Abstract: A method of casting an article using a mold including a mold cavity, the method including the steps of providing a compound containing a halogen at at least a portion of a surface of the mold adjacent the mold cavity, pouring molten metal into the mold cavity and allowing the metal to cool and solidify, and removing the article from the mold.

Abstract: An internal combustion engine comprising, an engine management unit, a combustion chamber having an inlet port and an outlet port, a fuel supply mechanism to supply gasoline to the engine, a valve train mechanism to permit introduction of air to the inlet port of the combustion chamber and release exhaust gases from the outlet port of the combustion chamber, and an external recirculating system whereby exhaust gases from the outlet port may be passed to the inlet port, wherein, the engine management unit is operable to, control the valve train mechanism to retain and/or rebreathe exhaust gases within the combustion chamber to cause the engine to operate in a controlled auto ignition combustion mode, and control the external recycling system to supply exhaust gases to the inlet port in the controlled auto ignition combustion mode, such that self-ignition occurs in the combustion chamber.