Device, method, and system for emissions control

Various embodiments for an exhaust gas treatment device for a vehicle system are provided. In one example, the vehicle system includes an engine with a longitudinal axis, where a crankshaft of the engine is parallel to the longitudinal axis and an exhaust gas treatment device mounted on the engine, vertically above the engine such that a longitudinal axis of the exhaust gas treatment device is aligned in parallel with the longitudinal axis of the engine, the exhaust gas treatment device configured to receive exhaust gas from an exhaust manifold of the engine.

FIELD

Embodiments of the subject matter disclosed herein relate to exhaust gas treatment devices and systems for an engine.

BACKGROUND

An exhaust gas treatment device may be included in an exhaust system of an engine in order to reduce regulated emissions. In one example, the exhaust gas treatment device may include a diesel particulate filter (DPF) or other particulate matter filter. When a DPF is included, regeneration may be employed to clean the filter by increasing the temperature for burning particulate matter that has collected in the filter. Passive regeneration may occur when a temperature of the exhaust gas is high enough to burn the particulate matter in the filter. In some examples, such as when the DPF is positioned downstream of a turbocharger, the exhaust gas may not have a high enough temperature and active regeneration may be carried out. During active regeneration, fuel may be injected and burned in the exhaust passage upstream of the DPF in order to drive the temperature of the DPF up to a temperature where the particulate matter will burn. As such, fuel consumption is increased, thereby decreasing fuel economy.

Additionally, the exhaust gas treatment device may be suspended above the engine with a support structure mounted to a main frame, or block, of the engine. However, mounting the support structure to the engine main frame may provide a limited number of mounting points along a length of the engine, due to interference with other engine systems. As a result, exhaust aftertreatment support structures may be bulky or provide less support. Further, maintenance of a head of the engine may require removal of the entire support structure and exhaust gas treatment device.

BRIEF DESCRIPTION

In one embodiment, a vehicle system includes an engine with a longitudinal axis, where a crankshaft of the engine is parallel to the longitudinal axis; and an exhaust gas treatment device mounted on the engine, vertically above the engine such that a longitudinal axis of the exhaust gas treatment device is aligned in parallel with the longitudinal axis of the engine, the exhaust gas treatment device configured to receive exhaust gas from an exhaust manifold of the engine.

DETAILED DESCRIPTION

The following description relates to various embodiments of a vehicle system including an engine and an exhaust gas treatment device mounted vertically above the engine. For example, a longitudinal axis of the exhaust gas treatment device may be aligned in parallel with a longitudinal axis of the engine and positioned vertically above the engine. A crankshaft of the engine may be parallel to the longitudinal axis. In one example, the exhaust gas treatment device may include one or more selective catalytic reduction (SCR) catalysts. The exhaust gas treatment device may additionally include a particulate filter (PF) and/or additional catalysts (such as an oxidation catalyst). In another example, the exhaust gas treatment device may be a non-SCR system including one or more of a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF). Additionally, the elements of the exhaust gas treatment device may be coated with various catalytic coatings. Further still the vehicle system may include a turbocharger positioned either upstream or downstream from the exhaust gas treatment device.

FIG. 1shows an embodiment of a vehicle system including an engine, turbocharger, and exhaust gas treatment device. As shown inFIG. 2andFIGS. 14-16, the exhaust gas treatment device may be mounted vertically above the engine. The vehicle system may further include a support structure, as depicted inFIGS. 14-21, for mounting the exhaust gas treatment device to the engine and vertically above the engine. Further, the engine and the exhaust gas treatment device may fit within an engine cab, such as the engine cab shown inFIG. 3. The exhaust gas treatment device may include various combinations of treatment devices, such as an oxidation catalyst, a particulate filter, a SCR catalyst, or the like. As one example, the exhaust gas treatment device may include a first substrate coated with a low temperature catalyst configured to operate under a first, low temperature range. As used herein, “low temperature catalyst” implies a catalyst that is active in a relatively low temperature range (e.g., between 150° C. and 300° C.). The exhaust gas treatment device may further include a second substrate coated with a high temperature catalyst positioned downstream of the first substrate, the high temperature catalyst configured to operate under a second, high temperature range. As used herein, “high temperature catalyst” implies a catalyst that is active at relatively high temperatures (e.g., between 300° C. and 600° C.). It should be understood the temperature ranges “between 150° C. and 300° C.” and “between 300° C. and 600° C.” are provided as examples and are not meant to be limiting. As such, temperatures outside these ranges may also be used. Example arrangements and operation of the catalyst-coated substrates are shown inFIGS. 4-13.

