshaft, and the cam is rotated relative to the camshaft through the non-constant velocity joint, and the cam is disengaged from the camshaft. An apparatus has been proposed in which the valve is rotated at different speeds so that the valve opening / closing timing and the opening time can be adjusted. As such, Japanese Patent Application Laid-Open No. 9-2800
No. 24 is disclosed.

[0003]

Incidentally, the above-described variable valve apparatus requires an actuator for simultaneously adjusting the valve opening / closing timing and the 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 required. For this reason, Japanese Unexamined Patent Application Publication No. 9-28002
In the variable valve mechanism described in Japanese Patent Application Publication No. 4 (1994), an actuator in which this sensor is integrally provided is provided at an end of a camshaft.

However, when an actuator having a sensor integrally provided at the end of the camshaft is mounted, as in the variable valve mechanism disclosed in this publication, the entire length of the engine is increased and interferes with peripheral devices in the engine room. However, there is a problem that the degree of freedom in design is reduced. In particular, when this structure is applied to an engine with a large displacement, the above-described problem will be prominent.

SUMMARY OF THE INVENTION The present invention solves such a problem, and a variable valve train capable of shortening the total length of an internal combustion engine, suppressing interference with peripheral devices, and increasing the degree of freedom in design. The purpose is to provide.

[0006]

A variable valve apparatus according to the present invention for achieving the above object is rotatably provided on an intake side and an exhaust side of an internal combustion engine, and receives a driving force from a crankshaft. A pair of camshafts, variable valve means respectively provided on the intake-side and exhaust-side camshafts to change valve characteristics of intake and exhaust valves, and one of the intake-side and exhaust-side cams A driving means provided at a coaxial end of a shaft for driving one of the variable valve operating means on the intake side and the exhaust side to change one valve characteristic, and the one driven by the driving means Transmitting means for transmitting the driving force of the variable valve operating means to the other variable valve operating means, and detecting the other valve characteristic state provided at the coaxial end of the other camshaft on the intake side or the exhaust side. Valve state detecting means Operating state detecting means for detecting an operating state of the internal combustion engine; and control means for controlling operation of the driving means based on outputs of the valve state detecting means and the operating state detecting means. Things.

Accordingly, the drive means is provided at the coaxial end of either the intake side or the exhaust side camshaft, and the valve state detecting 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 of the camshaft, so that interference between the internal combustion engine and peripheral devices is suppressed, and the degree of freedom in design can be increased.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of a variable valve operating apparatus according to one embodiment of the present invention, and FIG. 2 shows a variable valve timing characteristic of the variable valve operating apparatus of this embodiment.

[0010] Each cylinder of the internal combustion engine is provided with an intake valve and an exhaust valve. Above the cylinder head, a valve mechanism for opening and closing these intake and exhaust valves is provided. This valve operating mechanism is configured as a variable valve operating mechanism capable of changing the opening / closing timing and opening time of an intake valve and an exhaust valve. In the present embodiment described below, a variable valve operating device of the present invention is a four-valve in-line four-in-line engine having two intake valves and two exhaust valves in each cylinder as an internal combustion engine.
A description will be given by applying the present invention to a cylinder engine.

In the variable valve apparatus according to this embodiment, FIG.
As shown in FIG. 1, an intake side camshaft 11 and an exhaust side camshaft 41, which are parallel to each other, are rotatably supported by a cylinder head (not shown).
Sprockets 61 are fixed to the ends of the sprockets 41, 41, and a pulley belt 62 is looped between each sprocket 61 and the crankshaft. Therefore, the rotational motion from the crankshaft is transmitted to each of the camshafts 11 and 41 via the pulley belt 62 and the sprocket 61.

