JPH1089019A - Valve overlap regulating system for vehicular engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce manufacturing cost, and regulate valve overlap easily. SOLUTION: A clutch means is provided with electron clutches 19, 21, and a camshaft fluctuation adjuster is provided with a reversible motor 25 which is controlled by an electronically controlled unit and having a driving shaft, a motor gear 27 connected to the driving shaft, a camshaft gear arranged on a camshaft 13, and more than one planetary gears 31, 33, 35 which are engaged with the motor gear 27, selectively engaged with the camshaft gear according to a rotational direction of a motor so as to rotate a camshaft which is not connected to a sprocket, and for regulating an overlap thereby. The camshaft fluctuation adjuster is provided with an elastic member for positioning the planetary gears 31, 33, 35 to an initial position again when the motor is not operated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a valve overlap adjustment system, and more particularly, to a valve overlap adjustment system used for changing the angle of an engine camshaft in a motor vehicle.

[0002]

2. Description of the Related Art Generally, valve timing and duration of valve opening are determined by the degree of rotation of a crankshaft. In the valve timing, there is a time when the exhaust valve is kept open and the intake valve is open for a short time, which is called valve overlap. That is,
The end of the exhaust stroke and the beginning of the intake stroke overlap for a short time. The valp overlap utilizes the inertial effect of the working mixture, thereby increasing the intake of the mixture in the cylinder and reducing the displacement. In particular, at large overlaps, some of the exhaust gas will remain in the cylinder with the fresh mixture. This results in the lowest combustion point temperature being obtained, thus lower nitrogen oxide emissions.

[0003]

The overlap is as follows:
It is usually regulated by a variable timing belt using a hydraulic system as the power source. Further, since the hydraulic system uses a hydraulic circuit, the structure of the variable timing belt system becomes complicated, and the manufacturing cost increases.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems, and an object of the present invention is to provide a valve overlap adjusting apparatus which is inexpensive to manufacture and can easily adjust the valve overlap. It is to provide a system.

[0005]

In order to achieve the above object, the present invention provides a clutch means provided between a camshaft and a sprocket so that the camshaft is not selectively connected to the sprocket. The camshaft variation adjuster adjusts the position of the camshaft when the camshaft is not connected to the sprocket by the clutch means. The clutch means and the camshaft variable adjuster are controlled by an electronic control unit according to the speed of the vehicle.

[0006] More preferably, the clutch means includes an electronic clutch. The camshaft variable adjuster is controlled by an electronic control unit, and is configured to mesh with a reversible motor having a drive shaft, a motor gear connected to the drive shaft, a camshaft gear installed on the camshaft, and the motor gear. And two or more planetary gears selectively meshed with the camshaft gear according to the rotation direction of the motor to rotate the camshaft not connected to the sprocket, thereby adjusting the overlap. The camshaft variation adjuster further includes an elastic member for repositioning the planetary gear at the initial position when the motor is not operating.

[0007]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The same reference numerals indicate the same or similar parts in all the drawings. FIG. 1 shows a block diagram of a valve overlap adjusting system according to a preferred embodiment of the present invention. The valve overlap adjusting system according to the present invention provides an engine RPM sensor 1 for detecting an engine RPM of an automobile.
And electronic clutches 19 and 21, a camshaft change adjuster 9 for adjusting the angle of the camshaft, and electronic clutches 19 and 21 in response to a signal from the engine RPM sensor 1.
21 and an electronic control unit 3 for controlling the operation of the camshaft fluctuation adjuster 9.

As shown in FIGS. 2 and 3, the electronic clutches 19 and 21 are installed at one end of the intake camshaft 11 and one end of the exhaust camshaft 13 provided adjacent to the sprockets 15 and 17, respectively. The intake camshaft gear 37 and the exhaust camshaft gear 39 are connected to the intake camshaft 11 and the exhaust camshaft 1.
3 at each other end. The camshaft variable adjuster 9 is selectively connected to the intake camshaft gear 37 and the exhaust camshaft gear 39.

The cam shaft change adjuster 9 includes a reversible motor 25, a motor gear 27 connected to a drive shaft of the motor so as to be driven by the motor 25, and first, second, and third gears meshing with the motor gear 27. Third planetary gear 3
1, 33, 35, the first, second, and third planetary gears 31, 33, 35 are interconnected by a connector 29, and the connector 29 has a second planetary gear 33 at both ends thereof.
And a third planetary gear 35 are rotatably installed, and a middle part of the horizontal member 291 is rotatably installed on the drive shaft.
And one end is rotatably connected to the drive shaft and the other end is
A vertical member 292 on which the planetary gear 31 is rotatably installed.