In some embodiments, the low temperature catalyst may facilitate formation of an oxidizer, such as NO2, which consumes particulate matter in the second substrate when exhaust gas temperature is in the first, low temperature range. Further, the high temperature catalyst may facilitate consumption of particulate matter in the second substrate by an exhaust gas constituent, such as O2, when the exhaust gas temperature is in the second, high temperature range. In some examples, the exhaust gas treatment device may be positioned upstream of a turbocharger in an exhaust passage of an engine where exhaust gas has a higher temperature. As such, a build-up of particulate matter in the substrates may be reduced, thereby reducing a frequency of active regeneration

In some embodiments, the exhaust gas treatment device may be configured for an engine in a vehicle, such as a rail vehicle. For example,FIG. 1shows a block diagram of an example embodiment of a vehicle system100(e.g., a locomotive system), herein depicted as a rail vehicle107, configured to run on a rail102via a plurality of wheels112. As depicted, the rail vehicle includes an engine system101with an engine104. In other non-limiting embodiments, engine104may be a stationary engine, such as in a power-plant application, or an engine in a marine vessel or off-highway vehicle propulsion system.

The engine receives intake air for combustion from an intake passage114. The intake passage receives ambient air from an air filter (not shown) that filters air from outside of the rail vehicle. Exhaust gas resulting from combustion in the engine is supplied to an exhaust passage116. Exhaust gas flows through the exhaust passage, and out of an exhaust stack of the rail vehicle. In one example, the engine is a diesel engine that combusts air and diesel fuel through compression ignition. In other non-limiting embodiments, the engine may combust fuel including gasoline, kerosene, biodiesel, or other petroleum distillates of similar density through compression ignition (and/or spark ignition).

The engine system includes a turbocharger120that is arranged between the intake passage and the exhaust passage. The turbocharger increases air charge of ambient air drawn into the intake passage in order to provide greater charge density during combustion to increase power output and/or engine-operating efficiency. The turbocharger may include a compressor (not shown) which is at least partially driven by a turbine (not shown). While in this case a single turbocharger is included, the system may include multiple turbine and/or compressor stages.

The engine system101further includes an exhaust gas treatment device130coupled in the exhaust passage upstream of the turbocharger. As will be described in greater detail below, the exhaust gas treatment device may include one or more components. In one example embodiment, the exhaust gas treatment device may include a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF), where the DOC is positioned upstream of the DPF in the exhaust gas treatment device. In other embodiments, the exhaust gas treatment device130may additionally or alternatively be a selective catalytic reduction (SCR) catalyst, three-way catalyst, NOxtrap, various other emission control devices or combinations thereof. For example, in some embodiments, the exhaust gas treatment device may be a non-SCR system that does not include any SCR catalysts, but may include additional types of catalysts or exhaust gas treatment components, as described further below.

Further, in some embodiments, a burner may be included in the exhaust passage such that the exhaust stream flowing through the exhaust passage upstream of the exhaust gas treatment device may be heated. In this manner, a temperature of the exhaust stream may be increased to facilitate active regeneration of the exhaust gas treatment device. In other embodiments, a burner may not be included in the exhaust gas stream.

The engine system further includes an exhaust gas recirculation (EGR) system141, which routes exhaust gas from the exhaust passage upstream of the exhaust gas treatment device to the intake passage downstream of the turbocharger. The EGR system includes an EGR passage143and an EGR valve145for controlling an amount of exhaust gas that is recirculated from the exhaust passage of the engine to the intake passage of the engine. By introducing exhaust gas to the engine, the amount of available oxygen for combustion is decreased, thereby reducing the combustion flame temperatures and reducing the formation of nitrogen oxides (e.g., NOx). The EGR valve may be an on/off valve controlled by the controller148, or it may control a variable amount of EGR, for example. In some embodiments, as shown inFIG. 1, the EGR system further includes an EGR cooler147to reduce the temperature of the exhaust gas before it enters the intake passage. As shown in the non-limiting example embodiment ofFIG. 1, the EGR system is a high-pressure EGR system. In other embodiments, the engine system may additionally or alternatively include a low-pressure EGR system, routing EGR from downstream of the turbine to upstream of the compressor.

