Patent ID: 7000596

Claim:
A method of controlling combustion of a fuel within a combustion chamber of an internal combustion engine, said method comprising: (a) during a cycle of said internal combustion engine: (1) introducing an intake charge into said combustion chamber during an intake event of said cycle, said combustion chamber partially defined by a piston, (2) introducing a first quantity of said fuel into said combustion chamber during said intake event or a compression event of said cycle, wherein said first quantity of said fuel and said intake charge are compressed and premixed at or near completion of said compression event, (3) directly injecting a second quantity of said fuel into said combustion chamber when said piston is near top dead center, (4) burning said fuel in said combustion chamber during a power event of said cycle, (5) to a controller, delivering a pre-combustion sensor signal (P(A)) determined prior to combustion of said first quantity of said fuel and a first post-ignition sensor signal (P(B)) determined during combustion of said fuel, said sensor signals being indicative of a pressure within said combustion chamber, (b) calculating an estimated SOC of said first quantity of said fuel within said combustion chamber from said pre-combustion sensor signal and said first post-ignition sensor signal, (c) during a subsequent cycle of said engine, varying an ignition lever if said estimated SOC of said first quantity of said fuel is different than a predetermined target SOC of said first quantity of said fuel.