That is, the first planetary gear 31 is
Are arranged so as to be selectively meshed with the intake camshaft gear 37 or the exhaust camshaft gear 39 in accordance with the rotation direction of the motor 25. Further, the second and third planetary gears 33 and 35 rotate the motor 25. The intake camshaft 37 and the exhaust camshaft 39 are arranged so as to be selectively meshed with each other according to the direction. Preferably, the motor 25 is a stepper motor.

Also, when the motor 25 is not operating, the first, second, and third planetary gears 31, 33, and 35 are prevented from engaging with the intake camshaft gear 37 and the exhaust camshaft gear 39, respectively. An elastic member such as a tension spring 41 is provided, which is fixed to a suitable portion of the engine and the other end is fixed to both sides of the horizontal member 291. That is, when the motor 25 does not operate, the first, second, and third planetary gears 31, 33, and 35 return to the initial position (neutral position) by the tension spring 41.

In the above system, when a signal requesting the adjustment of the overlap between the intake valve and the exhaust valve (not shown) is transmitted from the engine RPM sensor 1 to the electronic control unit 3, the electronic control The unit 3 controls the electronic clutches 19 and 21 so that the sprockets 15 and 17 are not connected to the intake camshaft 11 and the exhaust camshaft 13, respectively. The electronic control unit 3 further controls the motor 25 so as to drive the motor gear 27 clockwise in the drawing. Therefore, the first, second, and third planetary gears 31, 33, 35 rotate clockwise around the motor gear 27, thereby causing the first and second planetary gears 31, 33 to rotate the intake camshaft gear 3,
7 and the exhaust camshaft gear 39.

In this state, when the motor gear 27 further rotates clockwise, the first planetary gear 31 and the second planetary gear 31
The planetary gears 33 rotate clockwise with respect to their axes, so that the intake camshaft gear 37 and the exhaust camshaft gear 3
9 rotates clockwise at a predetermined angle, whereby the intake camshaft 11 and the exhaust camshaft 13 rotate clockwise to adjust the overlap.

After completing the adjustment of the overlap, the electronic control unit 3 controls the motor 25 to stop, and further connects the intake camshaft 11 and the exhaust camshaft 13 with the sprockets 15 and 17 respectively connected thereto. The electronic clutches 19 and 21 are controlled as described above. The motor 2
When the gear 5 stops, the planetary gears 31, 33, 35 are returned to the initial position (neutral position) by the tension spring 41, so that the engagement with the intake camshaft gear 37 and the exhaust camshaft gear 39 is released.

Thereafter, a signal requesting that the adjusted overlap return to the initial state is output by the engine RPM sensor 1.
Is transmitted to the electronic control unit 3, the electronic control unit 3 controls the electronic clutches 19 and 21 so that the sprockets 15 and 17 are not connected to the respective intake camshafts 11 and exhaust camshafts 13. The electronic control unit 3 further controls the motor 25 so as to drive the motor gear 27 in a clockwise direction in the drawing. Therefore, the first, second, and third planetary gears 31, 33, 3
5 rotates clockwise around the motor gear 27, whereby the first and third planetary gears 31 and 35 mesh with the intake camshaft gear 37 and the exhaust camshaft gear 39, respectively.

In this state, when the motor gear 27 further rotates clockwise, the first and third planetary gears 31, 35 rotate clockwise with respect to their axes.
Therefore, the intake camshaft gear 37 and the exhaust camshaft gear 39
Rotate clockwise at a predetermined angle, whereby the intake camshaft 11 and the exhaust camshaft 13 rotate clockwise, and the overlap returns to the initial state.

After completing the return of the overlap, the electronic control unit 3 controls the motor 25 to stop, and connects the intake camshaft 11 and the exhaust camshaft 13 to the sprockets 15 and 17 respectively connected thereto. The electronic clutches 19 and 21 are controlled so as to cause them to operate. When the motor 25 stops, the first, second, and third planetary gears 3
1, 33 and 35 are returned to the initial position (neutral position) by the tension spring 41 so that the engagement with the intake camshaft gear 37 and the exhaust camshaft gear 39 is released.

