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 a defrosting plate for a urea dosing pump, and more specifically to the defrosting plate that comprises a plurality of heating coils that are integrated within the defrosting plate of the urea dosing pump.

Background of the invention
[0002] JP 2008248710 A2 describes a urea based reducing agent addition system capable of adequately determining defrosting of urea aqueous solution in the entire system including a feed pipe. The temperature of urea aqueous solution in a storage tank is detected by a temperature-sensing type urea sensor, the concentration of urea contained in the urea aqueous solution is detected and defrosting of urea aqueous solution in the storage tank is determined based on the detected temperature and concentration. When determining the freezing, a feed pump is operated, the pressure on its output side is detected, and the defrosting in the pipe of a urea aqueous solution feed system is determined based on the detected pressure to determine the defrosting as the entire system.

Brief description of the accompanying drawing
[0003] Figure 1 illustrates a defrosting plate of a urea dosing pump that comprises a plurality of heating coils that are integrated therein in one embodiment of the invention.

Detailed description of the embodiments
[0004] Figure 1 illustrates a urea dosing pump 10. The urea dosing pump 10 comprises a housing 12. The housing 12 is adapted to receive a urea based reducing agent therein, wherein the urea based reducing agent freezes within the housing 12. An electrical resistance coil 14 is integrated within a plastic molding frame 16 such that the plastic molding frame 16 circumscribes the electrical resistance coil 14, wherein the plastic molding frame 16 that encapsulates the electrical resistance coil 14 is inserted within the housing 12. A plurality of screws 18 are inserted through a plurality of bores 20 that each extend from a first end 21 of the plastic molding frame 16 to an opposite second end 23 of the plastic molding frame 16. Each of the plurality of screws 18 that are inserted through each of the plurality of bores 20 of the plastic molding frame 16 is screwed on to each bore of a plurality of bores 26 that are defined in the housing 12 of the urea dosing pump 10. An outer cover 22 is positioned within the housing 12, the outer cover 22 proximate to the plastic molding frame 16 and secured to the housing 12 of the urea dosing pump 10 to constitute a unitary assembly.

[0005] Figure 1 illustrates a urea dosing pump 10. The urea dosing pump 10 comprises a housing 12. The housing 12 is adapted to receive a urea based reducing agent therein that is pressurized within the housing 12 of the urea dosing pump 10 and therein delivered to a dosing module for dosing the urea based reducing agent into an exhaust gas flow path of an internal combustion engine. When the urea dosing pump 10 is switched off, under cold temperature conditions the urea based reducing agent freezes within the housing 12 and accumulates within cavities located in the housing 12 of the urea dosing pump 10. The urea based reducing agent is therefore required to be thawed when the urea dosing pump 10 is operated once more due to the activation of the engine. In an exemplary embodiment, an electrical resistance coil 14 is positioned within a plastic molding frame 16 such that the electrical resistance coil 14 is integrated within the body of the plastic molding frame 16. More specifically, the electrical resistance coil 14 is integrated within the body of the plastic molding frame 16 such that the plastic molding frame 16 circumscribes the electrical resistance coil 14. Once the electrical resistance coil 14 is encapsulated within the body of the plastic molding frame 16, the plastic molding frame 16 that encapsulates the electrical resistance coil 14 is positioned within the housing 12 of the high-pressure fuel pump 10. Once the plastic molding frame 16 that encapsulates the electrical resistance coil 14 is positioned within the housing 12 of the high-pressure fuel pump 10, a plurality of screws 18 are inserted through a plurality of screw threads that are each defined through each of the plurality of bores 20 that each extend from a first end 21 of the plastic molding frame 16 to an opposite second end 23 of the plastic molding frame 16. Each of the plurality of screws 18 that are inserted through each of the plurality of bores 20 that each extend from the first end 21 of the plastic molding frame 16 is screwed on to screw threads that are defined in each of the plurality of bores 26 that are defined in the housing 12 of the urea dosing pump 10. Therefore, each of the plurality of screws 18 that are inserted through each of the plurality of bores 20 that each extend from the first end of the plastic molding frame 16 and is screwed on to mating screw threads that are defined in each of the plurality of bores 26 that are defined through the housing 12 of the urea dosing pump 10 facilitate securing the plastic molding frame 16 encapsulating the electrical resistance coil 14 within the housing 12 of the urea dosing pump 10. Thereafter, an outer cover 22 is positioned within the housing 12 and proximate to the plastic molding frame 16, and thereby secured to the housing 12 of the urea dosing pump 10 to constitutes a unitary assembly.

