Method for varying valve timing of an internal combustion engine

Abstract

A technique is used for adjusting the valve timing of an internal combustion engine with a cam shaft and a cam lobe displaced at a rotational angle with respect to one another. Under interposition of a cam following element, such as, for example, a bucket tappet, the cam shaft and the cam lobe work together with intake or exhaust valves as well as the camshaft actuator present on the camshaft, through which the position and/or the attitude of rotation of the camshaft to the crankshaft can be changed. To decrease the valve opening time, the camshaft can be adjusted toward hate” during a valve stroke, while the camshaft is adjusted toward “early” during the immediately subsequent base circle phase of the affected camshaft. To increase the valve opening times the camshaft can be adjusted toward “early” during a valve stroke, while the camshaft is adjusted toward “late” during the immediately subsequent base circle phase of the affected camshaft. This technique permits adjustment of the angular attitude of the camshaft as well influence on the valve stroke curve.

1 - 3 . (canceled)  
   
   
       4 . A method for changing a valve timing of an internal combustion engine with a camshaft and a cam lobe displaced at a rotational angle with respect to each other, the camshaft and the cam lobe, under interposition of at least one appropriate cam following element, acting together with intake or exhaust valves of the internal combustion engine as well as with a camshaft actuator situated on the camshaft, through which at least one of a position and a rotational attitude of the camshaft can be adjusted for a crankshaft, comprising: 
 (a) adjusting the camshaft toward “late” during a valve stroke and toward “early” during an immediately subsequent base circle phase of the camshaft to decrease a valve opening time, and    (b) adjusting the camshaft toward “early” during a valve stroke and toward “late” during an immediately subsequent base circle phase of the camshaft to increase the valve opening time.    
   
   
       5 . The method as claimed in  claim 4 , wherein the internal combustion engine is a double-rowed, 6-cylinder engine with symmetrical ignition sequence for each cylinder bank.  
   
   
       6 . The method as claimed in  claim 4 , wherein the internal combustion engine is equipped with a device for valve stroke change-over.  
   
   
       7 . The method as claimed in  claim 4 , wherein the cam following element is a bucket tappet.  
   
   
       8 . The method as claimed in  claim 5 , wherein the internal combustion engine is equipped with a device for valve stroke change-over.  
   
   
       9 . The method as claimed in  claim 7 , wherein the internal combustion engine is a double-rowed, 6-cylinder engine with symmetrical ignition sequence for each cylinder bank.  
   
   
       10 . The method as claimed in  claim 7 , wherein the internal combustion engine is equipped with a device for valve stroke change-over.  
   
   
       11 . The method as claimed in  claim 9 , wherein the internal combustion engine is equipped with a device for valve stroke change-over.