AIR CONTROL ELEMENT FOR AN AGRICULTURAL VEHICLE

Abstract

The invention relates to an air control element for an agricultural vehicle which has an internal combustion engine and an exhaust after-treatment device to discharge and clean the exhaust stream. The air control element cools a component of the exhaust after-treatment device.

Description

TECHNICAL FIELD

The present disclosure relates to an air control element which cools a component of an exhaust after-treatment device which discharges and after-treats the exhaust stream of an internal combustion engine.

BACKGROUND

The current legislation regarding adherence to pollutant limits in agricultural machines, which currently manifests itself in the USA as “final tier 4” and in Europe as “Stage IV,” has resulted in higher exhaust temperatures. This became necessary, since the components of the exhaust after-treatment device, which can be an oxidation catalytic converter, a particle filter, or an SCR catalytic converter, can only become effective under the condition of an increased exhaust temperature. Higher exhaust temperatures, however, simultaneously result in higher temperatures of the individual components of the exhaust after-treatment device and their surfaces. This requires protection against the increased heat radiation in areas in the immediate vicinity of components of the exhaust after-treatment device. Sensors and cables in particular are to be protected against increased heat input. In addition, however, excessively heated surfaces are to be protected against unintended access by operating personnel, in order to prevent injury in the form of burns.

Known solutions for the above-described problem use one or more Venturi nozzles in the course of the exhaust pipe or exhaust air which is produced by the fan of the engine cooling system. While the use of Venturi nozzles is done at the cost of the exhaust pressure, the use of cooling exhaust results in an additional parasitic load for the fan, since the exhaust air must be channeled in the direction of the exhaust after-treatment device and cannot be discharged into the environment with as little resistance as possible.

The object of this invention therefore consists of at least partially eliminating the described deficiencies.

SUMMARY

According to an aspect of the present disclosure, an air control element cools a component of an exhaust after-treatment device which discharges and after-treats the exhaust stream of an internal combustion engine. The air control element forms a multi-pass air control channel opposite the component.

The air control element produces a cool air flow stack effect. The process uses a freely available energy source produced by the temperature difference between the surface of the components of the exhaust after-treatment device and the ambient air. In addition to the direct insulation of the components of the exhaust after-treatment device by the air control element, the surface of the air control element is further cooled by active cooling. Finally, however, the components of the exhaust after-treatment device are not cooled, or not too strongly cooled, such that the exhaust after-treatment process could be negatively affected. In the context of this application, “multi-pass” is understood to be an arrangement which encompasses two air control channels or correspondingly two sections for air control, wherein the flow direction of the cool air can run in both channels or sections, both in the same direction as well as in opposite directions. In the case of opposite directions, the flow direction in one channel or section is opposite the exhaust flow direction and the flow direction in the other channel or section is in the direction of the exhaust flow direction.

Preferably the air control element is arranged parallel to a direction of exhaust flow. This arrangement guarantees that the air control element and the components of the exhaust after-treatment device are adjacent to each other across a section as large as possible.

The air control element preferably includes a fresh air intake opening near a downstream end of the air control element positioned downstream in relation to the direction of exhaust flow. This guarantees that fresh air is suctioned, for example, into an elevated area for an exhaust flow direction aimed vertically upward.

It is preferred that the air control element includes an outlet opening near a downstream end of the air control element in relation to the direction of exhaust flow. This guarantees that the cool air leaves the air control element after it has been indirectly heated to the maximum extent by the exhaust flow.

The air control element preferably includes two air channel sections running parallel next to each other, wherein a second air channel section is positioned inside a first air channel section. As a result there is a good thermal insulation of the component of the exhaust after-treatment device with a simultaneous cooling of the surrounding air control element.

The two control channel sections have interior open ends which are adjacent to each other so that air flows out of one channel and into the other. Preferably, these interior open ends are near a lower end of the air control element. The two control channel sections can be positioned parallel to each other.

The interior open ends are preferably positioned near an upstream end of the component. Because the intake opening and the outlet opening are positioned downstream and the interior open ends are positioned on the opposite upstream end, a maximum total length of both control channel sections can be achieved.

Preferably the air control element circumferentially surrounds the component of the exhaust after-treatment device. This guarantees an effective encapsulation of the component of the exhaust after-treatment device by the air control element.

The component of the exhaust after-treatment device preferably includes an SCR catalytic converter. This guarantees that the SCR catalytic converter is effectively encapsulated as a part of the exhaust after-treatment device, in order, on one hand, to avoid an unintentional touching by operating personnel and, on the other hand, to maintain a temperature level in the SCR catalytic converter, so that proper functioning is ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an agricultural vehicle with an exhaust after-treatment device embodying the invention; and

FIG. 2 is a sectional view along the cut line 2-2 in FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

At least one example embodiment of the subject matter of this disclosure is understood by referring to FIGS. 1 and 2 of the drawings.

Referring to FIG. 1, an agricultural work vehicle 10, such as a tractor with an operator platform or cabin 16, has a frame 14 and an internal combustion engine 12 with an exhaust after-treatment device 20 to discharge and clean the exhaust. The engine 12 is positioned as usual inside an engine compartment 18. The operator platform 16 can alternatively be designed as an open operator platform. Furthermore, parts of the exhaust after-treatment device 20 can be positioned inside the engine compartment 18, for example an oxidation catalytic converter or a particle filter.

