Patent Application
20130092110
The present application claims priority of Korean Patent Application Number 10-2011-0106602 filed Oct. 18, 2011, the entire contents of which application is incorporated herein for all purposes by this reference.
1. Field of Invention
The present invention relates to an engine of a vehicle, and more particularly, to a continuously variable valve lift apparatus.
2. Description of Related Art
Generally, an automotive engine includes a combustion chamber in which fuel burns to generate power. The combustion chamber is provided with an intake valve for supplying a gas mixture containing the fuel and an exhaust valve for expelling burned gas. The intake and exhaust valves open and close the combustion chamber by a valve lift apparatus connected to a crankshaft.
A conventional valve lift apparatus has a fixed valve lift amount using a cam formed in a predetermined shape. Therefore, it is impossible to adjust the amount of a gas that is being introduced or exhausted. Therefore, the engine does not run at its optimum state in various driving ranges.
For example, if a valve lift apparatus is designed to optimally respond to a low driving speed, the valve open time and amount are not sufficient for a high speed driving state. On the contrary, when the valve lift apparatus is designed to optimally respond to a high speed driving state, an opposite phenomenon occurs in the low speed driving state.
To improve the above situation, a continuous variable valve lift (hereinafter, “CVVL”) apparatus is applied to adjust valve lift. The CVVL according to a conventional art includes a control shaft that is disposed on a journal that is disposed on a cam carrier, and a CVVL device that is disposed on the control shaft.
However, because the conventional CVVL has a control shaft disposed on the journal, the operation of the CVVL device can be interfered with by a friction resistance between the journal and the control shaft.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Various aspects of the present application are directed to provide a continuously variable valve lift (CVVL) apparatus and an engine comprising a CVVL apparatus. An engine with a CVVL apparatus has advantages of suppressing the operational interference of a CVVL device that is caused by friction between a journal and a control shaft, improving the operability of the CVVL device, and reducing operational noise of the CVVL.
Various aspects of the present invention provide for an engine having a continuously variable valve lift (CVVL) apparatus that may include a control shaft that is disposed in parallel with a camshaft and is rotatably disposed on a journal that is disposed on a cam carrier, a CVVL device that is disposed on the control shaft, a journal bearing that is disposed on the journal such that the control shaft rotates on the journal bearing, and a washer that is disposed on the control shaft across the journal bearing.
One side of the washer may contact the CVVL device and the other side thereof contacts the journal bearing such that the gap between the CVVL device and the journal bearing can be uniformly maintained, wherein the washer is a wave type, and the change variation of the washer ranges from about 1.9 to about 2.3 mm.
The journal bearing may be fixed on the journal through a cam cap.
The journal bearing that is mounted on the journal may suppress friction between the control shaft and the journal during operation of the CVVL device.
The journal bearing may be disposed and the wave washer is disposed at both side of the journal bearing to be mounted on the control shaft such that the gap between the CVVL device and the journal bearing is uniformly maintained, although the journal bearing is compressed by the cam cap.
Mutual interference between the CVVL device and the journal bearing may be prevented and thus the operating performance of the CVVL device is improved.
Also, the gap between the CVVL device and the journal bearing may be uniformly maintained in various embodiments of the present application to suppress the operational noise that is generated when the CVVL device moves.
The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.
Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.
In order to clarify the present application, parts that are not connected with the description will be omitted, and the same elements or equivalents are referred to with the same reference numerals throughout the specification. Also, the size and thickness of each element shown in the drawings are exemplary; the present application is not necessarily limited thereto. In the drawings, the thickness of layers, films, panels, regions and other components are not drawn in proportion; some are exaggerated for clarity.
Referring to
The control shaft 10 is disposed in parallel to a camshaft 5, which is generally referred to as “drive shaft,” to be rotatably mounted on a cam carrier 3. Here, the control shaft 10 is mounted on a journal 11 that is prepared on the cam carrier 3 to be able to be operated by an actuator 90 that is mounted on the cam carrier 3. The journal 11 for supporting the control shaft 10 is formed with a semicircular groove.
The CVVL device 30 is prepared on the control shaft 10, as is well known to a person skilled in the art, and therefore the detailed description thereof will be omitted in this application.
The journal bearing 50 is disposed on the semicircular groove of the journal 11 to rotatably support the control shaft 10. For example, the journal bearing 50 can include a needle bearing. The journal bearing 50 can suppress the friction between the control shaft 10 and the journal 11 during the operation of the CVVL device 30. Here, the journal bearing 50 is compressed by a cam cap 15 and can be fixed by the journal 11 thereof. The cam cap 15 can be engaged with the journal 11 through a fastening member such as a bolt.
In various embodiments of the present application, a washer 70 is used to maintain a gap between the CVVL device 30 and the journal bearing 50. That is, the washer 70 fixes the position of the journal bearing 50 that is applied to the journal 11 to maintain the position of the journal bearing 50 and can adjust the gap between the CVVL device 30 and the journal bearing 50.
The washer 70 can be disposed on the control shaft 10 in a condition that the journal bearing 50 is disposed between the journal and the washer 70. For example, the washer 70 according to various embodiments of the present application, as shown in
The wave washer 71 has a pressure absorption displacement ranging from about 1.9 to about 2.3 through the wave shape, the width is about 2 3 mm in a free condition, and the width is about 1.9 mm in a mounted condition.
Accordingly, in the engine 1 having a continuously variable valve lift apparatus 100, the journal bearing 50 is disposed and the wave washer 71 is disposed at both sides of the journal bearing 50 to be mounted on the control shaft 10 such that the gap between the CVVL device 30 and the journal bearing 50 is uniformly maintained, although the journal bearing 50 is compressed by the cam cap 15.
That is, through the wave washer 71 that adjusts compression force applied to the journal bearing 50 in various embodiments of the present application, the position of the journal bearing 50 that is applied to the journal 11 is uniformly maintained and the gap between the CVVL device 30 and the journal bearing 50 can be controlled.
Thereby, mutual interference between the CVVL device 30 and the journal bearing 50 in various embodiments of the present application is prevented and accordingly the operating performance of the CVVL device 30 is improved.
Also, the gap between the CVVL device 30 and the journal bearing 50 is uniformly maintained in various embodiments of the present application to suppress operational noise that is generated when the CVVL device 30 moves.
Referring to
As described above, the width of the washer is about 2.3 mm in a free condition in which the washer is not mounted, and the width of the washer can be reduced to about 1.9 mm in a condition that the washer is mounted between the CVVL device 30 and the journal bearing 50.
That is, the gap between the CVVL device and the journal bearing can be adjusted in a range from about 1.9 to about 2.3 mm in various embodiments of the present application.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2011-0106602 | Oct 2011 | KR | national |
