Claims:We Claim:
1. A method of detecting filter clogging in a supply module of a dosing system, said dosing system comprising at least a supply module and a dosing module, said supply module comprising a filter and a pump, said method comprising:

receiving (100), by a control unit a magnitude of duty cycle supplied to said pump and pressure of said dosing system;

determining (102), by said control unit load on said filter based on said duty cycle and said pressure;

determining (104), by said control unit, from a data map the requirement of filter change;

indicating (106), by said control, the filter replacement requirement.

2. The method of claim 1, further comprising receiving by said control unit speed of said pump and current drawn by the said pump.

3. The method of claim 1, further comprising indicating said requirement onto an instrument cluster of a vehicle.
, 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 detecting filter clogging in a supply module of a dosing system.

Background of the invention
[0002] DNOx system is used for reduction of NOx from the exhaust, before the exhaust is sent to the atmosphere. The system comprises a tank that stores diesel exhaust fluid (DEF), from the tank the DEF flows to a supply module where DEF is filtered and pressurized, then sent to the dosing module for injection at upstream the SCR catalyst. The filter is susceptible to clogging and over a period of time the flow of DEF from the supply module to dosing module may be affected due to clogging of the filter in the supply module.

[0003] Prior art patent application US 9199198 discloses a method pertaining to SCR systems for exhaust cleaning whereby liquid is supplied to a feed device via which it is supplied to a dosing unit at a consumption point of the SCR system. The method includes continuously determining cumulative amounts of liquid dosed via the dosing unit. Need for replacement or cleaning of a filter unit for said liquid is also determined on the basis of the cumulative amounts of liquid dosed. The method further includes dosing at least part of the liquid supplied via the feed device and feeding un-dosed liquid back in a return flow to enable it to be supplied again to the feed device. Also disclosed is a computer program product that includes code for a computer for implementing the disclosed 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 detecting filter clogging in a supply module of a dosing system.

Detailed description of the embodiments
[0006] FIG. 1 illustrates a method of detecting filter clogging in a supply module of a dosing system. The dosing system comprises at least a supply module and a dosing module, the supply module comprises a filter and a pump. A filter in the dosing module is limited in terms of capacity of dust that can be store in the filer, for example the maximum dust holding capacity of the filter may be 12grams. The method comprises, receiving (100), by a control unit a magnitude of current, duty cycle and the speed of the pump with different filter loading conditions. Also system performance, mainly the system pressure will be monitored for each case of loading. Model to predict the filter loading will be developed based on the above mentioned pump and system parameters

[0007]The working of the above mentioned method will be explained in further detail. The supply module receives DEF from a tank. The DEF that is stored in the supply modules needs to be supplied to the dosing module. Actuating duty cycle signal based on the system pressure is supplied to the supply module for enabling the pump to operate and DEF to flow from the supply module into the dosing module. At step 100, the magnitude of duty cycle supplied to the pump is received by the control unit. At step 102, the control unit determines the filter loading based on the model developed and also evaluates if the filter change is required for the upcoming vehicle service. Prediction of service requirement is based on the data acquired by the vehicle drive pattern and comparing it with the filter load. For occurrence of every service interval an indication on the cluster or to the fleet owner will be given based on loading of filter and requirement of filter change. Also, the requirement of filter change may be indicate on the cluster or to the fleet owner based on the filter loading data.

[0008]The pump performance will be monitored based on the current drawn, duty cycle of pump actuation and the speed of operation. The system pressure behaviour during ideal non loaded filter conditions will be used as reference in the disclosed method and this will be used to predict the amount of clog or the particle accumulation in the filter. Based on the output data from the model, the proposed method will analyze the requirement for the filter change in the upcoming vehicle service. The proposed method also indicates the distance which can be covered further without main filter replacement ensuring normal DNOX system performance based on the data analysis of the travel map of vehicles with different filter loads available.

[0009]With the use of the above mentioned method it is now possible to determine clogging in the filter of the supply module in the dosing system. An indication may be provided for notifying the user of the vehicle if the filter needs to be replaced.

[0010]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 dosing 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.