Patent ID: 7418336
Filing Date: 2008-08-26
Classification: F02B,F02D,F02M,Y02T

Abstract:
1. Method to operate an internal combustion engine, said engine comprising a multi-cylinder direct-injection engine operative lean of stoichiometry; each cylinder including a variable volume combustion chamber defined by a piston reciprocating therein between top-dead-center and bottom-dead-center points and a cylinder head; the piston reciprocating in repetitive cycles each cycle comprising intake, compression, expansion, and exhaust strokes, the method comprising: adapting a plurality of pressure sensing devices to monitor in-cylinder pressure during ongoing engine operation; monitoring in-cylinder pressure and a corresponding engine crank position to periodically to determine instantaneous in-cylinder pressure states corresponding to the engine crank position during the compression and expansion strokes; determining a plurality of pressure ratios based upon the instantaneous in-cylinder pressure states; and, determining a combustion heat release based upon the plurality of pressure ratios.