COOLING DEF DOSER

Abstract

An apparatus for cooling a DEF doser tip in an engine having an exhaust pipe comprises a cooling block connected with the DEF doser tip. A first port is connected with the cooling block. One end of a cooling conduit connected to the first port. An opposite end of the cooling conduit connected to a first end of a second tube. An opposite end of the second tube connected with a source of engine coolant. A second port is connected with the cooling block. An end of the second port opposite to the cooling block is connected with the source of engine coolant. Means for maintaining configuration of the cooling conduit are disposed between the cooling conduit and the exhaust pipe.

Description

BACKGROUND

This application generally relates to an apparatus and a method for cooling a diesel exhaust fluid (hereinafter “DEF”) doser. More specifically, this application relates to an apparatus and a method for cooling a DEF doser in a combustion, either compression combustion or spark ignition combustion, engine. For the sake of clarity, embodiments described in this application will be limited to a compression combustion engine, although those same embodiments may be used, with suitable modification, in a spark ignition combustion engine.

In some compression combustion engines, such as those that have a selective catalytic reduction (SCR) exhaust management system, like those available from Cummins Emission Solutions of Columbus, Indiana, use a DEF doser with a tip. The tip may have a temperature requirement that should not be exceeded. An exemplary DEF doser tip is in the Denoxtronic® doser available from Robert Bosch GmbH of Stuttgart, Germany. This particular DEF doser tip has a temperature requirement of 120 degrees Celsius. In some applications of a DEF doser, compliance with the DEF doser tip temperature requirement is achieved by flowing engine coolant through the DEF doser while the engine is running However, when the engine is turned off, flow of engine coolant ceases. Temperature of the engine coolant remaining in the DEF doser after the engine is turned off can continue to increase. Because the engine coolant remains essentially stagnant within the DEF doser, the temperature requirement of the DEF doser tip may be exceeded. Exceeding the temperature requirement of the DEF doser tip can lead to damage and to necessary repair of the DEF doser and the associated engine.

It is recognized that a DEF doser tip operates in a harsh environment. For example, U.S. Pat. No. 8,347,605 states that some DEF doser tips use water cooling systems. “However, water cooling requires specialized plumbing and additional components that ultimately increase costs and reduce reliability. '605 patent, column 2, lines 19-23.

It is desirable to provide an improved method and an apparatus for cooling a DEF doser tip.

SUMMARY

A number of embodiments of a method and apparatus for cooling a DEF doser tip are provided. According to one embodiment, an apparatus for cooling a DEF doser tip in an engine having an exhaust pipe comprises a cooling block connected with the DEF doser tip. A first port is connected with the cooling block. One end of a cooling conduit connected to the first port. An opposite end of the cooling conduit connected to a first end of a second tube. An opposite end of the second tube connected with a source of engine coolant. A second port is connected with the cooling block. An end of the second port opposite to the cooling block is connected with the source of engine coolant. Means for maintaining configuration of the cooling conduit are disposed between the cooling conduit and the exhaust pipe.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a DEF doser having one embodiment of an apparatus for cooling a DEF doser tip;

FIG. 2 is a perspective view of a portion of the embodiment of FIG. 1;

FIG. 3 is an elevational view of the embodiment of FIG. 1;

FIG. 4 is an elevational view of the embodiment of FIG. 1 showing dimensions;

FIG. 5 is a view similar to FIG. 4 showing dimensions;

FIGS. 6A and 6B are perspective views of a DEF doser having another embodiment of an apparatus for cooling a DEF doser tip;

FIG. 7 is an elevational view of a portion of the embodiment of FIG. 6 showing dimensions;

FIG. 8 is another elevational view of the portion of the embodiment of FIG. 7 showing dimensions;

FIG. 9 is a perspective view of the portion of the embodiment of FIG. 8;

FIG. 10 is a perspective view of another portion of the embodiment of FIG. 6;

FIG. 11 is another perspective view of the portion of the embodiment of FIG. 10;

FIG. 12 is a top elevational view of a further portion of the embodiment of FIG. 6 showing dimensions;

FIG. 13 is a side elevational view of the portion of the portion of the embodiment of FIG. 12 showing dimensions;

FIG. 14 is a perspective view of the portion of the portion of the embodiment of

FIG. 13; and

FIGS. 15A and 15B are perspective views of a DEF doser having an additional embodiment of an apparatus for cooling a DEF doser tip.

