Claims:We Claim:
1. An electronic control unit (10) to reduce a temperature of a dosing module (25) in a vehicle, said control unit (10) adapted to :
- detect a temperature at an upstream (24) of a diesel oxidation catalyst (DOC) (14) during at least one vehicle operating condition, in a regenerative mode ;
- operate a compressor assembly (17) connected to said engine (16), to increase an load on said engine (16) for a higher combustion temperature in said engine (16), when said detected temperature at said DOC (14) is less than a predefined temperature;
characterized in that :
- said electronic control unit (10) adapted to operate an electronically controlled valve ( 21) connected between said compressor assembly (17) and a dosing module (25) , to allow air compressed in said compressor assembly (17) onto said dosing module (25) to reduce said temperature of said dosing module (25).

2. The control unit (10) as claimed in claim 1, wherein said air compressed in said compressor assembly (17) is stored in a compressor tank (19) and is directed towards said dosing module (25) via a flow path (30).

3. The control unit (10) as claimed in claim 2, wherein said electronically controlled valve (21) is placed in said flow path (30) which connects said compressed tank (19) and said dosing module (25).

4. The control unit (10) as claimed in claim 1, wherein said compressor assembly (17) further comprises a nozzle (23) connected at one end of said flow path( 30) to allow said air compressed in said compressor assembly (17) onto said dosing module (25).
5. The control unit (10) as claimed in claim 4, wherein said air compressed in said compressor assembly (17) is blown over a dosing module (25) via said nozzle (23).

6. The control unit (10) as claimed in claim 1, wherein said electronically controlled valve ( 21) is a uni-directional valve.

7. The control unit (10) as claimed in claim 1, further comprises a temperature sensor (20) adapted to sense said temperature at said DOC (14) in said regenerative mode.

8. The control unit (10) as claimed in claim 1, wherein said control unit (10) adapted to inject fuel into said engine (16) to operate a compressor (18) during said at least one vehicle operating condition.

9. The control unit (10) as claimed in claim 1, wherein said at least one vehicle operating condition is chosen from any one of the following conditions comprising a low-speed condition and a low-load condition.

10. A method of reducing a temperature in an exhaust system (12) of a vehicle, said method comprising :
- detecting a temperature at a diesel oxidation catalyst (DOC) (14), during at least one vehicle operating condition, using a temperature sensor (20) in a regenerative mode;
- increasing a load on an engine (16) of said vehicle by operating a compressor assembly (17), when said detected temperature at said DOC (14) is less than a predefined temperature;
characterized in that :
- operating an electronically controlled valve (21) for allowing air compressed in said compressor assembly (17) onto a dosing module (25) to reduce said temperature in said dosing module (25).
, 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 reduce a temperature of a dosing module in a vehicle and a method thereof.

Background of the invention
[0002] In India, from 2020, with the implementation of BS6 emission legislation, the usage of diesel particulate filter (DPF) is mandatory for all class of vehicles in order to meet particulate matter number targets. With the use of DPF, regeneration occurs to clean the soot accumulated in the DPF. During regeneration, an exhaust temperature in and down-stream DPF can reach approximately to 620degC. Due to exhaust gas treatment packaging in commercial vehicles, the urea-dosing module is exposed to these high temperatures. In addition to that, due to cost, customers tend to select an air-cooled dosing module. These dosing modules (which have max allowed temperature of ~120degC) are at border condition with respect to dosing tip temperatures, especially in low exhaust flow, high exhaust temperature and in high ambient temperature conditions.
[0003] A Prior art document DE102009047375 discloses a device for cooling dosing module. The device comprises a dosing module , which is assigned a cooling unit, by which a coolant is flowed through, and a cooling body encloses a lateral surface of the dosing module. The coolant or the reducing agent circulates in the cooling body of the internal combustion engine. A cooling spiral is provided, which is embedded with heat transition casting material, such as tin solder, additives of silicon oil, zinc oxide, aluminum, copper, silver or thermoplastic plastic.

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 an electronic control unit in a vehicle in accordance with one embodiment of the invention; and
[0006] Fig. 2 illustrates a method of reducing a temperature in an exhaust system of a vehicle in accordance with one embodiment of the invention.

Detailed description of the embodiments
[0007] Fig.1 illustrates an electronic control unit 10 in a vehicle, in accordance with one embodiment of the invention. The electronic control unit 10 to reduce a temperature in an exhaust system 12 of a vehicle, is adapted to detect a temperature at an upstream 24 of a diesel oxidation catalyst (DOC) 14 during at least one vehicle operating condition, in a regenerative mode . The control unit 10 is adapted to operate a compressor assembly 17 connected to the engine 16, to increase a load on the engine 16 for a higher combustion temperature in the engine 16, when the detected temperature at the DOC 14 is less than a predefined temperature. The control unit 10 adapted to operate an electronically controlled valve 21 connected between the compressor assembly 17and a dosing module 25 , to allow air compressed in the compressor assembly 17 onto the dosing module 25 to reduce the temperature of the dosing module 25 .

[0008] Further the construction of the electronic control unit 10 and the exhaust system 12 in a vehicle and the working of the components of the exhaust system 12 are explained below. The compressor assembly 17 comprises a compressor 18 and a compressor tank 19 as shown in the figure 1. The air compressed in the compressor 18 is stored in the compressor tank 19. The compressor assembly 17 further comprises a flow path 30 connecting the compressor assembly 17 and the dosing module 25. The compressor assembly 17 further comprises a nozzle 23 connected at one end of the flow path 30, proximity to the dosing module 25. The electronically controlled valve 21 is placed in the flow path 30 that connects the compressor tank 19 and the dosing module 25, such that, the control unit 10 is adapted to close or open the valve 21 based on the requirement. The electronically controlled valve 21 is a uni-directional valve. The compressed air from the compressed tank 19 is blown over the dosing module 25 via the nozzle 23, to reduce the temperature of the dosing module 25. The flow path 30 made between the compressor tank 19 and the dosing module 25 protrudes through the canning and is angled towards a tip of dosing module 25. A portion of dosing module 25 is insulated, such that, the temperatures of the exhaust system 12 will not damage the tip. According to one embodiment of the invention, the dosing module 25 is an air-cooled dosing module.

