Mixer for Aftertreatment of Exhaust Gases

A mixer for a device for selective catalytic reduction of exhaust gases from internal combustion engines, for uniform distribution of a reducing agent in the exhaust gas stream that is introduced into said exhaust gas stream at the catalyst inlet, wherein said mixer comprises:

• a structure of mixer elements through which the mixture of exhaust gas and reducing agent is configured to flow, wherein;
• said mixer elements are adapted for direct electrical heating with an electric current flowing through them due to their electrical resistance.

A mixer according to claim 1, wherein said mixer elements have the shape of turbine blades.

A mixer according to claim 1, wherein said structure of mixer elements is arranged substantially ring-shaped.

A mixer according to claim 1, wherein individual mixer elements are electrically interconnected in series so as to form a heating circuit.

A mixer according to claim 1, wherein said mixer elements comprise a heating element alloy.

A mixer according to claim 1, wherein an electrical contact to said mixer to a power supply is effected via a pin which is insulated by a sleeve is connected to a housing of said mixer.

A mixer according to claim 1, wherein a power supply to said mixer is effected in a radial direction relative to said exhaust gas stream.

A mixer according to claim 1, wherein a power supply to said mixer is effected in an axial or a coaxial direction relative to said exhaust gas stream.

A mixer according to claim 1, wherein a connection to ground is effected via a pin which is insulated by a sleeve is connected to a housing of said mixer.

A mixer according to claim 1, wherein a connection to ground is effected via a pipe section contacting ground of a housing of said mixer.

A mixer according to claim 1, wherein said mixer elements are produced from a sheet metal strip by punching and bending, and wherein said sheet metal strip comprising said mixer elements is bent to a ring shape.

A mixer according to claim 1, wherein said mixer elements are provided with tabs that are received between insulation plates that are held between pipe section flanges of pipe sections of a housing of said mixer.

A mixer according to claim 1, wherein said mixer elements are provided with creases that enhance mechanical rigidity.

A mixer according to claim 1, wherein the electrical resistance of individual mixer elements varies.

A mixer for a device for selective catalytic reduction of exhaust gases from internal combustion engines, for uniform distribution of a reducing agent in the exhaust gas stream that is introduced into said exhaust gas stream at the catalyst inlet, wherein said mixer comprises:

• a structure of mixer elements through which the mixture of exhaust gas and reducing agent is configured to flow, wherein said mixer elements are adapted for direct electrical heating with an electric current flowing through them due to their electrical resistance, wherein said mixer elements are produced from a sheet metal strip by punching and bending, and wherein said sheet metal strip comprising said mixer elements is bent to a ring shape.

A mixer according to claim 33, wherein said mixer elements have the shape of turbine blades.

A device for selective catalytic reduction of exhaust gases in an internal combustion engine, the engine having 1) an exhaust gas pipe leading to a mixer, 2) a reducing agent pipe leading to a reservoir for reducing agent and, in a flow direction, opening into said exhaust gas pipe upstream of said mixer, and 3) a catalyst in a flow direction downstream of said mixer, wherein said mixer comprises:

• a structure of mixer elements through which the mixture of exhaust gas and reducing agent is configured to flow, which said mixer elements are adapted for direct electrical heating with an electric current flowing through them due to their electrical resistance.