VARIABLE VALVE TIMING DEVICE WITH ECCENTRIC VALVE ACTUATOR SLEEVES
Variable valve timing apparatus includes eccentric valve actuator sleeves which surrounds each of the valve actuators. In a preferred embodiment, the pivoting sleeves act to change the position of the valve actuator axis related to the camshaft axis. In combination with roller style cam follower, a movement of the actuator axis in camshaft rotation direction it causes a delayed valve operation, meantime a movement of the actuator axis towards the camshaft rotation direction it causes a advanced valve operation mode.
The invention relates to a valve actuator arrangement in internal combustion engines. In particular, the invention pertains to pivoting, eccentric valve actuator sleeves with lever arms. By its use, the valve timing in internal combustion engines can be varied.
The aforementioned system has the fundamental concept of making it possible to regulate the valve timing in an internal combustion engine with camshaft-in-block valvetrain layout, such as the traditional American style V6, V8 and V10 engines. Engines with variable valve drive have major advantages over “normal” engines. They have excellent running properties over the entire rpm range. Both pollutant emissions and fuel consumption can be reduced considerably. Because the valve control times are designed to be regulatable, higher outputs can be attained even with smaller engine displacement.
US Patent 2008/223321 discloses a valve system which allow a secondary valve event to be enabled or disabled. U.S. Pat. No. 5,937,809 discloses a system in which the valve timing are variable by the rotation of the rocker arm about the camshaft. US Patent 2007/000459 show a roller actuator with integrated deactivating device. U.S. Pat. No. 5,664,463 discloses a assembled style camshaft, in which shaft elements are positioned one inside the other. DE102009037976 discloses a camshaft hub for variable adjustment of valve timing.
BRIEF SUMMARY OF THE INVENTIONCompared to the prior art, the eccentric valve actuator sleeves during the rotatory switchover process from a initial leaver arm position to a changed leaver arm position it causes a circular motion of the valve actuator and corresponding a change of its position related to the camshaft axis. Dependent of the specific geometry and eccentricity of said sleeves, a movement of the valve actuator axis towards to the camshaft rotation direction can be achieved, or alternatively a movement of the valve actuator axis in camshaft rotation direction can be achieved. In combination with valve actuators with roller style cam follower a change of the valve actuator position towards camshaft rotation direction it causes a advanced valve operation, while a change of the valve actuator position in camshaft rotation direction it causes a retarded valve operation.
The invention is described below in terms of an exemplary embodiment in conjunction with the schematic drawings. The variant described is based for instance on a V-8 engine with a single camshaft which is located central into the engine block. The drawings show the following:
Referring to
In the illustrated embodiment the engine has two cylinder banks 18, and 20. Between said cylinder banks a lifter valley area 22 is located. In said area bores are located in which eccentric valve actuator sleeves 24, 26 are implemented to incorporate conventional hydraulic valve actuators 28 30, or optionally switchable hydraulic valve actuators 32. Both type of valve actuators are roller style cam followers and commonly used for camshaft in block engines.
A exemplary actuator device with exemplary two hydraulic actuators 34, 36 acts in conjunction with the linkage 38 to the lever arms 40 of the sleeves.
The arrangement in
In order to keep the valve actuators from rotating with the rotary sleeves, the upper portions of the actuator bodies are provided with flats, which are engaged by valve actuator guides. Both, intake valve actuators and exhaust valve actuators require a separate and independent guide device.
While the invention has been described by reference to certain preferred embodiments, it should be understood that numerous changes could be made within the spirit and scope of the inventive concepts described. For example, the variability of the described embodiment could be increased by the use of separate actuation devices for both, intake valve actuator sleeves and exhaust valve actuator sleeves. Also a detection of the pivoting position of the sleeves with sensors for determine a specific lever arm position and the corresponding resulting valve operation condition could be implemented. Accordingly, it is intended that the invention not be limited to the disclosed embodiments, but that it have the full scope permitted by the language of the following claims.
Claims
1. Variable valve timing apparatus for an internal combustion engine comprising:
- a engine block with a incorporated camshaft;
- a plurality of bores for receiving valve actuators;
- a plurality of valve actuators for actuating respective valves of the multiple cylinders; and
- eccentric valve actuator sleeves between each of the valve actuators and their respective bores, said eccentric valve actuator sleeves being rotatable between a initial position and a changed position wherein a rotatory movement of said eccentric valve actuator sleeves causes a change in position of the corresponding valve actuators related to the camshaft rotation axis.
2. Apparatus as in claim 1 wherein a rotatory movement of a plurality of said eccentric valve actuator sleeves form a initial position to a changed position it causes a change from a delayed valve actuator operation mode to a advanced valve actuator operation mode for said plurality of valve actuators which be surrounded by said plurality of eccentric valve actuator sleeves.
3. Apparatus as in claim 1 wherein a rotatory movement of a plurality of said eccentric valve actuator sleeves form a initial position to a changed position it causes a change from a advanced valve actuator operation mode to a delayed valve actuator operation mode for said plurality of valve actuators which be surrounded by said plurality of eccentric valve actuator sleeves.
4. Apparatus as in claim 1 wherein at least a linkage unit connect at least a actuator device with a plurality of said eccentric valve actuator sleeves for simultaneous actuation of said plurality of eccentric valve actuator sleeves.
Type: Application
Filed: Jan 20, 2012
Publication Date: Jul 25, 2013
Inventor: Alberto Keel (Grabs)
Application Number: 13/354,331
International Classification: F01L 1/34 (20060101);