Patent ID: 7469576

Claim:
A method for determining Top Dead Center rotational location of a piston in a cylinder of a multiple-cylinder internal combustion engine having a pressure sensor in the cylinder and having a crankshaft rotational position sensor, comprising the steps of: a) determining the rotational Location of Peak Pressure in said cylinder with respect to the indicated rotational location of said crankshaft position sensor by a procedure selected from the group consisting of determining Continuity of Polytropic Coefficient and determining Waveform Symmetry extrapolated to a peak, wherein said determining of Location of Peak Pressure by determining Continuity of Polytropic Coefficient includes the algorithm P before dV before = P after dV after , and wherein said determining of Location of Peak Pressure by determining Waveform Symmetry extrapolated to a peak includes the extrapolation algorithm LPP = Y 340 - ( X 340 X 340 - X 350 ) ⁢ ( Y 340 - Y 350 ) 1 - ( Y 340 - Y 350 ) ( X 340 - X 350 ) = Y intercept ( 1 - Slope ) ; and b) adding a calculated Heat Loss Offset to said determined Location of Peak Pressure to provide said Top Dead Center rotational location of said piston in said cylinder.