The rail vehicle further includes a controller148to control various components related to the vehicle system. In one example, the controller includes a computer control system. The controller further includes computer readable storage media (not shown) including code for enabling on-board monitoring and control of rail vehicle operation. The controller, while overseeing control and management of the vehicle system, may be configured to receive signals from a variety of engine sensors150, as further elaborated herein, in order to determine operating parameters and operating conditions, and correspondingly adjust various engine actuators to control operation of the rail vehicle. For example, the controller may receive signals from various engine sensors150including, but not limited to, engine speed, engine load, boost pressure, exhaust pressure, ambient pressure, exhaust temperature, etc. Correspondingly, the controller may control the vehicle system by sending commands to various components such as traction motors, alternator, cylinder valves, throttle, etc. In one example, the controller may adjust the position of the EGR valve in order to adjust an air-fuel ratio of the exhaust gas or to modulate a temperature of the exhaust gas.

In one example embodiment, the vehicle system is a locomotive system which includes an engine cab defined by a roof assembly and side walls. The locomotive system further comprises an engine positioned in the engine cab such that a longitudinal axis of the engine is aligned in parallel with a length of the cab. For example, a crankshaft of the engine is parallel to the longitudinal axis of the engine. Further, an exhaust gas treatment device is included, and is mounted on the engine within a space defined by a top surface of an exhaust manifold of the engine, the roof assembly, and the side walls of the engine cab such that a longitudinal axis of the exhaust gas treatment device is aligned in parallel with the longitudinal axis of the engine. An embodiment of a system for mounting the exhaust gas treatment device vertically above the engine is shown inFIGS. 14-21, as described further below. In one example, the exhaust gas treatment device includes a first substrate coated with a low temperature catalyst positioned upstream of a second substrate coated with a high temperature catalyst. The exhaust gas treatment device may be disposed upstream of a turbine of the turbocharger and is configured to receive exhaust gas from the exhaust manifold of the engine. In an alternate embodiment, the exhaust gas treatment device may include one or more SCR catalysts and may be disposed downstream of the turbine of the turbocharger, as shown inFIG. 14.

Turning toFIG. 2, an example engine system201is illustrated, the engine system including an engine203, such as the engine104described above with reference toFIG. 1.FIG. 2is approximately to-scale. The engine system further includes a turbocharger205mounted on a front side of the engine and an exhaust gas treatment device209positioned on a top portion of the engine.

In the example ofFIG. 2, the engine is a V-engine which includes two banks of cylinders that are positioned at an angle of less than 180 degrees with respect to one another such that they have a V-shaped inboard region and appear as a V when viewed along a longitudinal axis of the engine. The longitudinal axis of the engine is defined by its longest dimension in this example. In the example ofFIG. 2, and inFIG. 3, the longitudinal direction is indicated by206, the vertical direction is indicated by204, and the lateral direction is indicated by208of axis system202. Each bank of cylinders includes a plurality of cylinders. Each of the plurality of cylinders includes an intake valve which is controlled by a camshaft to allow a flow of compressed intake air to enter the cylinder for combustion. Each of the cylinders further includes an exhaust valve which is controlled by the camshaft to allow a flow of combusted gases (e.g., exhaust gas) to exit the cylinder.

In the example embodiment ofFIG. 2, the exhaust gas exits the cylinder and enters an exhaust manifold positioned within the V (e.g., in an inboard orientation). In other embodiments, the exhaust manifold may be in an outboard orientation, for example, in which the exhaust manifold is positioned outside of the V. In the example ofFIG. 2, the engine is a V-12 engine. In other examples, the engine may be a V-6, V-16, I-4, I-6, I-8, opposed 4, or another engine type.

As mentioned above, the engine system includes a turbocharger positioned at a front end211of the engine. In the example ofFIG. 2, the front end of the engine is facing toward a right side of the page. Intake air flows through the turbocharger where it is compressed by a compressor of the turbocharger before entering the cylinders of the engine. In some examples, the engine further includes a charge air cooler which cools the compressed intake air before it enters the cylinder of the engine. The turbocharger is coupled to the exhaust manifold of the engine such that exhaust gas exits the cylinders of the engine and then flows through an exhaust passage218and enters an exhaust gas treatment device209before entering a turbine of the turbocharger. At locations upstream of the turbocharger, exhaust gas may have a higher temperature and a higher volume flow rate than at locations downstream of the turbocharger due to decompression of the exhaust gas upon passage through the turbocharger.

In other embodiments, the exhaust gas treatment device may be positioned downstream of the turbocharger. As an example, if the exhaust gas treatment device is positioned in a rail vehicle that passes through tunnels (e.g., tunneling), a temperature of the exhaust gas may increase upon passage through a tunnel In such an example, exhaust gas may have a higher temperature after passing through the turbocharger and passive regeneration of the exhaust gas treatment may occur, as will be described in greater detail below.

