 The engine featured an aluminium block, DOHC chain driven valvetrain, common rail direct injection and variable geometry turbocharger.In Spring 2005, Mercedes-Benz unveiled their first application of a mass-produced aluminum block diesel engine for passenger vehicles and commercial use.While aluminum is traditionally considered of inferior strength and temperature resistance to withstand diesel applications, Mercedes engineers made extensive use of CAD/CAM design to arrive at an aluminum block that would meet with Mercedes' testing and reliability standards.