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] The present disclosure relates to a heat sink for a fuel injector provided in an exhaust gas channel.

Background of the invention
[0002] Internal combustion engines are widely used in transportation sector. The combustion of fossil fuels in internal combustion engines leads formation of unburned hydrocarbons and soot particles along with other toxic and greenhouse gases.
[0003] The emission standard requirements in different jurisdictions requires that the combustion gases produced in internal combustion engine be filtered for particulate matter and that toxic gases in the exhaust be removed.
[0004] Diesel particulate filters are introduced in the exhaust channel of automobiles to filter the exhaust gas for unburned hydrocarbons and soot particles.
[0005] But overtime the particulate matter accumulates in the diesel particulate filter which needs to be removed. Diesel particulate filter regeneration methods are employed to remove the accumulated particulate matter from the filter.
[0006] Diesel particulate filter regeneration can be done either passively or actively. Passive diesel particulate filter regeneration involves the use of the heat of the exhaust gases itself to burn-off the accumulated particulate matter from the diesel particulate filter. In active diesel particulate filter regeneration, a high amount of heat is actively introduced in the exhaust channel to burn-off the accumulated particulate matter. Active diesel particulate filter regeneration is carried out by injecting small doses of the fuel into the exhaust channel.
[0007] An injection module is used in the active diesel particulate filter regeneration to introduce the fuel in the exhaust channel. A fuel injector in the injection module is activated by the engine control unit to introduce the fuel into the exhaust channel.
[0008] Since the high temperature is involved in the active diesel particulate filter regeneration a dedicated cooling system is necessary for the injection module.
[0009] One technical problem in such a system is that during hot shutdown of the engine the coolant pump in the cooling system of the injection module also shuts down but the high temperature in the exhaust channel remains. The high temperature in the exhaust channel when the coolant circuit is shutdown may lead to heat damage of the fuel injector in the injection module.
[0010] Efforts have been made in the related prior art to provide different solutions for preventing the heat damage of the injection module in an active diesel particulate filter regeneration. For example, a Chinese patent no. CN104675487A provides a method for preventing heat injury of an injection module, a controller, and a urea exhaust purification system. The method for preventing heat injury of the injection module may include: (a) calculating the cooling amount of cooling water required by preventing heat injury of the injection module that ejects a reductant, (b) calculating the cooling amount of cooling water of an engine which changes according to operation of a clutch water pump, (c) checking the operating state of the clutch water pump by comparing the required cooling amount of cooling water with the cooling amount of cooling water of the engine, and (d) when the clutch water pump is operated under the condition that the required cooling amount of cooling water is larger than the cooling amount of cooling water of the engine, switching the clutch water pump to closure to stop operation thereof. However, the invention in the prior art will not be able to prevent the heat damage of the injection module and the fuel injector when the coolant pump is shutdown.
[0011] Therefore, the present disclosure overcomes the above-mentioned problem associated with the traditionally available method or system.

Brief description of the accompanying drawing
[0012] An embodiment of the disclosure is described with reference to the following accompanying drawings:
[0013] Fig. 1 illustrates the layout of an active diesel particulate filter regeneration system; and
[0014] Fig. 2 illustrates a cross-sectional view of the injection module in an active diesel particulate filter regeneration system.

