Claims:We Claim:
1. A selective catalytic reduction (SCR) system (10) in a vehicle (11), said SCR system (10) comprising:
- a first SCR unit (12) positioned in an exhaust path (13);
- a second SCR unit (14) placed downstream said first SCR unit (12);
- a temperature sensor (16) positioned upstream said first SCR unit (12) in said exhaust path (13);
characterized in that:
- at least one dosing module (18) positioned downstream said temperature sensor (16) in said exhaust path (13), said at least one dosing module (18) and said first SCR unit (12) are operated when temperature detected in said exhaust path (13) is less than a predefined temperature.

2. The SCR system (10) as claimed in claim 1, wherein said first SCR unit (12) comprises zeolite compounds and said second SCR unit (14) comprises vanadium compounds.

3. The SCR system (10) as claimed in claim 1, wherein said first SCR unit (12) is a cylindrical structure with copper zeolite coating.

4. The SCR system (10) as claimed in claim 1, wherein said first SCR unit (12) and the second SCR unit (14) comprises a catalyst each, arranged in the form of a coating on an inert support.

5. The SCR system (10) as claimed in claim 1, wherein two said dosing modules (18 (a), 18(b)) are placed on either side of said first SCR unit (12) in said exhaust path (13).

6. The SCR system (10) as claimed in claim 1, wherein said predefined temperature is a temperature range calibrated, when said vehicle (11) is operating in at least one vehicle conditions comprising a low-load condition and a high-load condition.

7. The SCR system (10) as claimed in claim 4, wherein said first dosing module (18(a)) operates in a low-load condition and second dosing module (18(b)) operates in a high-load condition.

8. The SCR system (10) as claimed in claim 1, comprises said temperature sensor (16) and said at least one dosing module (18) are electronically controlled.
, 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 an electronic control unit to detect a wear of a clutch in a vehicle and a method thereof.

Background of the invention
[0002] vanadium SCR technology offers a low cost, robust and promising solution to meet legislative targets for non-road emission legislation like CEV stage IV and CPCB4+. We have a defined SCR system, which will use predominantly Vanadium SCR for meeting NOx conversion targets. When the temperature is a temperature range of 250-500 degrees. Unfortunately, high performance of vanadium catalyst is limited at temperature less than 250 0C.Due to low power density engines in India, engine out temperatures are on the lower side and it becomes difficult to meet performance targets with vanadium catalyst.

[0003] A Prior art document US7998423 discloses a selective catalytic reduction (SCR) filters that effectively provide simultaneous treatment of particulate matter and NOx. The SCR filter can include a fiber matrix wall flow filter comprising a plurality of non-woven inorganic fibers and a chabazite molecular sieve SCR catalyst on the fiber matrix wall flow filter. By combining a fiber matrix wall flow filter with a chabazite molecular sieve SCR catalyst, high catalyst loading can be achieved without causing excessive back pressure across the filter when implemented in emission treatment systems.

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 selective catalytic reduction (SCR) system in a vehicle in accordance with one embodiment of the invention; and
[0006] Fig.2 illustrates a selective catalytic reduction (SCR) system in a vehicle in accordance with one embodiment of the invention.

Detailed description of the embodiments
[0007] Fig.1 illustrates a selective catalytic reduction (SCR) system in a vehicle, in accordance with one embodiment of the invention. The SCR system 10 comprises a first SCR unit 12 positioned in an exhaust path 13 and a second SCR unit 14 placed downstream the first SCR unit 12. The SCR system 10 comprises a temperature sensor 16 positioned upstream the first SCR unit 12 in the exhaust path 13. Characterized in that, at least one dosing module 18 positioned downstream the temperature sensor 16 in the exhaust path 13. At least one dosing module 18 and the first SCR unit 12 are operated when a temperature detected in the exhaust path 13 is less than a predefined temperature.

[0008] Further, the construction of the SCR system 10 and the components of the SCR system 10 and their working are explained below. The vehicle 11 comprises an engine 22 connected to a diesel oxidation catalyst (DOC) 24 positioned in the exhaust path 13 in the vehicle 11. The DOC 24 is used to convert the exhaust gas emitting from the engine 22 during the working of the vehicle 11. The working of the DOC 24 and the engine 22 is very well known in the state of the art, so hereby, the working and the construction of the engine 22 and the DOC 24 is not explained in the present document. The first SCR unit 12 and the second SCR unit 14 comprises a catalyst each, arranged in the form of a coating on an inert support(not shown). The first SCR unit 12 comprises zeolite compounds and the second SCR unit 14 comprises vanadium compounds. The catalyst composition is selected from the group consisting of the oxides of vanadium, niobium, molybdenum, iron and copper.

