Patent ID: 9540970
Date: 2017-01-10
CPC Classifications: F01L

Claim:
1. A method for operating an internal combustion engine with a lift-variable gas-exchange valve train comprising an actuator and a camshaft with a carrier shaft and a cam part that is rotationally locked on the carrier shaft and is movable between three axial cam positions and has a group of three adjacent cams of different lifts and a groove-shaped connecting link path with a first path section and a second path section that lift in both axial directions of the cam part and are arranged completely one behind the other over a circumference of the cam part, the actuator being actuatable to selectively extend first and second actuator pins that are couplable into the connecting link path, in order to move the cam piece to one of the axial positions, and the cam part is reset into an outer target axial position during operation of the internal combustion engine, the first actuator pin in a base position phase is extended and retracted and the second actuator pin in a following second base position phase is extended and retracted, wherein the actuator is controlled as follows: a) extending the first actuator pin at a circumferential path position that lies in front of the first path section and behind the second path section, b) holding the first actuator pin in an extended position within a circumferential path angle that encloses the two path sections at least once, c) retracting the first actuator pin from a circumferential path position that lies behind the second path section and in front of the first path section, d) extending the second actuator pin at a circumferential path position that lies in front of the first path section and behind the second path section, e) holding the second actuator pin in the extended position within a circumferential path angle that encloses the two path sections at least once, f) retracting the second actuator pin from a circumferential path position that lies behind the second path section and in front of the first path section, wherein the axial lift of the second path section shifts the cam part in the axial direction and wherein the second actuator pin is adjacent to the first actuator pin in the axial direction of the cam part base position.