Apparatus and method for filtering particulate and NOx emissions

A particulate trap system for an internal combustion engine, comprising:

• a particulate trap module positioned to accept engine exhaust gas including a plurality of passages having porous walls for receiving the exhaust gas, wherein the porous walls filter particulates from the exhaust gas;
• a reversing apparatus, said reversing apparatus periodically reversing a portion of the filtered exhaust gas back through the porous walls in reverse flow at a pressure drop, resultant flow velocity, and duration sufficient to dislodge build-up of particulates from the porous walls;
• and
• wherein said reverse flow is entirely within the same exhaust channel through which exhaust is filtered.

A self-cleaning particulate filter module for a multi-cylinder internal combustion engine exhaust comprising:

• a particulate filter, said filter being disposed in a single exhaust channel, said channel being common to all cylinders, said particulate filter filtering particulates from the exhaust when said exhaust flows in a first direction;
• a flow reverser, said flow reverser being disposed within said single exhaust channel to clean particulate build up from said filter by reversing an exhaust flow through said filter in a second direction;
• and
• wherein said second flow direction is entirely within said single exhaust channel.

A self-cleaning particulate filter module for a multi-cylinder internal combustion engine exhaust comprising:

• a particulate filter, said filter being disposed in a single exhaust channel, said channel being common to all cylinders, said particulate filter filtering particulates from the exhaust when said exhaust flows in a first direction;
• a flow reverser, said flow reverser being disposed within said single exhaust channel to clean particulate build up from said filter by reversing an exhaust flow through said filter in a second direction;
• and
• wherein said reversed exhaust flow is filtered exhaust.

An exhaust particulate filter system for an internal combustion engine, comprising:

• a particulate trap;
• the particulate trap including a plurality of passages disposed to receive engine exhaust gas;
• an exit chamber for receiving filtered exhaust gas passing through the particulate trap;
• a separation chamber operatively connected to the particulate trap for receiving a reverse flow from a portion of the particulate trap;
• a flow restriction apparatus, said flow restriction apparatus being disposed to selectively create a pressure difference between the exit chamber and the separation chamber in response to a pre-established operating condition, such that the pressure in the exit chamber is greater than the pressure in the separation chamber, thereby forcing a portion of the filtered exhaust gas from the exit chamber back through a selected portion of the particulate trap in reverse flow and at sufficient pressure drop, resultant flow velocity, and duration to dislodge build-up of particulates from the particulate trap;
• and
• a flow directing device oriented to receive the reverse flow from the selected portion of the particulate trap and direct the reverse flow to the separation chamber.

A method of regenerating a wall-flow particulate trap having a plurality of contiguous porous walls for filtering particulate from an exhaust system of an internal combustion engine, the method including the steps of:

• creating a backpressure in the entire exhaust system from a location downstream of the trap;
• creating a reverse pressure drop across only a portion of the porous walls to dislodge accumulated particulate therefrom;
• and
• causing a portion of filtered exhaust gas to flow back through said portion of the porous walls to carry the dislodged particulate out of the trap.