Claims:We claim:
1. A mixer (12) for an exhaust gas path, said mixer (12) comprising:
an actuator (14) adapted to be controlled by an engine control unit (16);
a control rod (18) coupled to said actuator (14), said control rod (18) adapted to translate when actuated by said actuator (14); and
at least one vane (20) coupled to said control rod (18), said at least one vane (20) rotatable to vary an angle of attack when exhaust gas impinges on said at least one vane (20), wherein the angle of attack is dependent on an engine operating condition.

2. The mixer (12) for the exhaust gas path in accordance with Claim 1, wherein the engine operating condition is dependent on at least one of an injection quantity, rail pressure, accelerator pedal position, engine speed, number of fuel injections per unit time, engine operating temperature, and engine coolant temperature.

3. The mixer (12) for the exhaust gas path in accordance with Claim 1, wherein the operation of the mixer (12) is dependent on a mass flow rate of exhaust gas flow through said mixer (12).

4. The mixer (12) for the exhaust gas path in accordance with Claim 3, wherein the at least one vane (20) is adapted to rotate to increase an angle of attack when the mass flow rate of exhaust gas increases thereby facilitating impinging the exhaust gas closer to an entry of a catalytic converter that is positioned downstream from said mixer (12) such that the exhaust gas flows through a larger distance in said catalytic converter.

5. The mixer (12) for the exhaust gas path in accordance with Claim 3, wherein the at least one vane (20) is adapted to rotate to decrease an angle of attack when the mass flow rate of exhaust gas decreases thereby facilitating impinging the exhaust gas farther away from an entry of a catalytic converter that is positioned downstream from said mixer (12) such that the exhaust gas flows through a shorter distance in said catalytic converter.

6. The mixer (12) for the exhaust gas path in accordance with Claim 1, wherein the operation of the mixer (12) is dependent on a quantity of reducing agent injected into the exhaust gas path upstream from said mixer (12). , Description:Field of the invention:
[0001] This disclosure relates to a mixer for dispersing exhaust gas containing a reducing agent to a catalytic converter of an internal combustion engine.
Background of the invention:
[0002] U.S. Patent Application Number US2007/0256413A1 describes a variable geometry EGR mixer and system. An internal combustion engine comprising an exhaust manifold and an exhaust outlet and an intake manifold with an intake air inlet is described. A turbocharger comprising an exhaust gas turbine and a compressor, wherein the exhaust gas turbine is in fluid connection with the exhaust outlet to receive exhaust gas. An EGR mixer comprising a geometry for varying the ratio of fresh air to exhaust gas mixed in the EGR mixer is in fluidic connection with the compressor such that the compressor receives a mixture of fresh air and the exhaust gas. The compressor is in fluidic connection with the intake air inlet of the internal combustion engine.

Brief description of the accompanying drawings:
[0003] An embodiment of the disclosure is described with reference to the following accompanying drawings:
[0004] Figure 1 illustrates a block diagram of a mixer in electronic communication with an engine control unit; and
[0005] Figure 2 illustrates a mixer used in combination with an exhaust gas path of an internal combustion engine.

Detailed description of the embodiments:
[0006] A mixer 12 for an exhaust gas path is described. The mixer 12 comprises an actuator 14 adapted to be controlled by an engine control unit 16. A control rod 18 is coupled to the actuator 14, the control rod 18 adapted to translate when actuated by the actuator 14. At least one vane 20 is coupled to the control rod 18, the at least one vane 20 rotatable to vary an angle of attack when exhaust gas impinges on the at least one vane 20, wherein the angle of attack is dependent on an engine operating condition.

[0007] Figure 1 illustrates a block diagram 10 of a mixer 12 in electronic communication with an engine control unit 16. The mixer 12 is electronically connected with the engine control unit 16 via a control flow path 14. The mixer 12 disperses exhaust gas containing the reducing agent on to the catalytic converter. The engine control unit 16 facilitates dispersing exhaust gas containing the reducing agent on different sections of the catalytic converter depending on engine operating parameters, a mass flow rate of exhaust gas flowing through the mixer 12, and a quantity of reducing agent that is injected into the exhaust gas path as will be explained below.