Four cam lobes 12 are mounted on the intake camshaft 11 so as to be rotatable relative to each cylinder.
Each cam lobe 12 is formed with a pair of cams 13. Then, the camshaft 11 and the cam lobe 12
A non-constant velocity joint 14 as variable valve operating means for transmitting the rotational speed of the camshaft 11 to the cam lobe 12 at an irregular velocity is provided between the two. On the other hand, a pair of intake valves 15 for opening and closing intake ports are provided in the cylinder head for each cylinder, and a roller rocker arm 16 is provided at the upper end of each intake valve 15. Therefore, when the rotational speed of the camshaft 11 is transmitted at irregular speed to the cam lobe 12 through the irregular speed joint 14, the cam 13 of the cam lobe 12 is moved via the roller rocker arm 16 to the intake valve 15.
Can be opened and closed by changing the opening / closing timing and opening time of the intake port.

On the other hand, four cam lobes 42 are similarly mounted on the exhaust side camshaft 41 corresponding to the respective cylinders so as to be relatively rotatable, and each of the cam lobes 42 is formed with a pair of cams 43. Further, between the camshaft 41 and the cam lobe 42, a non-constant velocity joint 44 for transmitting the rotation speed of the camshaft 11 to the cam lobe 42 at an irregular speed is provided. On the other hand, a pair of exhaust valves 45 for opening and closing an exhaust port are provided for each cylinder in the cylinder head, and a roller rocker arm 46 is provided at the upper end of each exhaust valve 45.

Here, the camshafts 11 and 41, the cam lobes 12 and 42, the non-constant velocity joints 14 and 44, etc. will be described in detail. The intake side and the exhaust side have substantially the same configuration. The configuration on the intake side will be described, and the description on the configuration on the exhaust side will be omitted.

The camshaft 11 on the intake side is rotatable relative to the camshaft 11.
A pair of cams 13 are formed in the mounted cam lobe 12.
And the flange portion 17
Is formed, and an engagement hole 18 is formed in the flange portion 17.
Have been. On the other hand, the camshaft 11 has an eccentric portion 19.
Eccentric control gear 20 is mounted so as to be relatively rotatable.
The eccentric ring 21 can rotate relative to the outer periphery of the eccentric part 19
It is attached to. That is, during rotation of the camshaft 11
Heart O₁, The rotation center O of the eccentric ring 21 _TwoIs prescribed
Both are arranged so as to be eccentric by the amount m.
Then, one end face of the eccentric ring 21 is 180
° Notches 22 and 23 are formed at opposing positions.

Cam lobe 12 on camshaft 11
An operating arm 24 is fixed at a position between the eccentric ring 21 and the eccentric ring 21, and an engaging hole 25 is formed at a distal end in the radial direction. The base end of the first slider 26 is fitted into the engagement hole 25 of the operation arm 24, and the front end of the first slider 26 is engaged with one notch 22 of the eccentric ring 21. Further, the base end of the second slider 27 fits into the engagement hole 18 formed in the flange portion 17 of the cam lobe 12, and
The tip of the second slider 27 is engaged with the other notch 23 of the eccentric ring 21.

As described above, the eccentric ring 21, the operating arm 24, the sliders 26, 27, and the like are interposed between the camshaft 11 and the cam lobe 12 as the non-constant velocity joint 14, thereby rotating the camshaft 11. Eccentric ring 2 for
1 and the cam lobe 12 repeat the operation of leading or delaying, and the cam lobe 12 rotates at an uneven speed with respect to the camshaft 11.

A rotary cylinder 28 is rotatably fitted to an end of the camshaft 11 opposite to the sprocket 61, and a transmission gear 29 and a control gear 30 are mounted on the rotary cylinder 28. . At the end of the rotary cylinder 28, a position sensor 31 as a valve state detecting means is attached. 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 3 adjacent to and parallel to the camshaft 11
2 is rotatably supported by the cylinder head. A connection gear 33 meshing with the control gear 30 and a connection gear 34 meshing with each eccentric control gear 20 are attached to the control shaft 32.

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.
Is mounted with a transmission gear 49 and a control gear 50. An actuator 51 as a driving means is attached to an end of the rotary cylinder 48. This actuator 5
Reference numeral 1 denotes a hydraulic actuator, which reciprocates the control gear 50 by controlling the control valve of a hydraulic supply device (not shown) to adjust the supply state of the hydraulic oil. A control shaft 52 adjacent to and parallel to the camshaft 41 is rotatably supported by the cylinder head. This control shaft 52 has a control gear 50
And a connecting gear 54 meshing with each eccentricity control gear 47 are attached.