[0009] The electronic control unit 10 further comprises a temperature sensor 20 adapted to detect the temperature upstream 24 of the DOC 14. At least one operating conditions is chosen from any one of the following operating conditions comprising a low-speed condition and a low-load condition. During the regenerative mode, when the vehicle is operating in the low-speed condition or low-load condition, the temperature at upstream 24 of the DOC 14 reduces beyond the predefined temperature, which reduces the conversion process of hydrocarbons (present in the post-injected fuel) into an exothermal energy. To improve the conversion process and to increase a temperature in a diesel particulate filter (DPF) 22 of the exhaust system 12, for a soot oxidization, the electronic control unit 10 maintains the temperature at upstream 24 of DOC 14 above the predefined temperature.

[0010] The connection and working of the engine 16 operating the compressor 18 is known to a person skilled in the art. The compressor 18 disclosed above could be a mechanically operated or an electrically operated compressor. For instance, in the mechanically operated compressor 18, the control unit 10 engages a clutch of the compressor 18 (which is connected to the engine 16) continuously, to increase the load on the engine 16, upon detecting the temperature at upstream 24 of the DOC 14 less than the predefined temperature, during at least one vehicle operating condition. The engaged compressor 18 adapted to compress the atmospheric air and is stored in the compressor tank of the compressor assembly 17. The control unit 10 connected to engine 16 and to the compressor 18, adapted to control at least one operating condition of the engine 16 and the compressor 18 during the regenerative mode. The control unit 10 adapted to inject fuel into the engine 16 to operate the compressor 18, during the low-load or low-speed condition. The control unit 10 is chosen from a group of control units comprising a microprocessor, a microcontroller, an integrated chip and the like. According to one embodiment of the invention, the electronic control unit 10 is an engine control unit.

[0011] Fig. 2 illustrates a method of reducing a temperature in an exhaust system of a vehicle according to one embodiment of the invention. In step S1, a temperature at a diesel oxidation catalyst (DOC) 14 is detected, during at least one vehicle operating condition, using a temperature sensor 20 in a regenerative mode. In step S2, a load on an engine 16 of the vehicle is increased by operating a compressor assembly 17, when the detected temperature at the DOC 14 is less than a predefined temperature. In step S3,
an electronically controlled valve 21 is operated for allowing air compressed in the compressor assembly 17 onto a dosing module 25 to reduce the temperature of the dosing module 25.

[0012] A detailed description of the method of reducing the temperature of the dosing module is explained as follows. The regenerative mode is activated in the vehicle based on an amount of the soot accumulated at the DOC 14. In the regenerative mode, when the vehicle is in the idling or low –speed or low-load condition, the temperature at the upstream 24 of the DOC 14 is reduced, thus reducing the conversion process of hydrocarbons present in the post-injected fuel and further reducing the temperature in the diesel particulate filter (DPF) 22. The control unit 10 upon detecting the temperature at upstream 24 of the DOC 14 being less than the predefined temperature increases the load on the engine 16. According to one embodiment of the invention, the temperature at the upstream 24 of the DOC 14 should be maintained above 220 degrees Celsius, thus the temperature in the DPF 22 reaches to 600 degrees Celsius, which is efficient to oxidize the soot accumulated in the DPF 22.

[0013] When the control unit 10 detects the temperature at upstream 24 of the DOC 14 less than or equal to 220 degrees, then the control unit 10 engages the compressor 18 which is connected to the engine 16. To operate the compressor load 18, the control unit 10 injects the fuel into the engine 16, thus increasing the combustion temperature in the engine 16. Due to the higher combustion temperature in the engine 16, the temperature at the upstream 24 of the DOC 14 increases more than the predefined temperature during the low-load or low-speed condition. (i.e., it increases more than 220 degree Celsius). The control unit 10 engages the compressor 18 until the load on the engine 16 or speed of the engine 16 is increased.

[0014] The compressor 18 upon operated in the regenerative mode, compressed the air and the compressed air is stored in the compressed tank 19. The control unit 10 is adapted to open the valve 21 during this process to allow the compressed air to flow onto the dosing module 25 via the flow path 30 and the nozzle 23. The pressure of the compressed air being high, is blown over the dosing module 25 and the temeprture at the tip of the dosing module is reduced. For instance, the temperature of the dosing module 25 is reduced below 160 degree Celsius, with the compressed air. The compressed air is blown over the dosing module 25 during at least one of the following conditions like during a low fuel flow condition or when a high DPF downstream temperature is detected in the regeneration mode or during high ambient temperatures. Due to the compressed air being blown over the dosing module 25, the dosing module temperature is reduced . The control unit 10 is adapted to close the valve 23 to discontinue the flow of the compressed air onto the dosing module 25 for every predefined time interval or when the above disclosed process is completed.

[0015] With the above disclosed method, a regeneration process in the vehicle is not interrupted, as DOC 14 upstream temperature is maintained above the predefined temperature which is critical during a city driving condition or where a low speed and a low load driving conditions are prevalent. With the reduction in interruptions in the regeneration process, dependent factors such as oil dilution, increase in the fuel consumption are reduced. The air compressed during the regenerative mode is efficiently used to reduce the temperature of the dosing module 25.

[0014] 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