A method for removing particulates from internal combustion exhaust gases in a system which includes a first gas conduit which connects with an engine exhaust pipe and which communicates with a trapping chamber containing means for filtering or trapping particulate matter present in the exhaust gas. A second gas conduit connects with said first gas conduit at a location upstream of the said trapping chamber and leads to a regenerating chamber which contains an electrically conductive substrate which carries an oxidation catalyst. A third gas conduit carries the hot gas from the regenerating chamber and connects with said first gas conduit at a location also upstream of said trapping chamber. The electrically conductive substrate material within the regenerating chamber is part of an electrical circuit and is heated by current passing therethrough. Means are provided for injecting a combustible fuel into the regenerating chamber wherein the fuel-exhaust gas mixture is effectively heated and burned therein and the heated gas then passes into the trapping chamber to incinerate and burn off the particulate collected therein. Valve means are provided to selectively direct exhaust gas flow through to the trapping chamber and the regenerating chamber.

An exhaust particulate cleaning device for a diesel engine comprising a trap case which is located in a passageway of the exhaust gas and which has therein a filter material for trapping the exhaust particulates contained in the exhaust gas, an electric heater for igniting and burning the exhaust particulates trapped in the filter material, a larger bypass passage of the exhaust gas bypassing the trap case, and a control valve in the bypass passage for opening and closing the bypass passage.

A method and apparatus for regenerating a catalyzed particulate filter in the exhaust stream of a combustion source (particularly a diesel engine) are provided that do not necessitate excessive heating of the exhaust stream flowing from the combustion source. During regeneration the intake air is supplied in a pulsed manner, preferably but not necessarily, to less than all of the cylinders of the engine so that the combined engine exhaust carries sufficient "fuel", primarily in the form of a carbon monoxide and a hydrocarbon fraction, that will be catalytically oxidized thereby generating an exotherm. Due to the liberation of heat during that carbon monoxide and hydrocarbon oxidation above the light-off temperature of the filter, the particulates stored by the filter will be ignited and burned cleaning and regenerating the filter.

An HC (hydrocarbon) supplementing device is mounted in an exhaust purification device of an internal combustion engine, wherein the amount of HC in the fuel to be added is automatically adjusted to a degree corresponding to the operating conditions of the engine. Accordingly, the supply of just enough HC becomes possible without the use of a complex mechanism for adjusting the supply of HC, and the exhaust gas can be sufficiently purified without wasting fuel.

A diesel engine exhaust particulate trap and regeneration system for trapping of particulates in the engine exhaust gases and periodic burning thereof. Collected particulates in the trap are burned utilizing a burner means immediately upstream of the trap. An air and fuel supply system are associated with the burner which controls the combustion temperature within the burner in order to completely and efficiently burn the particulates.