DETAILED DESCRIPTION

Disclosed herein are multiple embodiments of an apparatus and a method for cooling a DEF doser tip. As the following makes apparent, these embodiments do not require any specialized plumbing or other costly components. The embodiments discussed below provide an improved method and apparatus for cooling a DEF doser tip that improve on other currently available methods and apparatus for cooling a DEF doser tip.

FIG. 1 shows a perspective view of one embodiment of a DEF doser tip cooling apparatus 10 attached to an exhaust pipe 11. For the sake of clarity of understanding, this embodiment will be discussed with respect to its implementation with an after treatment system currently provided by Cummins Emissions Solutions of Columbus, Indiana. That after treatment system uses a DEF doser like the Denoxtronic® doser available from Robert Bosch GmbH of Stuttgart, Germany. Of course, the embodiments discussed herein may be used, with suitable modifications with any appropriate after treatment system using any appropriate DEF doser.

The DEF doser tip cooling apparatus 10 comprises a cooling conduit 12 that extends fluidly from a source 14 of engine coolant. A first port 16 is disposed at one end of the cooling conduit 12. In the illustrated embodiment, the first port 16 is a J2044 connector available from VOSS Automotive GmbH of Wipperfürth, Germany. Other embodiments may use different constructions of the first port 16. The first port 16 fluidly joins a cooling block 18 for a DEF doser 20 with a first tube 22. In one embodiment, the first tube 22 is made of a suitable polymer, such as EPDM and the like. An end of the first tube 22 opposite to the end thereof connected to the first port 16 is connected with a coolant loop 24. The coolant loop 24 is made of a suitable material, such as stainless steel and the like. An end of the coolant loop 24 opposite to an end thereof connected to the first tube 22 is connected to a second tube 26. In the illustrated embodiment, the second tube 26 is made of a suitable polymer, such as EPDM and the like. An end of the second tube 26 opposite to the end thereof connected to the coolant loop 24 is connected to a second port 28 on the source 14 of engine coolant. A third port 30 on the cooling block 18 is connected with a fourth port 32 on the source 14 of engine coolant thereby forming a fluid circuit from the source 14 of engine coolant, through the second tube 26, through the coolant loop 24, through the first tube 22, through the first port 16, through the cooling block 18, through the third port 30 and the fourth port 32 to the source 14 of engine coolant.

In an exemplary embodiment, the coolant loop 24 extends about 37 inches from the first tube 22 to the second tube 26, has an outer diameter of about 5 inches and a wall thickness of about 0.5 inches. Further details of one embodiment of the coolant tube 24 shown in FIGS. 4 and 5 are specified in the following table.

		X	Y	Z	R
	P0	0.0	0.0	0.0
	P1	70.0	0.0	0.0	20.0
	P2	50.9	118.5	0.0	20.0
	P3	51.6	118.6	−45.0	20.0
	P4	78.2	32.7	−32.3	20.0
	P5	0.3	14.4	−26.8	20.0
	P6	−27.2	8.0	1.5	20.0
	P7	−37.0	5.7	1.5
	indicates data missing or illegible when filed

To maintain configuration of the cooling conduit 12, a support bar 34 is provided. The support bar 34 supplies rigidity to the cooling conduit 12 so that movement of the cooling conduit 12 is reduced during operation of an associated engine and vehicle. In one embodiment, a first end 36 of the support bar 34 is fixed to a portion of a housing 40 adjacent the DEF doser 20 by suitable means, such as a fastener or the like. In some applications, the first end 36 is fixed to a bore 42 pre-existing on an exhaust management system provided by Cummins Emission Solutions of Columbus, Indiana. A second end 38 of the support bar 34 is joined to an outer surface of the exhaust pipe 11 and/or a portion of the cooling conduit 12. The support bar 34 is joined to the cooling conduit 12 at multiple locations. In the illustrated embodiment, the support bar 34 is joined to the cooling conduit 12 at two spaced-apart locations indicated by A and B in the Figures. Joints between the cooing conduit 12 and the support bar 34 may be formed by any suitable means, such as brazing and the like.

FIGS. 6A and 6B show another embodiment of DEF doser tip cooling apparatus 10′. The DEF doser tip cooling apparatus 10′ is substantially similar to the DEF doser tip cooling apparatus 10 shown in FIG. 1, hence the like reference numerals for similar elements, except for the differences noted here. Unlike the DEF doser tip cooling apparatus 10, the DEF doser tip cooling apparatus 10′ does not include a linear first tube 22 as shown in FIGS. 1 and 4. In the DEF doser tip cooling apparatus 10′, the first tube 22 is curved.

