Eight-stroke engine cycle

A method of operating an engine in an eight-stroke mode comprising:

• a first stroke forming an intake stroke and including opening an intake valve via a first peak of a first cam lobe to provide communication between an air source and a combustion chamber formed by an engine structure defining a cylinder bore and a piston disposed within the cylinder bore, the first stroke further including providing a first fuel mass to the combustion chamber;
• a second stroke immediately subsequent to the first stroke and forming a first compression stroke;
• a third stroke immediately subsequent to the second stroke and forming a first expansion stroke, the first expansion stroke including a first power stroke where the air-fuel mixture provided in the first stroke is ignited;
• a fourth stroke immediately subsequent to the third stroke and forming a second compression stroke, the fourth stroke including an exhaust valve in communication with the combustion chamber being in a closed position and preventing discharge of gas from within the combustion chamber when a valve lift mechanism engaged with the exhaust valve is engaged by a second peak of a second cam lobe and including providing a second fuel mass to the combustion chamber;
• a fifth stroke immediately subsequent to the fourth stroke and forming a second expansion stroke including the intake valve being in the closed position when a valve lift mechanism engaged with the intake valve is engaged by the first peak of the first cam lobe, the second expansion stroke including a second power stroke where the second fuel mass is ignited;
• a sixth stroke immediately subsequent to the fifth stroke and forming a third compression stroke, the third compression stroke including the exhaust valve being in the closed position;
• a seventh stroke immediately subsequent to the sixth stroke and forming a third expansion stroke, the third expansion stroke including the intake valve being in the closed position;
• and
• an eighth stroke immediately subsequent to the seventh stroke, the eighth stroke forming an exhaust stroke and including opening the exhaust valve via the second peak of the second cam lobe.

A method of operating an engine in an eight-stroke mode comprising:

• a first stroke forming an intake stroke and including opening an intake valve via a first peak of a first cam lobe to provide communication between an air source and a combustion chamber formed by an engine structure defining a cylinder bore and a piston disposed within the cylinder bore, the first stroke further including providing a first fuel mass to the combustion chamber;
• a second stroke immediately subsequent to the first stroke and forming a first compression stroke;
• a third stroke immediately subsequent to the second stroke and forming a first expansion stroke, the first expansion stroke including a first power stroke where the air-fuel mixture provided in the first stroke is ignited;
• a fourth stroke immediately subsequent to the third stroke and forming a second compression stroke, the fourth stroke including an exhaust valve in communication with the combustion chamber being in a closed position and preventing discharge of gas from within the combustion chamber when a valve lift mechanism engaged with the exhaust valve is engaged by a second peak of a second cam lobe;
• a fifth stroke immediately subsequent to the fourth stroke and forming a second expansion stroke including the intake valve being in the closed position when a valve lift mechanism engaged with the intake valve is engaged by the first peak of the first cam lobe;
• a sixth stroke immediately subsequent to the fifth stroke and forming a third compression stroke, the third compression stroke including the exhaust valve being in the closed position and providing a second fuel mass to the combustion chamber;
• a seventh stroke immediately subsequent to the sixth stroke and forming a third expansion stroke, the third expansion stroke including a second power stroke where the second fuel mass is ignited;
• and
• an eighth stroke immediately subsequent to the seventh stroke, the eighth stroke forming an exhaust stroke and including opening the exhaust valve via the second peak of the second cam lobe.