Abstract: A catalyzer for a Diesel engine , where the catalyzer is located inside the combustion chamber, the pre-combustion chamber, the injector or the pre-heater. In one embodiment, the interior of the pre-combustion or combustion chamber is coated with a ceramic layer and submerged in an aluminum hydroxide and zirconium suspension. A coating of catalytic metals, such as rhodium, platinum, palladium, copper, silver aluminum, manganese and zinc, is then applied to the ceramic base inside the chamber. In another embodiment, the coating is applied by replacing the ceramic base by a bath of catalytic metals.