Patent ID: 12241397

DETAILED DESCRIPTION

The drawings are provided by way of reference only, and will be acknowledged as not to scale.

With reference toFIG.1, an engine exhaust gas treatment system10is shown. The engine exhaust gas treatment system10has a urea solution supply tank11which supplies urea to a urea supply module12. The urea supply module12next supplies a urea dosing module13via the urea feed lines14a,14band urea return lines15a,15b(indicated by arrows F—feed and R—return respectively). An alternative construction of the exhaust gas treatment system10including an exhaust silencer21sis shown in dotted lines and can be better seen inFIG.10.

In some embodiments and configurations, the urea return line15bmay not be required.

Dosing module13injects the urea into a Selective Catalytic Reduction (SCR) catalytic converter21which is longitudinally aligned along an axis C, which is substantially vertical, in the general direction of the exhaust gas stream indicated by arrow G out of an exhaust pipe21a. The SCR and exhaust pipe21aare aligned to have the gas flow passing therethrough substantially aligned with the axis C, the axis C being substantially perpendicular to the ground.

The vehicle has an engine cooling system30comprising a heat exchanger31, a fan32, and an engine coolant pump33to supply cooling fluid, further referred to as coolant, to various components of the tractor.

The engine cooling system30may comprise further components such as sensors, valves, etc., to control the engine cooling system30.

The coolant is provided to the urea dosing module13via a coolant feed line branch40(in a direction indicated by arrow40a) which is connected to a coolant feed port13aof the urea dosing module13.

The coolant is returned to the heat exchanger31via a coolant return line branch50(in a direction indicated by arrow50a) which is connected to a coolant return port13bof the urea dosing module13.

In normal operation, the engine coolant pump33is constantly circulating the coolant through coolant line branches40,50so that the urea dosing module13is protected from overheating.

Upon shut down of the engine, the circulation of coolant stops and remaining coolant in the urea dosing module13may start to heat up excessively and may be consequently damaged.

With reference toFIG.2, the coolant feed line branch40, seen in coolant flow direction indicated with arrow40a, is provided with a first feed pipe section41extending vertically upwards above the horizontal level H of the ports13aand13bof the dosing module13.

A second feed pipe section42, is U-shaped or siphon-shaped with the ends directed downwards, i.e., towards the ports13aand13bof the dosing module13.

One end of the second feed pipe section42is connected to and follows on from the first feed pipe section41and the second end and is connected to a vertical third feed pipe section43which ends at port13a.

The coolant return line branch50contains coolant that flows in the opposite direction to that of the coolant in the coolant feed line branch40, and flows in a direction indicated by arrow50a. The coolant return line branch50has a first return pipe section51extending vertically upwards above the horizontal level H of the ports13aand13bof the dosing module13.

A second return pipe section52, is U-shaped or siphon-shaped with the ends directed downwards, i.e. towards the ports13aand13bof the dosing module13.

One end of the second return pipe section52is connected to and follows on from the first return pipe section51and the second end and is connected to a vertical third return pipe section53which ends at port13b.

During normal operation, coolant coming from engine coolant pump33passes first feed pipe section41upwards and is directed downwards by U-shaped second feed pipe section42into a vertical third feed pipe section43to enter the dosing module13via at port13a.

The coolant then exits the dosing module13via port13band flows upwards in third return pipe section53to be directed downwards by U-shaped second return pipe section52and then passes through first return pipe section51.

Upon shut down of the engine, with the engine coolant pump33not operating, the coolant in third feed pipe section43and third return pipe section53is trapped due to siphon action in the design.

Remaining coolant in the dosing module13is further heated up and starts to evaporate.

The evaporation of the coolant in the pipes causes evaporation bubbles to ascend in either the third feed pipe section43or the third return pipe section53, depending on the inclination of the vehicle.

If the vehicle stands inclined in a direction indicated with Arrow A such that axis A′ is substantially vertical, port13aof the dosing module13is at a higher level compared to port13b.

Because of this, evaporation bubbles will ascend into third feed pipe section43and displace the remaining coolant into first feed pipe section51, whereas in the third return pipe section53, no evaporation bubbles occur.