In the example embodiment shown inFIG. 2, the exhaust gas treatment device is positioned vertically above the engine. The exhaust gas treatment device is positioned on top of the engine such that it fits within a space defined by a top surface of an exhaust manifold of the engine, a roof assembly303of an engine cab301, and the side walls305of the engine cab. The engine cab301is illustrated inFIG. 3. The engine may be positioned in the engine cab such that the longitudinal axis of the engine is aligned in parallel with a length of the cab. As depicted inFIG. 2, a longitudinal axis of the exhaust gas treatment device is aligned in parallel with the longitudinal axis of the engine. One embodiment of a support structure for supporting the exhaust gas treatment device vertically above the engine is shown inFIGS. 14-21, as described further below. For example, as explained further below with reference toFIGS. 14-21, a first end of the support structure may be coupled to an engine head of the engine and a second end of the support structure may be configured to support (e.g., hold) the exhaust gas treatment device, the second end positioned vertically above the first end with respect to the vertical direction.

The exhaust gas treatment device is defined by the exhaust passage aligned in parallel with the longitudinal axis of the engine. In the example embodiment shown inFIG. 2, the exhaust gas treatment device includes a first substrate coated with a low temperature catalyst221and a second substrate coated with a high temperature catalyst222. As an example, the first substrate coated with the low temperature catalyst220may be a DOC and the second substrate coated with the high temperature catalyst222may be a cataylzed DPF, as will be described in greater detail below with reference toFIGS. 4 and 5. As shown inFIG. 2, the exhaust gas treatment device is a non-SCR system not including a SCR catalyst.

In other non-limiting embodiments, the engine system may include more than one exhaust gas treatment device, such as DOC, a DPF coupled downstream of the DOC, and a selective catalytic reduction (SCR) catalyst coupled downstream of the diesel particulate filter. In another example embodiment, the exhaust gas treatment device may include an SCR system for reducing NOxspecies generated in the engine exhaust stream and a particulate matter (PM) reduction system for reducing an amount of particulate matter, or soot, generated in the engine exhaust stream. The various exhaust after-treatment components included in the SCR system may include an SCR catalyst, an ammonia slip catalyst (ASC), and a structure (or region) for mixing and hydrolyzing an appropriate reductant used with the SCR catalyst, for example. The structure or region may receive the reductant from a reductant storage tank and injection system, for example.

In another embodiment, the exhaust gas treatment device may include a plurality of distinct flow passages aligned in a common direction (e.g., along the longitudinal axis of the engine). In such an embodiment, each of the plurality of flow passages may include one or more exhaust gas treatment devices which may each include a low temperature catalyst and a low temperature catalyst.

By positioning the exhaust gas treatment device on top of the engine such that the exhaust passage is aligned in parallel with the longitudinal axis of the engine, as described above, a compact configuration can be enabled. In this manner, the engine and exhaust gas treatment device can be disposed in a space, such as an engine cab as described above, where the packaging space may be limited.

Further, by positioning the exhaust gas treatment device upstream of the turbocharger, further compaction of the configuration may be enabled. For example, upstream of the turbocharger, exhaust gas emitted from the engine is still compressed and, as such, has a greater volume flow rate than exhaust gas that has passed through the turbocharger. As a result, a size of the exhaust gas treatment device may be reduced.

Continuing toFIG. 4, it shows an example embodiment of an exhaust gas treatment device401with a first substrate403coated with a low temperature catalyst and a second substrate405coated with a high temperature catalyst, where the second substrate is disposed downstream of the first substrate, such as exhaust gas treatment device209described above with reference toFIG. 2.

The first substrate may be a metallic (e.g., stainless steel, or the like) or a ceramic substrate, for example, with a monolithic honeycomb structure. The low temperature catalyst may be a coating of precious metal such as a platinum group metal (e.g., platinum, palladium, or the like) on the first substrate. Under a low temperature range, such as between 150° C. and 300° C., the low temperature catalyst may facilitate a chemical reaction. As such, the low temperature catalyst may operate during low load or idle conditions. In one embodiment, the low temperature catalyst may be a nitrogen oxide based catalyst that converts NO to NO2. As an example, the first substrate coated with the low temperature catalyst may be a diesel oxidation catalyst.