The coolant loop 24 of the DEF doser tip cooling apparatus 10′ has tapered section 44, shown clearly in FIGS. 7 through 9, on an end of the coolant loop 24 opposite to the second tube 26. Some exemplary dimensions of the structures shown in FIGS. 7 through 9 are summarized below.

		X	Y	Z	R
	P0	0.0	0.0	0.0
	P1	99.4	0.0	0.0	20.0
	P2	88.5	−0.8	−45.0	20.0
	P3	−0.5	−13.3	−32.3	20.0
	P4	−6.2	66.5	−28.8	20.0
	P5	−9.2	94.7	1.5	20.0
	P6	−11.7	144.6	1.5
	DISTANCE FROM P0 TO P6 =	145.1
	APPROX CTRLINE LENGTH =	362.8
	TUBING OD =	12.825
	WALL THICKNESS =	1.850
	indicates data missing or illegible when filed

The tapered section 44 is joined with a pipe 46 that extends from the tapered section 44 to the first tube 22. The pipe 46 can be formed from any suitable material, such as a polymer and the like. Use of the pipe 46 facilitates assembly of the DEF doser tip cooling apparatus 10′. For clarity, the pipe 46 is shown in dotted lines in FIGS. 6A, ̂b, 15A and 15B. The pipe 46 is shown clearly in FIGS. 12 through 14. Exemplary dimensions of the pipe 46 shown in those Figures are summarized below.

		X	Y	Z	R
	P0	0.0	0.0	0.0
	P1	59.5	0.0	0.0	20.0
	P2	48.0	0.0	71.4
	DISTANCE FROM P0 TO P2 =	86.1
	APPROX CTRLINE LENGTH =	119.5
	TUBING IO =	9.525
	indicates data missing or illegible when filed

FIGS. 15A and 15B show a further embodiment of DEF doser tip cooling apparatus 10″. The DEF doser tip cooling apparatus 10″ is substantially similar to the DEF doser tip cooling apparatus 10′ shown in FIGS. 6A and 6B, hence the like reference numerals for similar elements, except for the differences noted here. Unlike the DEF doser tip cooling apparatus 10′, the DEF doser tip cooling apparatus 10″ does not include a support bar 34. Instead, the DEF doser tip cooling apparatus 10″ uses a support clip 48 shown in FIGS. 15A, 15B and 16 to maintain configuration of the cooling conduit 12 by joining the cooling conduit 12 with the exhaust pipe.

The support clip 48 cooperates with a strap 50 and fittings 52A and 52B to maintain configuration of the DEF doser tip cooling apparatus 10″. The strap 50 is formed of suitable materials, such as a metal and the like, and is attached to (circumferentially surrounds an outer surface of the exhaust pipe 11 in the illustrated embodiment) the exhaust pipe 11. In the illustrated embodiment, the strap 50 includes a pair of matching bores 54A and 54B. The support clip 48 includes a bore 56 intended to be aligned with the bores 54A and 54B on the strap 50. When suitably assembled, a suitable fastener, such as a bolt and the like, (not shown for clarity) can be inserted through the bores 54A, 54B and 56 to join the support clamp 48 with the strap 50 and to join the strap 50 with the exhaust pipe 11. The fittings 52A and 52B couple on one side to the cooling conduit 12 and to the support clip 48 on the other side.

Opposite to the bore 56, the support clip 48 includes opposing fingers 58A and 58B shown in FIGS. 15A, 15B and 16. The fingers 58A and 58B include apertures 60A and 60B. The apertures 60A and 60B mate with corresponding apertures on the fittings 52A and 52B. Appropriate fasteners, such as bolts and the like, are inserted through the apertures on the fittings 52A and 52B and the apertures 60A and 60B on the support clip 48 to join the cooling conduit 12 with the support clip 48 and thus with the exhaust pipe 11.

Considering the various embodiments of the DEF doser tip cooling apparatus 10, 10′ and 10″, it can be appreciated that both the support bar 34 and the support clip 48 together with the strap 50 and the fittings 52A and 52B comprise means for maintaining configuration of the cooling conduit 12 disposed between the cooling conduit 12 and the exhaust pipe 11. Other constructions can be used to realize the means for maintaining configuration of the cooling conduit 12. These other constructions may be chosen to meet certain needs, such as space limitations, fuel economy, weight, heat, vibration resistance, etc.