[0006] In an exemplary embodiment, the electrical resistance coil 14 is positioned within a mold. Therein, the molten plastic material of the plastic molding frame 16 is injection molded on to the electrical resistance coil 14 to completely circumscribe the electrical resistance coil 14. Once the plastic molding frame 16 completely circumscribes the electrical resistance coil 14, only the end leads 24 of the electrical resistance coil 14 are open to electrical contact from a power source and receives electric power from the power source. The electrical resistance coil 14 is supplied with electric power via the end leads 24 of the electrical resistance coil 14 to facilitate a required heat to be delivered by the electrical resistance coil 14 to the plastic molding frame 16 along a complete surface area of contact between the plastic molding frame 16 and the body of the electrical resistance coil 14 that is located between the end leads 24 of the electrical resistance coil 14. More specifically, when electric power is supplied through the end leads 24 of the electrical resistance coil 14, the electrical resistance coil 14 gets warmed up. Therein, from the electrical resistance coil 14, the heat is transferred via conduction to the plastic molding frame 16. From the plastic molding frame 16, the heat is transferred via conduction to the housing 12 of the urea dosing pump 10. In this manner, the housing 12 of the urea dosing pump 10 is warmed up uniformly as heat flows through the complete surface area of the electrical resistance coil 14. As heat flows through the complete surface area of the electrical resistance coil 14, all portions of the housing 12 of the urea dosing pump 10 that is in physical contact with the plastic molding frame 16 that houses the electrical resistance coil 14 gets warmed up, thereby thawing the urea based reducing agent that accumulates within cavities located in the housing 12 of the urea dosing pump 10. Once the urea based reducing agent that has accumulated within the housing 12 of the urea dosing pump 10 thaws completely, it may be directed towards the exhaust gas flow path of the internal combustion engine via a urea injection module (not shown).

[0007] In an exemplary embodiment, the heat generated by the electrical resistance coil 14 when electric power is supplied to end leads 24 of the electrical resistance coil 14 is allowed to permeate through the plastic molding frame 16 via the process of conduction. Therein, from the plastic molding frame 16, the heat is transmitted into the housing 12 of the urea dosing pump 10 via the process of conduction to facilitate defrosting the urea based reducing agent that is frozen within cavities located in the housing 12 of the urea dosing pump 10. In the exemplary embodiment, the electrical resistance coil 14 is wound within the plastic molding frame 16 such that the plastic molding frame 16 circumscribes a major surface area of the electrical resistance coil 14. Therein, the plastic molding frame 16 that circumscribes the major surface area of the electrical resistance coil 14 is allowed to cover a substantial portion of the housing 12 of the urea dosing pump 10 to facilitate transmitting the maximum quantity of heat from the plastic molding frame 16 to the housing 12 of the urea dosing module 10. Due to the maximum transmission of heat from the plastic molding frame 16 to the housing 12 of the urea dosing pump 10, the efficiency of heat transfer from the electrical resistance coil 14 that is wound within the plastic molding frame 16 to the housing 12 of the urea dosing pump 10 is substantially increased. Moreover, the plastic molding frame 16 that circumscribes a major surface area of the electrical resistance coil 14 covers a major portion of the surface area of the electrical resistance coil 14 to facilitate dissipating heat uniformly around the entire surface area of the plastic molding frame 16. Therein, the heat that is dissipated uniformly around the entire surface area of the plastic molding frame 16 is transmitted uniformly from the plastic molding frame 16 to the housing 12 of the urea dosing pump 10.

[0008] In an exemplary embodiment, the plastic molding frame 12 circumscribes the major surface area of the electrical resistance coil 14 such that the electrical resistance coil 14 is integrated within the plastic molding frame 16. More specifically, the electrical resistance coil 14 is integrated within the plastic molding frame 16 by injection molding the plastic molding frame 16 around the electrical resistance coil 14. Therefore, by injection molding the plastic molding frame 16 around the electrical resistance coil 14, the electrical resistance coil 14 and the plastic molding frame 16 constitutes a unitary assembly and cannot be dismantled from one another. In the exemplary embodiment, the electrical resistance coil 14 is manufactured from a material such as but not limited to Nickel, Nickel-Chromium alloy, Nickel-Copper alloy, JLC, Copper, Aluminum, and Stainless Steel but is not limited to these materials.

[0009] A working of the defrosting plate 16 that is secured within the housing 12 of the urea dosing pump 10 is described as an example. When electric power is supplied to the electrical resistance coil 14 that is integrated within the plastic molding frame 16, the electric resistance coil 14 gets warmed up. Once heated, the heat from the electrical resistance coil 14 is transmitted to the plastic molding frame 16 via the process of conduction. As the electrical resistance coil 14 is wound uniformly within the circumference of the plastic molding frame 16 to cover the maximum surface area within the plastic molding frame 16, the heat is transmitted uniformly around the complete surface area of the plastic molding frame 16 to ensure that the plastic molding frame 16 is uniformly heated by the electrical resistance coil 14. Once the plastic molding frame 16 that circumscribes the electrical resistance coil 14 is uniformly heated by the electrical resistance coil 14, the heat from the plastic molding frame 16 is uniformly transmitted to the housing 12 of the urea dosing pump 10.