The second substrate may be a ceramic (e.g., cordierite) or silicon carbide substrate, for example, with a monolithic honeycomb structure. The high temperature catalyst may be a coating of an oxidized ceramic material and/or a mineral on the second substrate. For example, the high temperature catalyst may be a base metal and/or a rare earth oxide (e.g., iron, copper, yttrium, dysprosium, and the like). Under a high temperature range, such as between 300° C. and 600° C., the high temperature catalyst may facilitate a chemical reaction. As such, the high temperature catalyst may operate during high load conditions or, in the case of a rail vehicle, when the rail vehicle is passing through a tunnel In one embodiment, the high temperature catalyst may be an oxygen based catalyst that facilitates particulate matter (e.g., soot) consumption with excess O2in the exhaust stream. As an example, the second substrate coated with the high temperature catalyst may be a catalyzed diesel particulate filter. In some embodiments, the diesel particulate filter may be a wall flow particulate filter. In other embodiment, the diesel particulate filter may be a flow through particulate filter.

Thus, one embodiment relates to an exhaust gas treatment device. The device comprises a first substrate coated with a low temperature catalyst, which is a platinum group metal (e.g., platinum, palladium, ruthenium, rhodium, osmium, or iridium). The device further comprises a second substrate coated with a high temperature catalyst, which is at least one of a base metal and a rare earth oxide (e.g., iron, nickel, lead, zinc, cerium, neodymium, lanthanum, and the like), positioned downstream of the first substrate. The first and second substrates may be co-located in a common housing, the housing defining a passageway, and the first substrate located on an upstream end of the passageway.

In an embodiment, an exhaust gas treatment device comprised a first substrate coated with a low temperature catalyst, which is a mixture of platinum and rhodium. The device further comprises a second substrate coated with a high temperature catalyst, which is cerium oxide, positioned downstream of the first substrate. The first and second substrates may be co-located in a common housing, the housing defining a passageway, and the first substrate located on an upstream end of the passageway.

In an embodiment, an exhaust gas treatment device comprises a housing defining an internal passageway and a particulate matter filter in the passageway. The exhaust gas treatment device further comprises a first catalyst and a second catalyst disposed in the internal passageway, wherein the first catalyst is configured to oxidize particulate matter in the particulate matter filter in a first, low temperature range, and wherein the second catalyst is configured to oxidize particulate matter in the particulate matter filter in a second, high temperature range, and wherein the first and second catalysts operate to maintain a balance point of particulate loading of the particulate matter filter within a loading range.

Balance point operation of the particulate matter filter may be operation in which particulate matter builds up on the filter at a particular rate and, due to catalyst operation, the particulate matter is consumed at a particular rate. For example, the balance point may be an equilibrium point in which build up and consumption of particulate matter occurs at substantially the same rate. The balance point may be based on engine operation, for example, such as exhaust temperature and engine load. Further, the balance point may be different for different particulate matter filters. As an example, a wall flow particulate matter filter may have a 90 percent capture rate of particulate matter, and a flow through particulate filter may have a 50 to 60 percent capture rate of particulate matter. Thus, the wall flow particulate matter filter may have a higher balance point than the flow through particulate matter filter.

As the balance point increases, particulate matter loading may increase, and as the balance point decreases, particulate matter consumption may increase. As the particulate matter loading reaches a critical point (e.g., the balance point increases to a critical point), active regeneration of the particulate matter filter may be initiated. As an example, the critical point may be a threshold amount of particulate matter in the filter, above which the effectiveness of the particulate matter filter decreases. Thus, the critical point may be a particulate matter filter loading at which active regeneration is initiated to remove particulate matter from the particulate matter filter. As such, the balance point may be maintained in a loading range below the critical point such that initiation of active regeneration is reduced. In one non-limiting embodiment, the loading range of the balance point may be within 20 to 30 percent of a critical point at which active regeneration of the particulate matter filter is initiated.

In another embodiment, an exhaust gas treatment device comprises a housing defining an internal passageway and a particulate matter filter in the passageway. The exhaust gas treatment device further comprises one or more catalysts disposed in the internal passageway, wherein the one or more catalysts are configured to oxidize particulate matter in the particulate matter filter in a first, low temperature range and in a second, high temperature range. Further, the low temperature operation will have a peak effectiveness at a certain temperature (e.g., between 150° C. and 300° C.). The effectiveness of the high temperature operation will increase with higher and higher temperature (e.g., between 300° C. and 600° C.).