Between the transmission gear 49 on the exhaust side and the transmission gear 29 on the intake side, a transmission gear mechanism 63 composed of a plurality of gears meshing with each other is disposed as transmission means. Therefore, 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 connection gear 53, and the transmission gear 49, the transmission gear mechanism 63, and the transmission gear 2 are rotated.
9, the control cylinder 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. I do.

Here, the operation of the variable valve apparatus of this embodiment, that is, the rotation phase of the eccentric ring 21 and the cam lobe 12 with respect to the rotation phase of the camshaft 11 (camshaft rotation angle) will be described, and the valve opening / closing timing and opening will be described. The change of the period will be specifically described. Here, only the intake side will be described.

As shown in FIG. 2, the camshaft angle is 0
In the °, when the rotation center O ₂ of the eccentric ring 21 with respect to the rotation center O ₁ of the camshaft 11 is in the low speed position eccentric downward, to connect the cam lobe 12 and the actuating arm 24 and the eccentric ring 21 2 The two sliders 26 and 27 are on a straight line passing through the rotation centers O ₁ and O ₂ . First, the camshaft 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 13 of the cam lobe 12 is delayed by φ _L, so that the cam shaft 11 The cam 13 rotates at a lower speed than the rotation.

Next, the camshaft 11 is moved from 90 ° to 18 °.
When rotated to 0 °, 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.

Further, when the camshaft 11 is moved from 180 ° to 2
When rotated to 70 °, the rotation angle θ _{A of the} camshaft 11
The rotation angle θ _D of the eccentric ring 21 becomes larger by θ _F than that of the cam shaft 11 and the cam 13 of the cam lobe 12 is advanced by φ _F, so that the cam 13 rotates at a higher speed than the rotation of the cam shaft 11.

When the camshaft 11 rotates from 270 ° to 360 ° (= 0 °), the camshaft 11
The rotation angle θ _E of the eccentric ring 21 becomes smaller than the rotation angle θ _{A of} the cam shaft 11, and the cam 13 rotates at a lower speed than the rotation of the cam shaft 11.

With such a configuration, the camshaft 11
By moving the cam lobe 12 ahead or behind, the camshaft 11 can rotate at an irregular speed. That is, as described above, the camshaft 11
When the cam 13 is delayed when rotating from 90 ° to 90 °, the valve opening timing of the intake valve 15 is delayed. When the camshaft 11 rotates from 180 ° to 270 °, the advance of the cam 13 causes the intake air to be taken. Since the closing timing of the valve 15 is advanced, the opening time is shortened.

By the way, the cam for the camshaft 11
The phase shift of the lobe 12 (cam 13) is determined by the camshaft.
Rotation center O of G11₁The eccentric ring 21 is rotating
Heart O _TwoCan be changed by changing the position of. One
In other words, the actuator 51 is driven to rotate the rotating cylinder 4 on the exhaust side.
8, through the control gear 50 and the connecting gear 53,
While rotating the trolley shaft 52, the transmission gear 4
9, transmission gear mechanism 63, transmission gear 29, rotary cylinder 28,
Control gear 30 and control gear 33
When the shaft 32 is rotated, the connecting gears 34 and 54
The eccentricity control gears 20 and 47 are rotated through the eccentricity control gears.
The eccentric part 19 integrated with the gears 20 and 47 rotates to form an eccentric ring.
21 and the rotation center O of the camshaft 11₁Against
Center O of the eccentric ring 21_TwoCan change the position of
it can.

Then, as shown in FIG. 2, when the camshaft angle is 0 °, the rotation center O _{1 of the} camshaft 11 is set.
From the position where the rotation center O ₂ of the eccentric ring 21 is eccentric upward at a high speed position,
When the cam shaft 11 rotates, the cam 13 advances to the cam 13 to generate φ _F , so that the cam 13 rotates at a higher speed than the rotation of the cam shaft 11. Next, the camshaft 1
When 1 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 camshaft 1
The rotation speed of the cam 13 is lower than that of the first rotation. Then, when the camshaft 11 rotates from 270 ° to 360 ° (= 0 °), the cam 13 rotates at high speed.