Detailed description of the embodiments
[0015] In an embodiment of the present disclosure, Fig. 1 illustrates the layout of an active diesel particulate filter (103) regeneration system and Fig. 2 illustrates a cross-sectional view of the injection module (102) in an active diesel particulate filter (103) regeneration system.
[0016] In an embodiment of the present disclosure, the invention involves a heat sink for a fuel injector (202) provided in an exhaust gas channel upstream of a diesel particulate filter (103), wherein the heat sink comprising a fuel injector cavity (201) for accommodating the fuel injector (202), an inlet (207) for coolant, an outlet (208) for coolant, an internal cooling channel (205) connecting the inlet (207) and the outlet (208) characterized in that at least one additional cooling channel (206) in said heat sink (203), surrounding the fuel injector cavity (201); and a plurality of connecting bores (204) connecting the internal cooling channel (205) to the additional cooling channel (206).
[0017] In an aspect of the invention one of the plurality of connecting bores (204) connecting the internal cooling channel (205) to one end of the additional cooling channel (206) and another one of the plurality of connecting bores (204) connecting the internal cooling channel (205) to the other end of the additional cooling channel (206).
[0018] In another aspect of the invention the additional cooling channel (206) having a helical construction.
[0019] In yet another aspect of the invention the additional cooling channel (206) having a rectangular cross-section.
[0020] In yet another aspect of the invention the additional cooling channel (206) having a circular cross-section.
[0021] The present invention is implemented to solve the problem of heat damage to a fuel injector (202) in an injection module (102) which is part of an active diesel particulate filter (103) regeneration system when the engine is in hot shutdown condition.
[0022] When the engine shuts down coolant pump which circulates coolant through the internal channel of the injection module (102) also shuts down. In such a situation a dead volume of coolant will remain in the internal cooling channel (205). This dead volume of coolant will have to absorb the heat from the fuel injector (202) during engine shutdown condition.
[0023] But in active diesel particulate filter (103) regeneration process high temperatures of the range 600oC are generated in the exhaust channel (101). This high temperature in the exhaust channel (101) will transferred as heat to the fuel injector (202) of the injection module (102) even when the engine and coolant pump is shutdown. The limited dead volume of the coolant in the internal cooling channel (205) will not be sufficient to take away the heat from the fuel injector (202). Thus, the fuel injector (202) may get heat damaged.
[0024] The present invention solves this problem by ensuring that more volume of coolant remains in the injection module (102) as dead volume when the engine is shutdown. The increased dead volume of coolant can take away more heat from the fuel injector (202) and protect the fuel injector (202) from heat damage.
[0025] The dead volume of coolant is increased in the present invention using additional cooling channels (206) surrounding the fuel injector (202) in the injection module (102). The additional cooling channels (206) are provided in the heat sink of the injection module (102).
[0026] The heat sink in an embodiment of the invention is made from aluminum using an additive manufacturing process.
[0027] The heat sink in an embodiment of the invention as represented by fig. 2 has an inlet (207) for the coolant to enter the internal cooling channel (205). The internal cooling channel (205) is a hollow path for the coolant within the heat sink. The coolant entering the heat sink through the inlet (207) will circulate through the internal cooling channel (205) and moves out of the heat sink through the outlet (208). The connecting bores (204) allows some quantity of the coolant to move from the internal cooling channel (205) to the additional cooling channel (206). The connecting bores (204) may be of circular, rectangular or some other suitable cross-section and will be in the form of a hollow path for the coolant to flow. By connecting the internal cooling channel (205) and additional cooling channel (206) using connecting bores (204) some quantity of the coolant will move to the additional cooling channel (206) from the internal cooling channel (205) through the connecting bores (204). The pressurized coolant flow using a coolant pump ensures that the coolant moves into and fills the additional cooling channel (206) also.
[0028] In an embodiment of the invention the additional cooling channel (206) is in the form of a hollow helical path within the heat sink surrounding the fuel injector cavity (201). The length and pitch of the helical path can be fixed according to the dimensions of the heat sink. The cross-section of the helical path can be circular, rectangular or any other favorable shape.
[0029] In another embodiment of the invention the additional cooling channel (206) is having a circular area of cross-section.
[0030] In yet another embodiment of the invention the additional cooling channel (206) is having a rectangular area of cross-section.
[0031] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions, or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.
, Claims:We Claim:
1. A heat sink for a fuel injector provided in an exhaust gas channel upstream of a diesel particulate filter, wherein the heat sink comprising:
- a fuel injector cavity (201) for accommodating the fuel injector (202);
- an inlet (207) for coolant;
- an outlet (208) for coolant;
- an internal cooling channel (205) connecting the inlet (207) and the outlet (208);
characterized in that:
- at least one additional cooling channel (206) in said heat sink (203), surrounding the fuel injector cavity (201); and
- a plurality of connecting bores (204) connecting the internal cooling channel (205) to the additional cooling channel (206).
2. The heat sink as claimed in claim 1, wherein one of the plurality of connecting bores (204) connecting the internal cooling channel (205) to one end of the additional cooling channel (206) and another one of the plurality of connecting bores (204) connecting the internal cooling channel (205) to the other end of the additional cooling channel (206).
3. The heat sink as claimed in claim 1, wherein the additional cooling channel (206) having a helical construction.
4. The heat sink as claimed in claim 1, wherein the additional cooling channel (206) having a rectangular cross-section.
5. The heat sink as claimed in claim 1, wherein the additional cooling channel (206) having a circular cross-section.