FIG. 5shows a graph501illustrating a particulate matter reduction in an exhaust gas treatment device, such as exhaust gas treatment device401described above with reference toFIG. 4, as a function of temperature. Curve505shows the temperature range in which the low temperature catalyst (e.g., the diesel oxidation catalyst) is most effective, which is in the temperature range between 150° C. and 300° C. Curve507shows the temperature range in which the high temperature catalyst (e.g., the catalyzed diesel particulate filter) is most effective, which is in the temperature range between 300° C. and 600° C.

As indicated by the curve505inFIG. 5, at lower exhaust temperatures, soot on the second substrate may be reduced by the low temperature catalyst. Further, at higher exhaust temperatures, the low temperature catalyst may not be effective due to its lower NO2conversion ratio. As such, the second substrate may be coated with a second, high temperature catalyst that facilitates the reduction of soot at higher exhaust temperatures.

As described above, the low temperature catalyst may be a nitrogen oxide based catalyst that converts NO to NO2. As such, the NO2formed at the first substrate may flow to the second substrate where it will consume soot, thereby cleaning the second substrate by passive regeneration during periods when the exhaust temperature is relatively low. Further, the high temperature catalyst may be an oxygen based catalyst that facilitates particulate matter consumption with excess O2in the exhaust stream. As such, during periods when the exhaust temperature is relatively high, soot consumption may occur by passive regeneration.

In other words, the low temperature catalyst (e.g., the DOC) converts NO to NO2, which oxidizes the particulates in the particulate filter. This reaction is effective over the lower temperature range of 150 to 300° C. Above 300° C. the DOC is not effective in converting NO to NO2. In the temperature range over 300° C., the high temperature catalyst (e.g., the particulate filter) is catalyzed to use the O2in the exhaust gas to oxidize the soot.

Thus, passive regeneration of the second substrate coated with the high temperature catalyst may occur over a wide range of temperatures (e.g., 150° C. and 600° C.), as indicated by curve503shown inFIG. 5. In this manner, a need for active regeneration due to particulate matter build-up in the second substrate may be reduced. As such, fuel consumption may be reduced as fuel injection for increasing temperature for active regeneration is reduced.

FIG. 6shows another example embodiment of an exhaust gas treatment device600. The exhaust gas treatment device600includes first substrate coated with a low temperature catalyst and a second substrate coated with a high temperature catalyst, such as the first substrate403and the second substrate405described above with reference toFIG. 4. In the example embodiment ofFIG. 6, each of the catalysts is divided into a plurality of sub-substrates which split the exhaust flow into a corresponding number of portions.

In the example embodiment ofFIG. 6, the first substrate is divided into a first sub-substrate603and a second sub-substrate605disposed downstream of the first sub-substrate603, thereby splitting the exhaust gas flow into two different portions. As depicted, the first sub-substrate603extends partially across a radial extent of the exhaust gas treatment device such that a portion of the radial extent at the location of the first sub-substrate is not filled by the first sub-substrate. As such, a first portion of exhaust gas flows through the first sub-substrate603and a second portion of exhaust gas bypasses the first sub-substrate603and flows through the second sub-substrate605. As depicted, the second sub-substrate605extends partially across a radial extent of the exhaust gas treatment device such that a portion of the radial extent at the second sub-substrate is not filled by the second sub-substrate. In some embodiments, the first sub-substrate603and the second sub-substrate605may be coated by the same low temperature catalyst. In other embodiments, the first sub-substrate603and the second sub-substrate605may be coated by different low temperature catalysts.

Further, a flow divider611interconnects distal edges of the first sub-substrate603and the second sub-substrate605that are not abutting the walls of the exhaust gas treatment device600. In this manner, the flow divider channels exhaust gas around each of the sub-substrates603and605such that each portion of exhaust gas flow flows through only one of the sub-substrates603and605.

Further, in the example embodiment ofFIG. 6, the second substrate is divided into a first sub-substrate607and a second sub-substrate609disposed downstream of the first sub-substrate, thereby splitting the exhaust gas flow into two different portions. The second substrate is disposed downstream of the first substrate. As depicted, the first sub-substrate607extends partially across a radial extent of the exhaust gas treatment device such that a portion of the radial extent at the location of the first sub-substrate is not filled by the first sub-substrate. As such, a first portion of exhaust gas flows through the first sub-substrate607and a second portion of exhaust gas bypasses the first sub-substrate607and flows through the second sub-substrate609. As depicted, the second sub-substrate609extends partially across a radial extent of the exhaust gas treatment device such that a portion of the radial extent at the second sub-substrate is not filled by the second sub-substrate. In some embodiments, the first sub-substrate607and the second sub-substrate609may be coated by the same high temperature catalyst. In other embodiments, the first sub-substrate607and the second sub-substrate609may be coated by different high temperature catalysts.

