Claims:We Claim:
1. A method of monitoring emission in an exhaust gas system, said exhaust gas system comprising at least a NOx sensor located along an exhaust flow path, said method comprising:

receiving (100), by a control unit concentration of NOx from said NOx sensor;

comparing (102), by said control unit said received concentration of NOx with respect to threshold defined in a data map;

checking (104), by said control unit difference between said received concentration and said threshold defined in said data map; and

displaying (106), by said control unit onto a display device, said difference for monitoring emission in said exhaust gas system.

2. The method of claim 1, wherein said display device is at least one of a hand held device and on-board display device.
, 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]This invention relates to the field of monitoring exhaust emission in an exhaust gas system.

Background of the invention
[0002] On-board diagnostic requirement monitoring the injection timing of the fuel injection system with respect to emission requirement will be mandatory once bharat stage VI emission norms kick-in. In this scenario there is a need to determine the concentration of exhaust in real time to an alert the user of a vehicle about any deviations.

[0003] Prior art patent application DE3823494A1 relates to a method and a device for obtaining parameters correlated with target variables of a combustion system, in which target variables are repeatedly measured and measurement parameters, or combinations of parameters, determined directly from the optical and thermal observation of the combustion are combined for the purpose of describing the target variables. The measurement parameters, or combinations of parameters, correlated with the target variables are determined. The functional relationship between the target variables and the measurement parameters or combinations of parameters is determined with the aid of a learning, self-adaptive method

Brief description of the accompanying drawing
[0004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0005] FIG. 1 illustrates a method of monitoring emission in an Exhaust gas system.

Detailed description of the embodiments
[0006] FIG. 1 illustrates a method of monitoring emission in an exhaust gas system. The exhaust gas system comprises at least a NOx sensor located along an exhaust flow path. The method comprises receiving 100, by a control unit concentration of NOx from the NOx sensor. The control unit compares 102 the received concentration of NOx with respect to threshold defined in a data map. The control unit checks 104 the difference between the received concentration and the threshold defined in the data map, and the control unit displays 106 difference for monitoring emission in the exhaust gas system. In an embodiment the display device is at least one of a hand held device and on-board display device

[0007]The working of the above mentioned method will be explained in further detail. The working of the above mentioned method will be explained in further detail. The exhaust gas system disclosed herein comprises at least a NOx sensor located along the exhaust flow path. At step 100, the control unit receives the concentration of NOx from NOx sensor. At step 102, the control unit compares the received concentration of NOx with respect to threshold defined in a data map. At step 104, the control unit check the difference between the received concentration and the threshold defined in the data map. At step 106, the control unit displays onto a display device the above mentioned difference for monitoring emission in the exhaust gas system. The control unit relies on a signal from a speed sensor to estimate the actual injection timing of the fuel. This is then compared with the injection timing from a data map. The difference injection timing is used as an input for monitoring emissions.

[0008]Consider the example of an exhaust gas system wherein the mass flow of exhaust is 5g/hr. Now this mass flow is first measured by the NOx sensor located along the exhaust flow path. The control unit receives 100 the concentration of NOx from the NOx sensor. Now the concentration of 5g/hr is compared against a threshold, the threshold is defined based upon the fuel injection quantity. Now it is assumed that the threshold is 2g/hr. This indicates that for the same fuel injection quantity, there is higher mass flow of exhaust. The control unit checks for the difference between the received concentration and the threshold defined in the data map. This difference is now displayed by the control unit onto a display device for monitoring emission in the exhaust gas system.

[0009]It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of the type of exhaust system used. 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.