Method for reducing particulates emissions from a diesel engine

This invention provides a method for operating a diesel engine with reduced emission of particulates as well as HC, CO, NOx, and SOx, comprising a corona discharge device for producing ozone in the air intake system, the corona discharge device comprising at least one first electrode (12), at least one second electrode (13) positioned a distance from the first electrode and a dielectric material (11) positioned between the first electrode and the second electrode; and a high frequency power supply (44) having an operational frequency of at least about 1,000 Hz adapted to provide electrical power to the corona discharge device. These harmful emissions from diesel engine are reduced, partly or completely, due to the complete combustion of fuel by supplying enough amount of ozone into the combustion chamber of engine. The particular advantageous feature of this invention is that it can be installed easily and inexpensively to existing and new engines without modifying the operating condition or the structure of engine itself.