Internal combustion engine comprising a variable valve lift system and a variable valve timing system, and a method for such an engine

Abstract

An internal combustion engine having a variable valve lift system whereby the engine can operate selectively in either of at least two valve lift modes, and a variable valve timing (VVT) system, as well as a method for controlling valve timing in such an engine are presented. The method comprises providing, in response to a valve lift mode shift, a control pulsing signal for the VVT actuator in order to compensate for the effects of the valve lift on the VVT system.

1 . A method for controlling valve timing in an internal combustion engine capable of operating selectively in either of at least two valve lift modes, the engine having a variable valve timing (VVT) system, the method comprising: 
 sending a control pulsing signal to a VVT system actuator in response to a valve lift mode shift.    
   
   
       2 . The method according to  claim 1 , wherein said control pulsing signal is sent to compensate for oil pressure variation caused by said valve lift mode shift.  
   
   
       3 . The method according to  claim 2  wherein said control pulsing signal is such that a VVT position remains essentially the same before, during and after said valve lift mode shift.  
   
   
       4 . The method according to  claim 3 , wherein said control pulsing signal is sent after a predetermined time interval following a signal for said valve lift mode shift.  
   
   
       5 . The method according to  claim 4 , wherein said control pulsing signal is terminated by a decrement function.  
   
   
       6 . An automotive system, comprising: 
 an internal combustion engine having a variable valve lift system whereby said engine can operate selectively in either of at least two valve lift modes,    said engine further having a variable valve timing (VVT) system comprising a VVT actuator, and    a control unit adapted to provide, in response to a valve lift mode shift, a control pulsing signal for said VVT actuator.    
   
   
       7 . An automotive system according to  claim 6 , wherein said control pulsing signal is sent after a predetermined time interval following a signal for said valve lift mode shift.  
   
   
       8 . An automotive system according to  claim 7 , wherein said controller provides said control pulsing signal is terminated by a decrement function.  
   
   
       9 . An automotive system according to  claim 8 , wherein said controller provides said control pulsing signal to compensate for oil pressure variation caused by said valve lift mode shift.  
   
   
       10 . An automotive system according to  claim 9 , wherein said controller provides said control pulsing signal is such that a VVT position remains essentially the same before, during and after said valve lift mode shift.