Further, a flow divider611interconnects distal edges of the first sub-substrate607and the second sub-substrate609that are not abutting the walls of the exhaust gas treatment device600. In this manner, the flow divider channels exhaust gas around each of the sub-substrates607and609such that each portion of exhaust gas flow flows through only one of the sub-substrates607and609.

By dividing the first sub-substrate into two sub-substrates603and605, and dividing the second substrate into two sub-substrates607and609, a surface area through which exhaust gas flows may be increased and a length along which each portion flows may be decreased, thereby reducing a pressure drop on the system. Further, in such a configuration, a size of the exhaust gas treatment device may be reduced thus enabling the device to be positioned in a system that has limited space. As such, a more compact exhaust gas treatment device may be enabled, the more compact exhaust gas treatment device capable of passive regeneration over a wide range of temperatures, as described with reference toFIGS. 4 and 5.

It should be understoodFIG. 6is provided as an example. The exhaust gas treatment device may include any suitable number of sub-substrates splitting the exhaust flow into a corresponding number of flow paths. In some embodiments, only the first substrate may be divided or only the second substrate may be divided. Further, a size and shape of each sub-substrate may vary based on the configuration of the sub-substrates within the exhaust gas treatment device.

FIG. 7shows a high level flow chart illustrating a method700for an exhaust gas treatment device, such as the exhaust gas treatment device401or600described above with reference toFIGS. 4 and 6, respectively.

At701of method700, under exhaust gas temperatures between 150° C. and 300° C., nitric oxide (NO) is converted to nitrogen dioxide (NO2) in the diesel oxidation catalyst (DOC). As described above, the DOC may be coated with a low temperature catalyst, such as platinum, which facilitates the reaction. The NO2formed in the DOC flows to the diesel particulate filter (DPF) where it oxidizes particulate matter, such as soot, thereby passively regenerating the DPF at low temperatures.

At703of method700, under exhaust gas temperatures between 300° C. and 600° C., particulate matter such as soot is oxidized in the DPF with excess oxygen in the exhaust gas, thereby passively regenerating the DPF at high temperatures. As described above, the DPF may be coated with a high temperature catalyst which facilitates the oxidation of soot.

Thus, the DPF may be regenerated by passive regeneration over a wide range of temperatures. In this manner, fuel consumption may be reduced, thereby increasing fuel economy, as active regeneration may be carried out less frequently due to an increase in passive regeneration.

Another embodiment relates to an exhaust gas treatment device. The device comprises a first substrate and a second substrate positioned downstream of the first substrate. (For example, the first and second substrates may be located in a common passageway defined by a housing.) The first substrate is coated with a low temperature catalyst configured to operate under a first, low temperature range. The low temperature catalyst converts nitric oxide to nitrogen dioxide in the first, low temperature range. The second substrate is coated with a high temperature catalyst. The high temperature catalyst is configured to operate under a second, high temperature range. In the first and second temperature ranges, particulate matter is oxidized at the second substrate. More specifically, the nitrogen dioxide (generated by the low temperature catalyst and traveling downstream to the second substrate) oxidizes particulate matter in the second substrate in the first, low temperature range. Additionally, the high temperature catalyst reduces particulate matter in the second substrate with oxygen in exhaust gas when a temperature of the exhaust gas is in the second, high temperature range.

In another embodiment, an exhaust gas treatment device comprises a diesel oxidation catalyst and a diesel particulate filter located downstream of the diesel oxidation catalyst. The diesel oxidation catalyst has a first catalyst for converting nitric oxide to nitrogen dioxide for oxidizing particulate matter in the diesel particulate filter in a first, low temperature range. The diesel particulate filter has a second catalyst for oxidizing particulate matter in the diesel particulate filter in a second, high temperature range.

In another embodiment, an exhaust gas treatment device comprises a housing defining an internal passageway, a particulate matter filter in the passageway, and a plurality of catalysts disposed in the internal passageway. The plurality of catalysts is configured to oxidize particulate matter in the particulate matter filter in a first, low temperature range and in a second, high temperature range (e.g., one catalyst may work in the low temperature range, and another catalyst in the high temperature range).

In some examples, an engine system may be retrofitted with an exhaust gas treatment device as described in any of the embodiments herein. The exhaust gas treatment device may be added to the engine system in any suitable location in the exhaust passage, for example, the exhaust gas treatment device may be installed upstream or downstream of the turbine of the turbocharger.

