Method to improve combustion stability in a controlled auto-ignition combustion engine

Method to control timing of combustion in an internal combustion engine operative in a controlled auto-ignition combustion mode, said engine comprising a direct-injection, four-stroke, internal combustion engine including a variable volume combustion chamber defined by a piston reciprocating within a cylinder between top-dead-center and bottom-dead-center points and a cylinder head comprising an intake valve and an exhaust valve;

• the method comprising:
• determining a state of an engine operating parameter corresponding to combustion heat release subsequent to operating the internal combustion engine in the controlled auto-ignition combustion mode for an extended period of time;
• determining a preferred heat transfer rate from the combustion chamber corresponding to the state of the engine operating parameter corresponding to the combustion heat release subsequent to operating the internal combustion engine in the controlled auto-ignition combustion mode for an extended period of time;
• and
• applying a surface coating to a portion of surfaces of the combustion chamber to effect the preferred heat transfer rate from the combustion chamber.