With such a configuration, the camshaft 11
When the rotation of the camshaft rotates from 0 ° to 90 ° and the advance of the cam 13 occurs, the valve opening timing of the intake valve 15 is advanced, and when the camshaft 11 rotates from 180 ° to 270 °, the cam 13 is delayed. Then intake valve 1
Since the valve closing timing of No. 5 is delayed, the opening time becomes long.

The change of the opening / closing timing and the opening time of the intake valve 15 is controlled by an electronic control unit (ECU) 71 as control means.
The ECU 71 outputs an output (N) of a crank angle sensor, a throttle position sensor, and the like as operating state detecting means.
e, TPS, etc.) and the drive control of the actuator 51 based on the rotational phase of the control gear 30 detected by the position sensor 31.

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 an end of the camshaft 11 on the intake side.
And an actuator 51 for changing valve characteristics (opening / closing timing and opening time of the intake valve 15) is provided at an end of the camshaft 51 on the exhaust side. Therefore, the overall length of the engine does not increase, and the position sensor 31 and the actuator 51 do not interfere with peripheral devices in the engine room, and the degree of freedom in design can be increased. In particular, when the structure according to the present embodiment is applied to an engine having a large displacement, the above-described effects are remarkably exhibited.

Further, the provision of the position sensor 31 on the camshaft 11 on the intake side makes it possible to accurately detect and control the operation of each mechanism of the intake system, thereby ensuring a high output.

In the above embodiment, the position sensor 31 is provided on the camshaft 11 on the intake side, and the actuator 51 is provided on the camshaft 41 on the exhaust side. However, contrary to the present embodiment, the position sensor 31 is provided on the intake side. An actuator 51 is provided on the camshaft 11, and the camshaft 41 on the exhaust side is provided.
May be provided with a position sensor 31. In this case, since the operation of each mechanism on the exhaust valve side can be detected with high accuracy, it is possible to accurately control the internal EGR remaining in the combustion chamber and adjust the exhaust gas temperature by controlling the opening timing of the exhaust valve. There is an effect that can be achieved. In the above-described embodiment, the variable valve 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]

As described in detail in the above embodiments, according to the variable valve operating device of the present invention, the overall length of the internal combustion engine is shortened without increasing the overall length of the camshaft. By suppressing interference with peripheral devices, the degree of freedom in design can be increased.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a variable valve apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating variable valve timing characteristics of the variable valve apparatus of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Intake side camshaft 12 Cam lobe 13 Cam 14 Variable velocity joint (variable valve operating means) 15 Intake valve 21 Eccentric ring 24 Operating arm 26 First slider 27 Second slider 31 Position sensor (Valve state detecting means) 41 Exhaust side cam Shaft 42 Cam lobe 43 Cam 44 Variable velocity joint (variable valve means) 45 Exhaust valve 51 Actuator (Drive means) 63 Transmission gear mechanism (Transmission means) 71 Electronic control unit, ECU (Control means)

Claims (1)

[Claims] 1. A pair of camshafts rotatably provided on an intake side and an exhaust side of an internal combustion engine to transmit a driving force from a crankshaft, and provided on a camshaft on the intake side and an exhaust side, respectively. A variable valve means for changing valve characteristics of an intake valve and an exhaust valve; and one of the intake side and the exhaust side provided at a coaxial end of one of the camshafts on the intake side and the exhaust side. A driving means for driving one variable valve means to change one valve characteristic, and a transmission means for transmitting a driving force of the one variable valve means driven by the driving means to the other variable valve means. A valve state detecting means provided at a coaxial end of the other camshaft on the intake side or the exhaust side to detect the other valve characteristic state, and an operating state detecting means for detecting an operating state of the internal combustion engine; , The valve status inspection Control means for controlling the operation of the driving means based on the output of the output means and the operation state detecting means.