Method and device for operating an internal combustion engine in the event of a fault in a crankshaft sensor

Abstract

A method for operating an internal combustion engine in the event of a fault in a crankshaft sensor is provided, the internal combustion engine having at least two camshafts and a speed and/or a position of the internal combustion engine being derived from a signal taken from the camshaft. In order to improve the exhaust gas performance of the internal combustion engine even in a crankshaft emergency operating mode, only a first camshaft is used to determine the speed and/or the position of the internal combustion engine, while the second camshaft. is adjusted in its angle of rotation in order to set a variable valve operating mechanism on the intake and exhaust valves of the internal combustion engine that are driven by the second camshaft.

1 - 10 . (canceled) 
     
     
         11 . A method for operating an internal combustion engine having at least two camshafts in the event of a fault in a crankshaft sensor, comprising:
 determining at least one of a speed and a position of the internal combustion engine based on a signal from only a first camshaft; and   adjusting an angle of rotation of a second camshaft in order to set a variable valve operating mechanism on intake valves and exhaust valves of the internal combustion engine which are driven by the second camshaft.   
     
     
         12 . The method as recited in  claim 11 , wherein the first camshaft assumes a reference position with respect to a crankshaft driven by the internal combustion engine and rotates in a specified transmission ratio with respect to the crankshaft, the rotary motion of the first camshaft being detected by a camshaft sensor. 
     
     
         13 . The method as recited in  claim 12 , wherein the first camshaft which is in the reference position with respect to the crankshaft at least one of selectively opens and closes the exhaust valves of the internal combustion engine, and wherein the second camshaft which has been adjusted at least one of selectively opens and closes the intake valves of the internal combustion engine. 
     
     
         14 . The method as recited in  claim 12 , wherein at least three camshafts are provided, and wherein the respective angles of rotation of the second and third camshafts are adjusted. 
     
     
         15 . The method as recited in  claim 14 , wherein the respective angles of rotation of the second and third camshafts are adjusted as a function of at least one of the speed of rotation of the internal combustion engine and the position of the internal combustion engine detected by the camshaft sensor. 
     
     
         16 . The method as recited in  claim 15 , wherein, in the adjustment of the respective angles of rotation, the second and third camshaft driven by the crankshaft are each shifted from a specified position with respect to the crankshaft so as to change the control times of at least one of the intake and exhaust valves of the internal combustion engine. 
     
     
         17 . The method as recited in  claim 13 , wherein the adjustment of the second camshaft occurs between two permanently defined angles of rotation within an adjustment range of the second camshaft. 
     
     
         18 . The method as recited in  claim 17 , wherein the adjustment of the second camshaft occurs in a step-less manner within the adjustment range of the camshaft. 
     
     
         19 . A control device for operating an internal combustion engine having at least two camshafts in the event of a fault in a crankshaft sensor, comprising:
 means for determining at least one of a speed and a position of the internal combustion engine based on a signal from only a first camshaft; and   means for adjusting an angle of rotation of a second camshaft in order to set a variable valve operating mechanism on intake valves and exhaust valves of the internal combustion engine which are driven by the second camshaft.   
     
     
         20 . The device as recited in  claim 19 , wherein:
 a control unit controls respective rotary motions of the first and second camshafts;   the control unit sets the first camshaft in a reference position with respect to the crankshaft;   the control unit is connected to a camshaft sensor which detects the rotary motion of the first camshaft;   the control unit determines the at least one of a speed and a position of the internal combustion engine based on an output signal of the camshaft sensor; and   the control unit controls, as a function of the determined speed of the internal combustion engine, an adjusting device connected to the second camshaft for adjusting the angle of rotation of the second camshaft from an original position.