[0009] According to one embodiment of the invention, the first SCR unit 12 is a cylindrical structure with copper zeolite coating. For instance, on an inert ceramic honeycomb, the coating containing the first SCR unit 12 catalyst is applied up along the length of the inert support by a conventional dipping process as known to a person skilled in the art. However, the first SCR unit 12 catalyst coating is not restricted to copper zeolite, but can be chosen from a group of zeolite compounds comprising silver (Ag), gold (Au) or platinum (Pt) and the like. The second SCR unit 14 catalyst has a coating of vanadium compounds.

[0010] Fig.2 illustrates a selective catalytic reduction (SCR) system in a vehicle in accordance with one embodiment of the invention. The first SCR unit 12 and the second SCR unit 14 are placed in series in the exhaust path 13. The SCR system 10 comprises two dosing modules 18 (a), 18 (b) placed on either side of the first SCR unit 12 in the exhaust path 13. A first dosing module 18 (a) is placed upstream the first SCR unit 12 and the second dosing module 18(b) is placed downstream the first SCR unit 12 and upstream the second SCR unit 14. The first SCR unit 12 is designed to operate in a predefined temperature range and the second SCR unit 14 is designed to operate in another predefined temperature range. For instance, the first SCR unit 12 is operated in temperature range from 180degrees- 250 degrees, wherein the second SCR unit 14 is operated in the temperature range from 250 degrees- 500 degrees.

[0011] The predefined temperature is a temperature range calibrated, when the vehicle is operating in at least one vehicle conditions comprising a low-load condition and a high-load condition. During, the low-load condition, the temperature of the exhaust gas in the exhaust path 13 ranges from 180degrees-250 degrees, where the first SCR unit 12 is operated. During the high load conditions, where the temperatures in the exhaust path 13 exceeds beyond 250degrees, then the second SCR unit 14 is operated.

[0012]According to one embodiment of the invention, the first dosing module 18(a) operates in the low-load condition and the second dosing module 18(b) operates in the high-load condition. The dosing module 18 doses the urea/ammonia content during the conversion process to reduce the harmful gas emissions. According to another embodiment of the invention, when the system 10 uses only one dosing module 18 , the dosing module 18 is positioned upstream first SCR unit 12 as shown in the figure 1, such that, the dosing module 18 doses a higher volume of urea compared to the amount of urea dosed in the double dosing process.

[0013]The SCR system 10 comprises a control unit 20 connected to the temperature sensor 16 and to the at least one dosing module 18. During the normal operating conditions of the vehicle 11, the temperature sensor 16 detects the temperature of the exhaust gas and transmits a signal to the control unit 20. The control unit 20 upon detecting the temperature received, activates the at least one dosing module 18 in the system 10.

[0014]If the system is using a double dosing technique with two dosing modules 18 (a), 18(b) and when the control unit 20 detects a temperature less than 250 degrees (predefined temperature) , activates the first dosing module. The ammonia mixed in the exhaust gas passes through the first SCR unit 12 and the exhaust gas undergoes the conversion process. The exhaust gas having the temperature less than the 250 degrees is efficiently converted into the non-harmful gases in the first SCR unit 12 due to the copper zeolite coating on the honeycomb like structure. After the conversion process is completed in the first SCR unit 12, the filtered exhaust gas passes through the second SCR unit 14 and then into the atmosphere.

[0015]Wherein, when the temperature of the exhaust gas is more than the predefined temperature i.e., more than 250 degrees, the control unit 20 activates both the first dosing module 18(a) and the second dosing module 18(b) simultaneously. The volume of the ammonia dosing into the exhaust path 13 through the first and the second dosing modules 18(a), 18(b) is divided as per the requirement by the control unit 20. The exhaust gas is made to pass through the first SCR unit 12. Due to the high temperature of the exhaust gas, the conversion process will not be efficient in the first SCR unit 12. The partially converted exhaust gas along with the ammonia (released from first and second dosing modules 18(a), 18(b)) is made to pass through the second SCR unit 14. Due to the vanadium compounds present in the second SCR unit 14, the conversion of the exhaust gas into the non-harmful gases are efficient.

[0016]With the above system and the method, the conversion process of the exhaust gas into the non-harmful gases will be efficient. The system 10 provides a simple, cost-effective solution as the use of exclusively zeolite-based SCR catalyst systems is very expensive, because of the high raw material prices for zeolites. The usage of the copper zeolite not only helps in oxidizing the nitrogen oxides during the conversion process, but also helps in storing the ammonia during the cold-start.

[0017]The dosing of the ammonia upstream first SCR unit 12 at lower quantities of Diesel effluent fluid (DEF) (as it is expected to operate at low load conditions), and the dosing of the ammonia upstream second SCR unit 14 during higher DEF quantities helps in increasing field robustness of exhaust path as double dosing would reduce the risk of crystallization / deposits. The emission compliance is efficiently achieved for low temperature and for high temperature operating conditions by the above-disclosed system 10.

[0018] 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.