NEGATIVE PRESSURE OPERATING METHOD

Method of operating an internal combustion engine that applies to both types of ignition types; Spark Ignition (SI) and Compression Ignition (CI). The method comprises opening the intake valve, allowing the fuel and air mixture to flow through the intake valve and into the chamber during at least during a portion of the intake stroke; closing the intake port during a portion of the intake stroke; applying a negative pressure during a portion of the intake stroke; directly or indirectly igniting the fuel and air mixture during a portion of the intake stroke; opening the exhaust valve during the exhaust stroke. The operation of intake valve, the exhaust valve, and the application of the ignition source is performed at any time during the intake and/or exhaust stroke or cycle.