If the vehicle stands inclined in the opposite direction indicated with Arrow B such that axis B′ is substantially vertical, port13bof dosing module13is at a higher level compared to port13a.

Because of this, evaporation bubbles will ascend into the third return pipe section53and displace the remaining coolant into the first return pipe section51, whereas in the third feed pipe section43, no evaporation bubbles occur.

In an example embodiment, the third feed pipe section43and/or the third return pipe section53extends in a substantially vertical direction from the ports13a,13band forms a reservoir in which coolant is trapped after engine shut down.

Because evaporation bubbles reduce the density of the fluid in the respective pipe sections, the trapped fluid in the other section flows into the dosing module13to provide extra coolant for keeping the acceptable temperature level.

Because only a small inclination of the vehicle is enough to cause the evaporation through one of ports13aand13b, only one of the third feed pipe section43or the third return pipe section53may face evaporation bubbles while the other third feed pipe section43or third return pipe section53can provide extra coolant.

Even if both ports13aand13bare at an exact horizontal level, the evaporation bubbles will ascend in only one of third feed pipe section43or third return pipe section53.

In some installations, it is enough to provide the third feed pipe section43or third return pipe section53with the same inner diameter as the other sections of the feed line branch40or return line branch50to form a reservoir sufficient to provide extra coolant.

In further embodiments, the third feed pipe section43or third return pipe section53may have a diameter expansion44,54(e.g., in the form of a rubber hose inserted on a pipe on both ends, seeFIGS.2,9, and10). Thereby the volume of coolant trapped can be increased or expanded as required.

With reference toFIG.3, an example is shown wherein the dosing module13is provided with ports13aand13bnot aligned horizontally. As port13bis on a higher level H1while port13ais on a lower level H2, the port13bwould always be above port13aat every possible/allowable inclination of the vehicle.

This ensures that evaporation always takes place through port13b. As a consequence, only the third feed pipe section43and expansion44is necessary to provide extra coolant for the case of engine shut-off.

In some embodiments, a bypass line60is provided between the third feed pipe section43and the third return pipe section53.

In some circumstance, the evaporation of coolant may result in an excessive high pressure trapped in pipe section43,53. This high pressure would prevent coolant from the other pipe section to flow into the dosing module. The bypass line60serves to balance the pressure in pipe section43and53so that coolant can freely flow.

FIGS.4and5show the components of the cooling system installed on a tractor (not shown).

The first feed pipe section41and second feed pipe section42are integrated in one steel pipe46. Similarly, first return pipe section51and second return pipe section52are integrated in one steel pipe56.

The third feed pipe section43and the third return pipe section53are constructed from rubber hoses having a relative large diameter compared to the other pipe section to which they are attached and thus form diameter expansion44,54.

InFIG.4, the third feed pipe section43and third return pipe section53are shown in dotted lines to show the compact installation by placing the lines in close vicinity and one behind the other to reduce necessary installation space.

FIG.6shows a Selective Catalytic Reduction (SCR) catalytic converter21and dosing module13both installed in a vertical direction along axis C and suitable for installation at the right A-pillar of a cab of a tractor (not shown) similar to the installation described in International Patent Application Publication WO 2010/069806 A1, “Exhaust Systems for Vehicles,” published Dec. 7, 2009. The components of the feed line branch40and coolant return line branch50are supported by a sheet metal support70suitable for attachment to the A-pillar of an associated tractor.

As shown withFIG.7, representing a sectional view ofFIG.6at a plane X perpendicular to axis C, the sheet metal support70is situated in-between the Selective Catalytic Reduction (SCR) catalytic converter21and the third feed pipe section43along with diameter expansion44, and third return pipe section53, along with diameter expansion54, and thereby provides a thermal or heat shield.

Because of this arrangement, the coolant trapped in the third feed pipe section43, along with diameter expansion44, and the third return pipe section53, along with diameter expansion54is kept at a relatively lower temperature, than if there were no heat shield, to provide more cooling capacity for the dosing module13.

