A method for improving the operation of an HCCI engine

摘要

A method for operation of a homogeneous charge compression ignition (HCCI) engine having a plurality of cylinders, and at least one exhaust and one intake valve per cylinder. Comprising, for each cylinder, the following sequence of steps in each combustion cycle: introducing a quantity of fuel; performing a compression in the cylinder leading to an increase in cylinder pressure to obtain a primary ignition; performing an expansion in the cylinder leading to a decrease of the cylinder pressure; opening and closing the exhaust valve 20; performing a second compression in the cylinder and, at the same time, introducing a predetermined second quantity of fuel leading to an increase in cylinder pressure to obtain an auxiliary ignition; performing a second expansion in the cylinder leading to a decrease of the cylinder pressure; and opening and closing the intake valve 30. During periods of partial load the engine will behave like a two stroke, rather than a four stroke and have better fuel economy and lower NOX emissions.