The exhaust after-treatment device 20 includes an exhaust pipe element 24 which exits downward from the right side of the engine compartment 18. The exhaust pipe element 24 is surrounded for protection by a sheathing tube 26. The sheathing tube 26 can be in sections. A lower part of the exhaust pipe element 24 is secured to the frame 14 or to an engine-transmission unit which encompasses the internal combustion engine 12 via a holding traverse 28. The holding traverse 28 is connected with the exhaust pipe element 24 via suitable fastening means, for example clips. In the further course of the system, the exhaust after-treatment device 20 or the exhaust pipe element 24 forms a U-shaped bend, in order to extend primarily vertically along a corner post of the cabin 16 and then to discharge to the environment via a discharge opening 30. The exhaust flows in a vertically upwardly direction R.

The vertically upward running part of the exhaust after-treatment device 20 forms a first lower section 32 with a tank-shaped construction and a second upper section 34 with a pipe-shaped construction. The lower section 32 has a tank-shaped construction in order to be able to hold a component 22 of the exhaust after-treatment device 20, for example in the form of an SCR catalytic converter 36.

Referring now to FIG. 2, the SCR catalytic converter 36 has a cylindrical construction. The SCR catalytic converter 36 is circumferentially surrounded by an air control element 40 fitted to its shape, wherein the air control element 40 preferably is positioned concentric to the SCR catalytic converter 36. The air control element 40 includes a first or outer cylindrical element 42 and a second or inner cylindrical element 44. The second cylindrical element 44 is preferably positioned concentrically inside the first cylindrical element 42 and the second cylindrical element 44 surrounds, preferably concentrically, the SCR catalytic converter 36. As a result of this arrangement, the air control element 40 forms a multi-pass air control channel 46 which surrounds the SCR catalytic converter 36. A first air control channel 48 is thereby formed between the first and the second cylindrical element 42, 44 and a second air control channel 50 is formed between the second cylindrical element 44 and the SCR catalytic converter 36.

The first air control channel 48 includes an intake opening 56 for fresh air positioned near a downstream end area 52 of the air control element 40 in relation to the exhaust flow direction. The intake opening 56 is designed as a louver constructed along the circumference of the first cylindrical element 42. Ambient air or cool air is supplied via the intake opening 56 to the first channel 48. The ends of two control channels 48, 50 near the upstream end of the component 22 are open to each other and to an overflow chamber 58. Air flows though channel 48, overflow chamber 58 and into channel 50. The second control channel 50 includes an outlet opening 60 positioned near a downstream end 52 of the air control element 40 in relation to the exhaust flow direction. The cool air from the air control element 40 flows through the outlet opening 60 and through an intermediate area 62 between the exhaust pipe element 24 and the sheathing tube 26.

The air control element 40 interacts with and cools the encased SCR catalytic converter 36. As a result of the surface of the SCR catalytic converter being heated by the operation of the internal combustion engine 12, the air located in the second control channel section 50 is heated and rises in the direction of the outlet opening 60. Because of the resulting suction effect, cool air is drawn in through the intake opening 52 the first air channel 48 and the overflow chamber 58. This air circulation cools the SCR catalytic converter 36.

LIST OF REFERENCE CHARACTERS

• 10 Work vehicle
• 12 Internal combustion engine
• 14 Frame
• 16 Operator platform
• 18 Engine compartment
• 20 Exhaust after-treatment device
• 22 Component
• 24 Exhaust pipe element
• 26 Sheathing tube
• 28 Holding traverse
• 30 Discharge opening
• 32 Lower section
• 34 Upper section
• 38 SCR catalytic converter
• 40 Air control element
• 42 Cylindrical element
• 44 Cylindrical element
• 46 Air control channel
• 48 Control channel section
• 50 Control channel section
• 52 End area
• 54 End area
• 56 Intake opening
• 58 Overflow chamber
• 60 Outlet opening

While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. It will be noted that alternative embodiments of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the present invention as defined by the appended claims.

Claims

1. An air control element for an agricultural work vehicle having an internal combustion engine, an exhaust after-treatment device to discharge and after-treat an exhaust stream from the internal combustion engine, a component of the exhaust after-treatment device being cooled by the air control element, wherein the air control element comprises:

a multi-pass air control channel adjacent the component.

2. The air control element of claim 1, wherein:

the air control element is arranged parallel to an exhaust flow direction.

3. The air control element of claim 1, wherein:

the air control element includes an intake opening for cool air near a downstream end of the component in relation to the exhaust flow direction.

4. The air control element of claim 1, wherein:

the air control element includes an outlet opening near a downstream end of the air control element in relation to the exhaust flow direction.

5. The air control element of claim 1, wherein:

the air control channel includes a first control channel and a second control channel positioned inside the first control channel.

6. The air control element of claim 5, wherein:

an overflow chamber is formed near an end of the component; and

the first control channel has an open end which communicates with an open end of the second control channel via the overflow chamber.

7. The air control element of claim 6, wherein:

the overflow chamber and the open ends are positioned near an upstream end of the component.

8. The air control element of claim 1, wherein:

the air control element circumferentially surrounds the component.

9. The air control element of claim 1, wherein:

the component comprises an SCR catalytic converter.