Field of the invention
[0001]This invention relates to a method of controlling the temperature of urea
in a dosing module.
Background of the invention
[0002] NOx reduction is one of the techniques for emission control. In order to meet upcoming stringent emission norms, vehicles across all classes are required to meet the legislated emission requirements. In case of NOx reduced urea from a tank is dosed by an injector into the exhaust path. The temperature of urea is critical in order to ensure efficient NOx reduction.
[0003] Prior art patent application CN207474176U discloses a method for diesel exhaust urea dosing injector comprises a thick film heating resistor, the heating resistor and the housing, the thick-film heating resistor placed housing and potting epoxy encapsulation, said thick film heating resistor comprises a stainless steel substrate, the stainless steel substrate front side printed with an insulating medium, insulating medium printed resistor and electrically connected to the electrode, the electrode and the lead end of the welding, the top of the housing opened a vent hole and filling material, the filling material from the top of the housing is opened inwardly through stainless steel base plate mounting holes. The utility model has thermal conductivity fast, good heat dissipation, high power density, high mechanical strength, small size, and can achieve high power, long product life advantages.
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 controlling temperature of urea solution in a dosing module.
Detailed description of the embodiments
[0006] FIG. 1 illustrates a method of controlling temperature of urea solution in a dosing module. The method comprises detecting 102 by a temperature sensor the temperature of urea solution in a dosing module. A control unit receives 104 the detected temperature. The control unit then verifies 106 if the received temperature corresponds to a dosing temperature for NOx conversion. A heating element located on a dosing injector of the dosing module is actuated 108 by said control unit for controlling the temperature of the urea solution. The heating element may be any one of thermocouple and ceramic heating element
[0007]The disclosed method is used to for heating urea in a dosing module. A dosing module is used to dose urea into the exhaust path. The urea mixes with the exhaust to reduce NOx. Urea gets decomposed when heated beyond its melting point (approximately 132 deg Celsius) and forms compounds like biuret, beyond 160 deg Celsius it will decompose to NH3 through the steps of thermolysis and hydrolysis. Ammonia (NH3) formation during thermolysis is minimal in vapour phase (during which heat carried away from exhaust gas is taken by urea for further decomposition) and most of the decomposition takes place in exhaust path. Now, in order to increase thermolysis momentum for urea, temperature requirement is necessary to push urea molecules for decomposition. Urea will get heated to a temperature as determined by various factors like NOx conversion ratio. For the purpose of understanding let us assume that the maximum temperature (dosing temperature) for urea to be

heated be 80deg Celsius (By considering factor of safety with respect to melting point of urea that is 132 deg Celsius).
[0008] In order to control the temperature of urea in the dosing module, the temperature sensor detects 102 the temperature of urea in the dosing module. The control unit receives 104 the detected temperature. The control unit verifies 106 if the received temperature corresponds to a dosing temperature (in this case limit set as 80degC) for NOx conversion. A heating element is located on a dosing injector of the dosing module. The heating element is actuated 108 by the control unit for controlling the temperature of the urea solution so that the temperature of urea reaches 80deg Celsius for ensuring NOx conversion.
[0009]By controlling the temperature of urea, spray characterization of urea which depends on the momentum and kinetics is improved. As a result time taken for urea decomposition can be decreased when compared to urea at room temperature. By increasing the temperature of urea it is observed that there is reduction in biuret formation of resulting in better NOx conversion.
[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 solenoid or fuel filter 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.

CLAIMS
We Claim:
1. A method (100) of controlling temperature of urea solution in a dosing
module, said method comprising:
detecting (102), by a temperature sensor temperature of urea solution in said dosing module;
receiving (104), by a control unit said detected temperature;
verifying (106), by said control unit if said received temperature corresponds to a dosing temperature for NOx conversion; and
actuating (108), a heating element located on a dosing injector of said dosing module, by said control unit for controlling the temperature of said urea solution.
2. The method of claim 1, wherein said heating element is any one of
thermocouple and ceramic heating element.