Abstract: A meshed plate-like heater is disposed between multi-layer cylindrical filters without contacting with the filters to constitute a DPF. The heater has a form in which strip-like electric conduction paths are arranged and developed side by side horizontally, and then made cylindrical such that the different electric resistances are set for the inlet portion, the outlet portion and the center portion so as to constitute a DPF for regenerating particulates. The regenerative heater realizes a uniform temperature distribution all over the regenerative heater within a range of from about 600.degree. C. which is the self-burning temperature of the particulates to 1,000.degree. C. which is the heat-resistance temperature of the filters, in 10 minutes after the start of regeneration.

Abstract: Thin plate-like electric heaters are disposed among multi-layer cylindrical filters for capturing particulates in positions without contacting with the filters. As the means for more reducing the power supply to the heater as the position of the heater is closer to the central cylinder of the multi-layer filters, the thicknesses of the thin plate-like electric heaters or the geometrical patterns of the electric conduction paths are changed to thereby set the resistance values of the heaters in advance in order to reduce the temperature of the central-side cylinder which is apt to be high to thereby realize the balance with the temperature of the outer-circumferential cylinder, or the electric conduction quantity to the heaters is selectively more reduced as the position of the heater is closer to the central cylinder to realize the balance of temperature distribution with the filter on the outer-circumferential side filter.

Abstract: An exhaust gas purifier which can regenerate its trapper for trapping particulate matter (PM) in exhaust over the entire area of its filter portion, even if a large amount of PM is trapped. PM trapped on the trapper is burned by heating the trapper with an electric heater inserted in the trapper on its downstream side. With this arrangement, PM is less likely to accumulate between the electric heater and the trapper. Also, PM is less likely to adhere to the surface of heater supporting insulators. Thus, it is possible to prevent short-circuiting between the heater and the trapper through PM.