Claims:We Claim:
1. An apparatus (100) for measuring uniformity index of exhaust gases, in SCR exhaust after treatment system, comprising a housing (102) defining an exhaust flow path positioned in line with the SCR catalyst (112), comprising:
an indexing plate (104) comprising a plurality of measuring positions (105);
a measuring probe (106) extends from the housing (102) and elongates through the exhaust flow path towards the SCR catalyst (112) and adapted to move along with a movable strut (108);
an indexing lever (110) connected with the measuring probe (106) and adapted to manually positioning the measuring positions (105) on the indexing plate (104), wherein the indexing plate (104) is calibrated in a way that, when the indexing lever (110) is positioned on the indexing plate (104), corresponding change in location is setup at the measurement tip of the measuring probe (106).

2. The apparatus (100) as claimed in claim 1, wherein the movable strut (108) is further adapted to extend and retract the measuring probe (106) to vary the location of the probe in the exhaust flow path.

3. The apparatus (100) as claimed in claim 1, wherein the exhaust probe is moveable to a plurality of locations within a portion of a sectional area of the exhaust flow path through a combination of rotation of the measuring probe (106) and extension and retraction of the movable strut (108).

4. The apparatus (100) as claimed in claim 1, wherein the apparatus (100) is further adapted to read ammonia (NH3) uniformity across the surface of the SCR catalyst in quick successions.

5. The apparatus (100) as claimed in claim 1, wherein the apparatus (100) is a manually operated hand-held device to measure ammonia uniformity after SCR of the exhaust system mounted on an engine test bench
, Description:Complete Specification:

The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] The invention relates to an apparatus for measuring uniformity index of exhaust gases, in SCR exhaust after treatment system of a vehicle.

Background of the invention
[0002] Selective catalytic reduction (SCR) systems depend upon the injection of ammonia or urea, or sometimes an alternate reductant such as hydrocarbons, into the system. The injected reductant processes in the exhaust gas, ultimately entering the gas phase and adsorbing to the catalyst surface for reaction with adsorbed NOx from the engine. The uniformity profile of injected and processed reductant is a part of the performance of the after treatment systems, and designs having lower uniformity ultimately require relatively larger catalysts and/or catalyst loadings to meet the emission legislation requirements of the application.

[0003] In addition, the catalyst reaction efficiency is directly affected by the uniformity index hence, the uniformity index (UI) of the reductant is very important and is the basis for system optimization. The UI of the reductant is an indicator of the NOx conversion efficiency and good UI values can support in optimized volume of catalyst and loading. . Therefore, improving the UI can reduce the cost of producing a catalytic converter, which are expensive due to the high prices of the precious metals contained therein. Accordingly, measurement of the UI is an important process in the development of catalytic systems. The determination of the uniformity is a challenging operation, and can require a large amount of design effort and numerous design iterations. Commonly used methods, such as computational fluid dynamics (CFD) operations allow multiple systems to be tested and adjusted, but do not always match real systems. The design optimization can be achieved by CFD simulations by predicting flow characteristics and the optimized design is arrived when the uniform distribution of exhaust gas over SCR catalyst is achieved. Moreover, before CFD, a narrowed down DoE is tested on engine bench to understand the UI behavior patterns and this test done in conventional methods which consume huge effort in terms of man hours and adaptations. Therefore, further technological developments are desirable in this area

[0004] A patent document CN105445422A discloses method for measuring the engine gas mixing uniformity, characterized by comprising the following steps: First, a plurality of measuring points were measured intake inlet of the intake manifold and the intake manifold of the plurality of cylinders at the inlet methane, ethane or propane concentration; secondly, the uniformity of the gas at the inlet of a gas cylinder uniformity of the intake manifold is calculated for each measuring point at the inlet and the respective intake manifolds.

Brief description of the accompanying drawings:
[0005] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0006] FIG. 1 illustrates an apparatus for measuring uniformity index of exhaust gases, according to an embodiment in the invention.