The above embodiment is an example of the present invention applied to a double overhead camshaft of an engine. However, the invention can be applied to a single overhead camshaft of an engine.

FIGS. 4 and 5 show another embodiment in which the present invention is applied to a single overhead camshaft. As shown, a single camshaft 12 is provided, and an electronic clutch 20 is disposed between the sprocket 16 and the single camshaft 12. Also, the camshaft gear 3
8 is installed at one end of the single camshaft 12. Further, the camshaft variable adjuster 10 is selectively connected to the camshaft gear 38.

The camshaft variable adjuster 10 includes a reversible motor 24 and a motor gear 26 connected to a drive shaft of the motor 24 so as to be driven by the motor 24.
And first and second planetary gears 32, 34 meshing around the motor gear 26, the first and second planetary gears 32, 34 are interconnected by a connector 28, and the connector 28 First, which is arranged at a predetermined angle and is rotatably connected to a drive shaft of the motor 24;
It has second members 281 and 282. The planetary gear 32,
34 is installed at one end of each of the first and second members 281 and 282. That is, the first and second planetary gears 32 and 34
Are arranged so that they can be selectively engaged with the camshaft gear 38 according to the rotation direction of the motor 24.

Further, an elastic member such as the tension spring 40 is provided.
Is fixed at one end to an appropriate position of the engine and the other end to prevent the first and second planetary gears 32 and 34 from meshing with the camshaft gear 38 when the motor 24 is not operating. Are the first and second members 281, 2 respectively.
82. That is, if the motor 24 does not operate,
The first and second planetary gears 32 and 34 are returned to their initial positions (neutral positions) by the tension spring 40.

In this embodiment, the electronic clutch 20
The adjuster 10 is further controlled by the electronic control unit 3. A signal requesting the adjustment of the overlap between the intake valve and the exhaust valve (not shown) is given by RPM.
When transmitted from the sensor 1 to the electronic control unit 3, the electronic control unit 3 controls the electronic clutch 20 so that the sprockets 15 and 17 are not connected to the respective intake camshafts 11 and exhaust camshafts 13. The electronic control unit 3 further controls the motor 24 so as to operate the motor gear 26 clockwise in the drawing. So,
The first and second planetary gears 32 and 34 rotate clockwise around the motor gear 26, whereby the first planetary gear 32 meshes with the camshaft gear 38.

In this state, when the motor gear 26 further rotates clockwise, the first planetary gear 32 rotates clockwise with respect to its axis, and the camshaft gear 38 rotates clockwise at a predetermined angle. Thereby, the camshaft 12 is rotated clockwise to adjust the overlap.

After completing the overlap adjustment, the electronic control unit 3 controls the motor 24 to stop, and further controls the electronic clutch 20 to connect the camshaft 12 to the sprocket 16. When the motor 24 stops, the first and second planetary gears 32 and 34 are returned to their initial positions (that is, neutral positions) by the tension springs 40 so as not to mesh with the camshaft gears 38.

Thereafter, when a signal requesting feedback of the adjusted overlap to the initial state is transmitted from the RPM sensor 1 to the electronic control unit 3, the electronic control unit 3
The electronic clutch 20 is controlled so that the sprocket 16 is not connected to the camshaft 12. The electronic control unit 3
Further, the motor 24 is controlled so as to drive the motor gear 26 in the clockwise direction in the drawing. So, first,
The second planetary gears 32, 34 rotate in a clockwise direction around the motor gear 26, whereby the second planetary gear 34 meshes with the camshaft gear 38.

In this state, when the motor gear 26 further rotates clockwise, the second planetary gear 34 rotates clockwise with respect to its axis, and the camshaft gear 38 rotates clockwise at a predetermined angle. As a result, the cam shaft 12 rotates clockwise, and the overlap returns to the initial state.

After the completion of the overlap feedback, the electronic control unit 3 controls the motor 25 to stop and controls the electronic clutch 20 to connect the camshaft 12 to the sprocket 16 connected thereto. When the motor stops, the first and second planetary gears 32 and 34 are returned to their initial positions (that is, neutral positions) by the tension spring 40 so as not to mesh with the camshaft gear 38.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications may be made within the scope of the claims, the detailed description of the invention, and the accompanying drawings. It is apparent that the present invention can be embodied in various forms, and this is also within the scope of the present invention.