With structure of various embodiments of the DEF doser tip cooling apparatus being thusly described, operation of the DEF doser tip cooling apparatus will now be discussed. To facilitate understanding, operation of the DEF doser tip cooling apparatus will be discussed using the embodiment of the DEF doser tip cooling apparatus 10 shown in FIGS. 1 through 5. However, the following discussion of operation of the DEF doser tip cooling apparatus applies equally to all embodiments of the DEF doser tip cooling apparatus disclosed herein. It is to be noted that further specifications of the DEF doser tip cooling apparatus may become apparent in the following discussion. While operation of the DEF doser tip cooling apparatus is described in a particular order, it is possible that steps of the operation detailed below may be performed in any suitable order and with any appropriately desired modifications.

When an engine associated with the DEF doser tip cooling apparatus 10 is operating, under the influence of a water pump, coolant flows from the source 14 of engine coolant through the cooling conduit 12 thereby maintaining the DEF doser tip in compliance with its temperature requirement. When the engine is shut off, the water pump stops operating. Coolant no longer flows through the cooling conduit 12 under the influence of the water pump. Because the water pump no longer provides circulating engine coolant, the doser tip can exceed its thermal requirement causing damage.

However, the DEF doser tip cooling apparatus 10 provides movement of engine coolant through the cooling block 18 even though the engine and the associated water pump are no longer operating. There is engine coolant present at the first port 16 and there is engine coolant present at the third port 30. Temperature of the engine coolant present at the first port 16 differs from the temperature of the engine coolant present at the third port 30. This temperature differential drives movement of engine coolant irrespective of lack of operation of the water pump. Dimensions of the apparatus 10 are chosen so that there is always at least about 16 cubic centimeter volume of engine coolant on each side (one side being adjacent the first port 16 and another side being adjacent the third port 30) of the DEF doser 20. In this manner, the likelihood that the DEF doser tip exceeds its thermal requirement after engine shut down is reduced.

REFERENCE CHARACTER  ELEMENT
10                   DEF doser tip cooling apparatus
10′ (FIGS. 6A, 6B)   DEF doser tip cooling apparatus
10″ (FIGS. 15A, 15B) DEF doser tip cooling apparatus
11                   Exhaust pipe
12                   Cooling conduit
14                   Source of engine coolant
16                   First port
18                   Cooling block
20                   DEF doser
22                   First tube
24                   Coolant loop
26                   Second tube
28                   Second port
30                   Third port
32                   Fourth port
34                   Support bar
36                   First end (of 34)
38                   Second end (of 34)
40                   Housing
42                   Bore (on 40)
44                   Tapered section
46                   Pipe
48                   Support clip
50                   Strap
52A, 52B             Fittings
54A, 54B             Bore (on 50)
56                   Bore (on 48 for 54)
58A, 58B             Fingers (on 48)
60A, 60B             Aperture (on 58A, 58B)

Claims

1. An apparatus for cooling a DEF doser tip in an engine having a selective catalytic reduction system and an exhaust pipe, the apparatus for cooling the DEF doser tip comprising:

a cooling block connected with the DEF doser tip;

a first port connected with the cooling block;

a cooling conduit;

one end of the cooling conduit connected to the first port;

an opposite end of the cooling conduit connected to a first end of a second tube;

an opposite end of the second tube connected with a source of engine coolant;

a second port connected with the cooling block;

an end of the second port opposite to the cooling block connected with the source of engine coolant; and

means for maintaining configuration of the cooling conduit disposed between the cooling conduit and the exhaust pipe.

2. The apparatus as defined in claim 1 wherein the means for maintaining configuration of the cooling conduit comprises a support bar fixed to the cooling conduit and to a housing adjacent the DEF doser tip for supplying rigidity to the cooling conduit.

3. The apparatus as defined in claim 2 wherein the support bar is fixed to the cooling conduit at two spaced-apart locations.

4. The apparatus as defined in claim 2 wherein the support bar is fixed to the housing at a pre-existing bore on the housing.

5. The apparatus as defined in claim 2 wherein an end of the support bar is fixed to the exhaust pipe.

6. The apparatus as defined in claim 1 wherein the means for maintaining configuration of the cooling conduit comprises a support clip joining the exhaust pipe with the cooling conduit.

7. The apparatus as defined in claim 6 further comprising:

a strap joining the exhaust pipe with the support clip.