Abstract: An internal combustion engine includes a turbocharger and a selectively operable positive displacement supercharger downstream of the turbocharger in the intake path. An input shaft of the supercharger is mechanically coupled to and driven by a piston-driven crankshaft. A bypass valve is configured to selectively bypass at least a portion of the air from the turbocharger air outlet around the supercharger. Power and fuel consumption are optimized by operating the supercharger to dilute the fuel-air mixture to achieve an excess air factor ? above 1.0, and in some cases above the upper range (?=1.3) of normal stoichiometric operation. The engine can operate in a lean low temperature combustion mode (e.g., HCCI) with the supercharger operating, and in a stoichiometric spark ignition combustion mode with the supercharger bypassed.

Abstract: A control system and method to dynamically determine a parametric value for combustion chamber deposits (CCD), e.g. in a controlled auto-ignition engine, including in-situ evaluation of thickness of CCD, based on a sensor which monitors combustion. It includes a temperature sensor operative to monitor the combustion chamber, and a CCD parameter that is based upon a peak combustion temperature measured at a crank angle. A CCD parameter can also be determined utilizing an in-cylinder pressure monitor, wherein a combustion chamber deposit parameter is based upon crank angle location of a peak in-cylinder pressure parameter.

Abstract: A method is disclosed for expanding the mid load range of a four-stroke gasoline direct-injection controlled auto-ignition combustion engine. The engine includes at least one cylinder containing a piston reciprocably connected with a crank and defining a variable volume combustion chamber including an intake valve controlling communication with an air intake and an exhaust valve controlling communication with an exhaust outlet. A system is employed for variably actuating the intake and exhaust valves. The valve actuating system is employable to operate the intake and exhaust valves with an exhaust re-compression or an exhaust re-breathing valve strategy. A reservoir chamber in communication with the combustion chamber is provided for temporary holding of residual burned gas. Residual burned gas in the combustion chamber and the exhaust outlet enters into the reservoir chamber and then loses thermal energy while in the reservoir chamber before being drawn back into the combustion chamber.