Additionally, this enables the third feed pipe section43, along with diameter expansion44, and the third return pipe section53, along with diameter expansion54, to be made of rubber (hoses) or other material with low thermal resistance, because they are protected by the thermal shielding.

The first feed pipe section41and first return pipe section51are positioned in between sheet metal support70and catalytic converter21because the heat impact is of minor relevance when steel pipes are used.

With reference toFIG.8, the Selective Catalytic Reduction (SCR) catalytic converter21, the dosing module13, and major parts of the components are hidden by covers80,81to prohibit an operator from contacting the hot parts.

In an alternative embodiment as best seen inFIG.10, an exhaust gas treatment10′ is shown.

Dosing module13injects the urea into a Selective Catalytic Reduction (SCR) catalytic converter21′ aligned perpendicular to the axis C′ and axis C, which are substantially vertical. The exhaust pipe21a′ and an exhaust silencer21sare aligned with the axis C′ and in the general direction of the exhaust gas stream indicated by arrow G′ out of an exhaust pipe21a′. The SCR21′ is longitudinally aligned with axis N. The axis N is arranged at an angle to the exhaust pipe21a′ and the exhaust silencer21s, which are aligned to have the gas flow passing therethrough substantially aligned with an axis C′, the axis C′ being substantially perpendicular to the ground. An exhaust connecting pipe21cfluidly connects the SCR21′ with the silencer21s. The rest of the exhaust gas treatment system10′ functions similarly to the exhaust gas treatment system10.

Importantly, in the embodiment ofFIG.10, the SCR21′ is inclined relative to the coolant pipes41,44,51and54, which are positioned vertically relative to the ground as in the previous embodiment. For this embodiment, it is only the orientation of the SCR21′ which is changed relative to the rest of the cooling system30.

In yet a further embodiment, as is best seen inFIG.9, feed pipe section43′ extends horizontally before extending vertically to meet with diameter expansion44. Furthermore, return pipe section53′ extends vertically downwards/depends from the port13band sub section53″ before extending vertically to meet with diameter expansion54. This arrangement may be used on either the feed port13aor the return port13b. As such, in alternative embodiments, pipes connected to the ports13aand13bmay depend from the ports before turning to extend vertically relative to the ground and substantially parallel to the axis C.

As such, it will be appreciated that the portion of tube and/or pipe that exits either of port13aand/or13bmay extend in any direction relative to the ports13aand/or13b, before turning to extend substantially vertically relative to the ground. The pipe routings from the ports13aand13bmay be symmetrical or different depending on the requirements of the construction.

It will be understood that the second feed and return pipe section42,52are in fluid communication with the third feed and return pipe section43,53either directly or via the diameter expansions44,54. Indeed in some embodiments, the second feed and return pipe section42,52may be in direct communication with the ports13aand13brespectively. The diameter expansions44,54may simply be formed as localized expansions of a continuous pipe.

Furthermore, in alternative embodiments, the bypass line60may be positioned elsewhere so that the feed and return lines are in fluid communication. This could be between the second feed and return pipe sections42,52of for example the third feed and return pipe sections43,53or indeed between the diameter expansions44,54.

It is to be understood that the terms portion and section are generally interchangeable and refer to a part of a pipe tube or conduit.

In the foregoing, the applicants have described a cooling system for a tractor exhaust after treatment. The cooling system comprises a urea supply module have a first port and a second port; and an exhaust system, wherein the exhaust system comprises an exhaust pipe, and a catalytic converter. An engine cooling system comprises a heat exchanger, a fan, a coolant pump, a coolant feed line, and a coolant return line. The coolant feed line comprises a first portion and a section portion, and the coolant return line comprises a primary portion and a secondary portion and wherein each of the first portion, the second portion, the primary portion and the secondary portion are oriented generally vertically. The second portion is in fluid communication with the first port, the secondary portion is in fluid communication with the second port, and a bypass line provides fluid communication between the second and secondary portions

The disclosure is not limited to the embodiments or examples described herein, and may be modified or adapted without departing from the scope of the present disclosure.