[0008] Figure 2 illustrates a mixer 12 that is used in the exhaust gas path of the internal combustion engine. The mixer 12 comprises an actuator 14 which is actuated by the engine control unit 16 in accordance with an engine operating condition. The engine operating condition is dependent on at least one of an injection quantity, rail pressure, accelerator pedal position, engine speed, number of fuel injections per unit time, engine operating temperature, and engine coolant temperature.

[0009] A control rod 18 is coupled to the actuator 14, wherein the control rod 18 is adapted to translate when actuated by the actuator 14 through the engine control unit 16. At least one vane 20 is coupled to the control rod 18. The at least one vane 20 is coupled to the control rod 18 by means of a pivot to facilitate rotating the vane 20 about a horizontal axis. When the control rod 18 reciprocates due to actuation by the actuator 14, the vane 20 rotates about the horizontal axis. In an embodiment, a plurality of vanes 20 may be spaced axially apart from one another and coupled to the control rod 18. Each of the plurality of vanes 20 may rotate about the horizontal axis to vary the angle of attack based on the impinging mass flow rate of exhaust gas and the reducing agent from the internal combustion engine.

[00010] A pivot rod 22 is coupled to the pivot of the control rod 18. One end of the pivot rod 22 is coupled to the pivot of the control rod 18. An opposite end of the pivot rod 22 is coupled to a fixed support 24. The pivot rod 22 facilitates providing leverage when the control rod 18 reciprocates. When the control rod 18 is actuated in the downward direction, the pivot rod 22 moves in the downward direction. Due to the movement of the pivot rod 22 in the downward direction, the vane 20 is rotated in the upward direction, thereby decreasing the angle of attack to the incoming stream of exhaust gas and reducing agent. Similarly, when the control rod 18 is actuated in the upward direction, the pivot rod 22 moves in the upward direction. Due to the movement of the pivot rod 22 in the upward direction, the vane 20 is rotated in the downward direction, thereby increasing the angle of attack to the incoming stream of exhaust gas and reducing agent. The number of pivot rods 22 is equal to the number of vanes 20 of the mixer 12. Therefore, due to the mechanical actuation of each of the pivot rods 22 that are coupled between the pivot and the fixed support 24, each of the vanes 20 may be rotated correspondingly to increase or decrease the angle of attack to the incoming stream of exhaust gas and reducing agent.

[00011] The working of the mixer 12 is described as an example. Based on an engine operating condition, the actuator 14 is actuated by the engine control unit 16. Based on the actuation level of the actuator 14, the control rod 18 may be translated to a particular position. The translation of the control rod 18 facilitates setting an angle of attack of the vane 20. Based on the operating condition of the mixer 12 which is dependent on a mass flow rate of exhaust gas flow through the mixer 12, and a quantity of reducing agent that is injected into the exhaust gas path upstream from the mixer 12, the engine control unit 16 facilitates actuating the actuator 14 to increase or decrease the angle of attack of the vane 20. The vane 20 is adapted to rotate to increase an angle of attack when the mass flow rate of exhaust gas and the mass flow rate of reducing agent increases, thereby facilitating impinging the exhaust gas and reducing agent closer to an entry of the catalytic converter such that the exhaust gas flows through a larger length of the catalytic converter. Due to the larger mass flow rate of exhaust gas and reducing agent flowing through a larger length of the catalytic converter, a larger percentage of the exhaust gas and reducing agent gets effectively oxidized. Therefore, the efficiency of the catalytic converter is effectively enhanced. In a similar manner, the vane 20 is adapted to rotate to decrease an angle of attack when the mass flow rate of exhaust gas decreases to facilitate impinging the exhaust gas farther away from the entry of the catalytic converter such that the exhaust gas flows through a shorter length of the catalytic converter. Due to the smaller mass flow rate of exhaust gas and reducing agent flowing through a smaller length of the catalytic converter, an efficiency of the catalytic converter is increased. Therefore, the efficiency of the catalytic converter is effectively enhanced. Therefore, by varying the length of flow of the exhaust gas and reducing agent depending on the concentration of the exhaust gas and reducing agent, the efficiency of the catalytic converter may be suitably enhanced.

[00012] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.