[0029]

As described above, in the system of the present invention, the relative movement between the sprocket and the camshaft can be easily operated using a motor or the like, so that it is easy to adjust the overlap section. There are advantages. In addition, since the hydraulic circuit is not used, the structure is simplified, and there is an advantage that the unit price of the product is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a valve overlap adjustment system according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a valve overlap adjustment system according to the first embodiment of the present invention.

FIG. 3 is a side view showing a camshaft fluctuation adjuster according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing a valve overlap adjusting system according to a second embodiment of the present invention.

FIG. 5 is a side view showing a camshaft fluctuation adjuster according to a second embodiment of the present invention.

[Description of Signs] 1 Engine RPM sensor 3 Electronic control unit 9 Camshaft fluctuation adjuster 10 Camshaft fluctuation adjuster 11 Intake camshaft 12 Single camshaft 13 Exhaust camshaft 15 Sprocket 16 Sprocket 17 Sprocket 19 Electronic clutch 20 Electronic clutch 21 Electronic clutch 24 reversible motor 25 reversible motor 26 motor gear 27 motor gear 28 connector 31 first planetary gear 32 first planetary gear 33 second planetary gear 34 second planetary gear 35 third planetary gear 37 intake camshaft gear 38 camshaft gear 39 exhaust camshaft Gear 40 Tension spring 41 Tension spring 281 First member 282 Second member 291 Horizontal member 292 Vertical member

Claims (8)

[Claims] 1. A valve overlap adjusting system for a vehicle engine having a camshaft connected to a sprocket, a clutch means for preventing the camshaft from being selectively connected to a corresponding sprocket, and the clutch. A camshaft variable adjuster for adjusting the position of the camshaft when the camshaft is not connected to the sprocket by means; and an electronic control unit for controlling the clutch means and the camshaft variable adjuster according to the speed of the vehicle. A valve overlap adjusting system for a vehicle engine. 2. The valve overlap adjusting system for a vehicle engine according to claim 1, wherein said clutch means includes an electronic clutch. 3. A reversible motor controlled by the electronic control unit and having a drive shaft, a motor gear connected to the drive shaft, a cam shaft gear installed on the cam shaft, And two or more planetary gears meshing with the motor gear and selectively meshing with the camshaft gear according to the rotation direction of the motor so as to rotate the camshaft not connected to the sprocket, thereby adjusting the overlap. The valve overlap adjusting system for a vehicle engine according to claim 1, comprising: 4. The camshaft fluctuation adjuster further comprises:
4. The valve overlap adjusting system for a vehicle engine according to claim 3, further comprising an elastic member for repositioning the planetary gear at the initial position when the motor is not operating. 5. A valve overlap adjusting system for a vehicle double overhead camshaft engine having an intake camshaft and an exhaust camshaft respectively connected to an intake sprocket and an exhaust sprocket, wherein the first camshaft and the second camshaft are respectively provided. Clutch means for selectively preventing connection with the first and second sprockets to be connected; and when the intake camshaft and exhaust camshaft are not connected to the first and second sprockets by the clutch means, respectively. A vehicle comprising: a camshaft variable adjuster for adjusting the positions of an intake camshaft and an exhaust camshaft; and an electronic control unit for controlling the clutch means and the camshaft variable adjuster in accordance with the speed of the vehicle. Engine valve overlap adjustment system. 6. The valve overlap adjusting system for a vehicle engine according to claim 5, wherein the clutch means includes an intake electronic clutch and an exhaust electronic clutch connected to the intake camshaft and the exhaust camshaft. 7. The camshaft change adjuster is controlled by the electronic control unit, and is installed on a reversible motor having a drive shaft, a motor gear connected to the drive shaft, and an intake camshaft and an exhaust camshaft, respectively. An intake camshaft gear and an exhaust camshaft gear that mesh with the periphery of the motor gear, and rotate the intake camshaft and the exhaust camshaft that are not connected to the sprocket by clutch means according to the rotation direction of the motor. And selectively meshed with the exhaust camshaft gear,
The first and second to adjust the valve overlap thereby
The valve overlap adjusting system for a vehicle engine according to claim 5, further comprising a third planetary gear. 8. The camshaft variation adjuster further comprises:
The valve overlap adjusting system for a vehicle engine according to claim 7, further comprising an elastic member for repositioning the planetary gear to the initial position when the motor is not operating.