[0010] As the heat is transmitted uniformly from the plastic molding frame 16 along the entire surface area of the housing 12 of the urea dosing pump 10 that is in physical contact with the plastic molding frame 16, the urea based reducing agent that had frozen within the housing 12 of the urea dosing pump 10 gets warmed up. As the frozen urea based reducing agent that is within the housing 12 of the urea dosing pump 10 gets warmed up, the frozen urea based reducing agent thaws thereby allowing the frozen urea based reducing agent to change its phase to the liquid phase. The urea based reducing agent that is in the liquid phase is allowed to flow out of the housing 12 of the urea dosing pump 10 and into the injection dosing module of the exhaust gas flow path of the engine. The urea based reducing agent is then sprayed into the exhaust gas flow path for reducing the exhaust gas that flows through the exhaust gas flow path of the engine.

[0011] It must be understood that the embodiments explained above are only illustrative and do not limit the scope of the disclosure. Many modifications in the embodiments with regard to dimensions of various components are envisaged and form a part of this invention. The scope of the invention is only limited by the scope of the claims.
, Claims:CLAIMS

We Claim

1. A urea dosing pump (10), said urea dosing pump (10) comprising:
a housing (12), said housing (12) adapted to receive a urea based reducing agent therein, wherein the urea based reducing agent freezes within said housing (12); characterized in that
an electrical resistance coil (14) integrated within a plastic molding frame (16) such that the plastic molding frame (16) circumscribes the electrical resistance coil (14), wherein said plastic molding frame (16) that circumscribes said electrical resistance coil (14) is inserted within said housing (12);
a plurality of screws (18) inserted through a plurality of bores (20) that each extend from a first end (21) of said plastic molding frame (16) to an opposite second end (23) of said plastic molding frame (16), wherein each of said plurality of screws (18) that are inserted through each of the plurality of bores (20) that extend through said plastic molding frame (16) is screwed on to each bore of a plurality of bores (26) that are defined in said housing (12) of said urea dosing pump (10); and
an outer cover (22) positioned within said housing (12), said outer cover (22) proximate to the plastic molding frame (16) and secured to said housing (12) of said urea dosing pump (10) to constitute a unitary assembly.

2. The urea dosing pump (10) in accordance with Claim 1, wherein said electrical resistance coil (14) is positioned within a mold, the molten plastic molding frame is injection molded on to the electrical resistance coil (14) to circumscribe the electrical resistance coil (14) such that only end leads (24) of the electrical resistance coil (14) are open to electrical contact from a power source.
3. The urea dosing pump (10) in accordance with Claim 2, wherein the electrical resistance coil (14) is supplied with electric power via the end leads (24) of the electrical resistance coil (14) to facilitate a required heat to be delivered by the electrical resistance coil (14) to the plastic molding frame (16) along a complete surface area of contact between the plastic molding frame (16) and the electrical resistance coil (14), and wherein the electrical resistance coil (14) is located between the end leads (24) of the electrical resistance coil (14).

4. The urea dosing pump (10) in accordance with Claim 3, wherein heat generated by the electrical resistance coil (14) when electric power is supplied to the end leads (24) of the electrical resistance coil (14) is allowed to permeate through the plastic molding frame (16) and into the housing (12) of the urea dosing pump (10) to facilitate defrosting the urea based reducing agent.

5. The urea dosing pump (10) in accordance with Claim 1, wherein the electrical resistance coil (14) is wound within the plastic molding frame (16) such that the plastic molding frame (16) that circumscribes the electrical resistance coil (14) covers a major portion of the surface area of the plastic molding frame (16) to facilitate dissipating heat uniformly around the entire surface area of the plastic molding frame (16).

6. The urea dosing pump (10) in accordance with Claim 1, wherein the electrical resistance coil (14) is integrated within the plastic molding frame (16) by injection molding the plastic molding frame (16) around the electrical resistance coil (14) such that the electrical resistance coil (14) and the plastic molding frame (16) constitutes a unitary assembly.

7. The urea dosing pump (10) in accordance with Claim 1, wherein the electrical resistance coil (14) is manufactured from a material such as but not limited to Nickel, Nickel-Chromium alloy, Nickel-Copper alloy, JLC, Copper, Aluminum, and Stainless Steel.