NOx is formed as a by-product by diesel engines and generally increases with Exhaust Gas Temperature (EGT). Newer OEM engine designed have improved combustion efficiency to meet more stringent requirements for diesel particulate matter (DPM) emissions but often at the expense of increased Nix production. EnerBurn conditions diesel engine to improve fuel combustion efficiency by increasing the burn rate of diesel during the poser stroke of the piston. As a consequence in-cylinder combustion is more complete and EGT is reduced thereby lowering NOx production.