Abstract: A method is disclosed for expanding the mid load operation limit in a four-stroke gasoline direct-injection controlled auto-ignition combustion engine. A system is employed for variably actuating the intake and exhaust valves and for operating the valves with an exhaust re-compression or exhaust re-breathing valve strategy. A spark plug is provided. A fuel injector having multiple injection capability is employed. A first fuel charge is injected into the combustion chamber to form a lean air-fuel mixture. A second fuel charge is injected into the combustion chamber to form a stratified air-fuel mixture having an ignitable mixture located near the spark plug.

Abstract: A method is disclosed for controlling the air-fuel ratio in a four-stroke gasoline direct-injection controlled auto-ignition combustion. The engine is operated with two sequential pairs of expansion and contraction strokes during two revolutions of the engine crank, the two revolutions defining a combustion cycle. A system is employed for variably actuating the intake and exhaust valves and adjusting the flow of air and burned gases entering the combustion chamber. Adjusting the flow affects the resulting air-fuel ratio in the combustion chamber. 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. Either valve strategy affects the air-fuel ratio in the cylinder and causes a proportion of burned gases from previous combustion cycles to be retained in the cylinder to provide the necessary conditions for auto-ignition of the air-fuel mixture.

Abstract: A method of operating a four-stroke gasoline direct-injection controlled auto-ignition combustion engine includes opening both the intake and exhaust valves during terminal portions of the expansion strokes and initial portions of the contraction strokes, injecting fuel directly into the combustion chamber for mixing with retained gases and igniting the fuel near the ends of the contraction strokes. In the process, combustion gases are expanded to produce power during major portions of the expansion strokes, combusted gases are blown down into the exhaust outlet and the air inlet and are partially redrawn into the cylinder with fresh air during the terminal portions of the expansion strokes so the air charges are heated by the hot exhaust gases. Portions of the charges re-expelled and the remaining portions of the charges and injected fuel are compressed for ignition of the dilute fuel/air and exhaust gas mixture. Substantial reductions of NOx emissions result from the method.

Abstract: Low load operating point for a direct-injection controlled auto-ignition four-stroke internal combustion engine is reduced without compromising combustion stability through a split-injection control operative to introduce a first fuel fraction, air and exhaust gases into the combustion chamber during an intake event and a second fuel fraction into the combustion chamber during a compression event.

Abstract: A combustion chamber for an internal combustion engine includes a closed end cylinder having an axis. A piston is reciprocable in the cylinder and includes a generally flat rim having an inner edge surrounding a recessed bowl into which the fuel is primarily injected, the bowl having a floor and a surrounding side formed by an arcuate surface connecting tangentially with the floor and extending to the rim inner edge. A spark plug has a centerline through the spark gap and is offset to one side of the cylinder axis with the spark gap extending into the combustion chamber toward the axis. A fuel injector is offset to an opposite side of the axis with the spray tip aimed to direct a generally conical fuel spray into the piston bowl with a portion of the fuel spray passing near the spark gap. Various dimensional characteristics are disclosed.

Abstract: Low load operating point for a direct-injection controlled auto-ignition four-stroke internal combustion engine is reduced without compromising combustion stability through a split-injection control operative to introduce a first fuel fraction, air and exhaust gases into the combustion chamber during an intake event and a second fuel fraction into the combustion chamber during a compression event.

Abstract: Low load operating point for a controlled auto-ignition four-stroke internal combustion engine is reduced without compromising combustion stability through a valve control operative to establish sub-atmospheric pressure conditions within the combustion chamber into which fuel and exhaust gases are introduced.

Abstract: The present invention provides a fuel injector mounted on a side of a combustion chamber and delivers an ovalized fuel spray toward an oblong piston bowl of the chamber. The ovality of the spray is selected in relation to the oblong piston bowl and the motion of the combustion chamber air charge during the piston compression stroke to maintain the fuel charge within the piston bowl volume (including the space above the bowl) during compression and combustion of the fuel charge in the chamber. The shape of the oval spray may be adjusted as desired. In a specific embodiment, the ovality of the fuel spray indicated by the ratio of the major dimension to the minor dimension is in the range of about 2/1 to 4/1 for delivery into an oblong piston bowl with an ovality of about 1.2/1 to 1.5/1.

Abstract: An engine combustion chamber includes a cylinder head, a cylinder wall and a piston. The piston has a bowl volume formed therein. A fuel injector is disposed adjacent one edge of the bowl and an ignition source is within a predetermined distance of another, substantially opposite, edge of the bowl. The bowl has a transporting surface which directs a fuel-air charge from the bowl volume toward the ignition source. The piston, bowl and cylinder head cooperate through a plurality of design features to provide an efficient combustion chamber.