Detailed description of the embodiments
[0007] Figure 1 illustrates an apparatus (100) for measuring uniformity index of exhaust gases, according to an embodiment of the disclosure. The implementation of the apparatus 100 is in SCR exhaust after treatment system of a vehicle. The apparatus 100 for measuring uniformity index of exhaust gases comprises a housing 102 defining an exhaust flow path positioned in line with a SCR catalyst 112. The apparatus 100 further comprises an indexing plate 104, a measuring probe 106, and an indexing lever 110. Each component is described in further detail below.
[0008] The housing 102 of the apparatus 100 is defining an exhaust flow path positioned in line with the SCR catalyst 112. The indexing plate 104 is comprising a plurality of measuring positions represented by reference numeral 105. The exhaust gases from the engine enters the SCR catalyst 112 through immediate components of the exhaust after treatment system. As the exhaust gases passes through the SCR catalyst 112, there will be NOx deposition on the substrate of the catalyst 112. In one embodiment, indexing plate 104 is comprising the plurality of measuring positions 105 are numbered as naming of the positions in the indexing plate. The numbered positons may be used for calibration in the indexing mechanism.

[0009] The plurality of measuring positions 105 may be used for the measurement of NOx deposition with the measuring probe 106. The measuring probe 106 is clamped to the apparatus 100. Further, the measuring probe 106 extends from the housing 102 and elongated to the SCR catalyst 112 into the exhaust flow path and adapted to move along with a movable strut 108. The movable strut 108 is further adapted to extend and retract the measuring probe 106 to vary the location of the probe in the exhaust flow path.

[0010] In one embodiment, the measuring probe 106 is connected and extended from the housing via flexible coupling. The movable strut 108 is connected with assembly of links or joints or bushings or bearings or the like, that allow the strut 108 to move up and down independently and turn left or right together. In one embodiment, the movable strut 108 is connected with the housing 102 via a ball joint.

[0011] In construction the measuring probe 106 has a first end 106a and a second end 106b, as shown in Fig. 1. The first end 106a is connected to the indexing plate 104 and the second end is extended towards the SCR catalyst 112. According to one embodiment of the disclosure, in the apparatus 100, the housing 102 accommodates the second end 106b and extends it to the SCR catalyst 112 via exhaust flow path. The housing 102 is not limited to any particular shape but able to accommodate the measuring probe 106.

[0012] In one embodiment, the measurement of the NOx depositions in the SCR catalyst 112 is possible for various dimensions of SCR brick portfolios available in market. For bricks where the diameter is bigger than the diameter of the apparatus 100, measurement of the uniformity index is achieved by the modifications of the strut 108. The movable strut 108 is allowed to tilt along its axis for which a slot is designed to provide a provision for the tilting.

[0013] The apparatus 100 will help in measurement of localized NOx deposits with help of indexing mechanism. The indexing lever 110 when adjusted on the indexing plate 104, moves the measuring probe 106 to corresponding location on the SCR brick and the NOx ppm numbers are measured to understand the uniformity index behavior at each of the locations as calibrated on the indexing plate 104. By this indexing mechanism, the apparatus 100 enables reading of ammonia (NH3) uniformity across the surface of SCR catalyst 112 in quick successions.

[0014] The indexing lever 110 is connected with the measuring probe 106 and adapted to manually positioning the measurement points on the indexing plate 104. The indexing lever 110 is connected with the measuring probe 106 which positions the measurement tip after the SCR catalyst 112. The indexing plate 104 is calibrated in a way that, when the indexing lever 110 is positioned on the indexing plate 104, corresponding change in location is setup at the measurement tip of the measuring probe 106. The apparatus 100 determine degree of homogeneity at various measuring positions 105 in accordance with the concentration of exhaust gases, determines the uniformity of the mixer according to the mixing uniformity and difference. In one embodiment, the apparatus 100 is a manual hand held machine to measure ammonia (NH3) uniformity after SCR of the exhaust system mounted on an engine test bench.

[0015] ‘Adapted’ or ‘arranged’, in the context of the instant disclosure, refers to the technical capability or the technical capacity of a component, in relation to which the term ‘adapted’ or ‘arranged’ is used, to carry out or executed a specified action or actions, upon the requirement of the specified action or actions to be carried out or executed. Moreover, the usage of the term ‘adapted’ or ‘arranged’ here, is in reference with the normal technical capability or technical capacity of the component, imparted by the design or the structure or the composition of the component, and not in reference with any special or extraneous capability or capacity, beyond the scope of the normal technical capability or technical capacity. Therefore, there is a need to address this problem

[0016] 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.