A filter device for filtering automobile exhaust gas, the filter device comprising:
- a case including an inlet port through which exhaust gas combusted in an engine flows into a porous pipe and an exhaust port through which the exhaust gas is discharged after passing through the porous pipe and a filter member, the filter member including a metallic foam filter of a laminated type or rolled-up type through which the exhaust gas flown into the porous pipe passes;
- a front support flange mounted inside the case, the front support flange being fixed vertically to a front end portion of the filter member wrapping around the porous pipe, thereby holding the porous pipe in place and preventing the filter member from being pushed towards the front end;
- a rear support flange mounted inside the case, the rear support flange being fixedly fastened vertically to a rear end portion of the filter member wrapping around the porous pipe, thereby holding the porous pipe in place and preventing the filter member from being pushed towards the rear end wherein the filter member is mounted between the front support flange and the rear support flange;
- a metallic mat or a jacket wrapping around the metallic foam filter, the metallic foam filter being formed in the form of a network to preserve the original shape of the metallic foam filter and to provide durability thereto,
- a metallic fastener guide wrapping around the metallic foam filter to provide easy fastening of the filter member when the metallic foam filter is rolled up;
- and
- a metallic fastener device holding the metallic fastener guide to minimize deformation of the metallic foam filter and to reduce loss of the metallic foam filter,
- wherein the porous pipe mounted inside the filter member is formed with a plurality of holes such that the exhaust gas smoothly flows into the filter member and is discharged through the plurality of holes, the porous pipe being structured such that the width thereof decreases gradually towards a rear end portion of the porous pipe or increases gradually towards a rear end portion of the porous pipe, or such that the plurality of holes in the rear end portion of the porous pipe are smaller to cause a uniform flow rate even when the flow rate in the rear end portion of the porous pipe becomes high by high pressure due to a smaller flow area, or such that a conical member is inserted in the inside space of the porous pipe where the plurality of holes are formed, thereby enabling to uniformly collect particulate matters inside the pipe, or such that a pyramidal member is inserted in the inside space of the porous pipe where the plurality of holes are formed, thereby enabling to uniformly collect the particulate matters inside the pipe, so that a gradient in the flow rate inside the porous pipe does not occur,
- wherein the front support flange is not formed with a vent hole, and the rear support flange is formed with a plurality of vent holes through which the exhaust gas passing through the filter member is discharged.