The specific power (kW/litre) that petrol internal-combustion engines produce has increased dramatically with the introduction of turbocharging and direct injection. This increase places extra strain on engine cooling because more heat needs to be removed from smaller metal components. This is especially true with piston crowns in downsized engines. Federal-Mogul has just released its new Elastothermic pistons for petrol engines that feature an internal oil gallery in the piston crown. This technology has been used on diesel engines for some time. An oil jet that sprays the underside of the piston and so cools it feeds the gallery. A cooler piston crown (by as much as 30 degrees Celsius) gives the combustion chamber better knock (auto-ignition) resistance and allows higher compression and boost pressures. This in turn has emission and performance benefits, which is critical in the engine-downsizing game.