Further, in some examples, an engine may be serviced by replacing an exhaust gas treatment device with an exhaust gas treatment device as described in any of the embodiments herein. In such an example, the exhaust gas treatment device may be replaced such that fuel economy of the engine system may be increased.

FIGS. 8-11show additional possible arrangements for the exhaust gas treatment device introduced above with reference toFIGS. 1-2. For example,FIGS. 8-11show embodiments of an oxidation catalyst, such as a diesel oxidation catalyst (DOC), and embodiments of the oxidation catalyst disposed in an exhaust gas treatment device. In particular,FIG. 8shows an exemplary embodiment of an oxidation catalyst device which includes a first substrate and a second substrate positioned coaxially, whileFIG. 9shows an example embodiment of the oxidation catalyst device depicted inFIG. 8disposed in an exhaust gas treatment device.FIG. 11shows an exemplary embodiment of an oxidation catalyst device with a first substrate, a second substrate positioned coaxially with the first substrate, and a flow control element which controls flow through the first substrate.FIG. 12shows an exemplary embodiment of the oxidation catalyst device depicted inFIG. 11disposed in an exhaust gas treatment device.

FIG. 8shows an oxidation catalyst device800with a first substrate803and a second substrate805positioned coaxially with the first substrate. The first substrate may be a metallic (e.g., stainless steel, or the like) or a ceramic substrate, for example, with a monolithic honeycomb structure. Similarly, the second substrate may be a metallic (e.g., stainless steel, or the like) or a ceramic substrate, for example, with a monolithic honeycomb structure. In some examples, the first substrate and the second substrate may be made of the same material. In other examples, the first substrate and the second substrate may be made of different materials.

The first substrate may be coated with a low temperature catalyst. As an example, the low temperature catalyst may be platinum. Under a low temperature range, such as between 300° C. and 500° C., the low temperature catalyst may facilitate a chemical reaction. As such, the low temperature catalyst may operate during low load or idle conditions when an exhaust temperature is relatively low. In one embodiment, the low temperature catalyst may facilitate conversion of CO and hydrocarbons to water and CO2. The low temperature catalyst may further be a nitrogen oxide-based catalyst which facilitates conversion of NO to NO2.

The second substrate may be coated with a high temperature catalyst. As an example, the high temperature catalyst may be a mixture of platinum and palladium. In one example, the high temperature catalyst may be made of four parts platinum and one part palladium by weight. Under a high temperature range, such as between 500° C. and 600° C., the high temperature catalyst may facilitate a chemical reaction. As such, the high temperature catalyst may operate during conditions when an exhaust temperature is relatively high. Conditions in which the exhaust gas temperature is relatively high may include tunneling operation in which the vehicle is travelling through a tunnel, active regeneration of the particulate filter in which the exhaust gas temperature is increased to facilitate regeneration of the particulate filter, and/or conditions in which degradation of a component such as a turbocharger has occurred. In one embodiment, the high temperature catalyst may facilitate conversion of CO and hydrocarbons to water and CO2. The high temperature catalyst may further be a nitrogen oxide-based catalyst which facilitates conversion of NO to NO2.

In one embodiment, each of the two substrates may have a different cell density. For example, the first substrate may have a higher cell density than the second substrate. In one example, the first substrate may have a cell density between 46.5 and 77.5 cell per square centimeter (300 and 500 cells per square inch) and the second substrate may have a cell density of less than 46.5 cells per square centimeter. In one non-limiting embodiment, the second substrate may have a cell density of 31 cells per square centimeter (200 cells per square inch). In this manner, the flow resistance between the substrates may be different, and as such, higher temperature and lower temperature exhaust gas flows may be more likely to flow through one substrate or the other and the exhaust gas flow may be passively directed through one substrate or the other based on the temperature. As an example, the first substrate with the higher cell density may form a first flow path along which exhaust gas flows at lower temperatures and the second substrate with the lower cell density may form a second flow path along which exhaust gas flows at higher temperatures.

As an example of the dependence of flow through a substrate and cell density,FIG. 10shows a graph1000illustrating an example of flow through a substrate based on exhaust gas temperature and substrate cell density. As depicted inFIG. 10, exhaust gas flow at a lower temperature prefers a higher substrate cell density. Exhaust gas flow at a higher temperature prefers a lower substrate cell density. By coating the substrate with a higher cell density with the low temperature catalyst and coating the substrate with the lower cell density with the high temperature catalyst, high temperature exhaust gas flows may be more likely to flow through the substrate with the lower cell density coated with the high temperature catalyst. In this manner, the degradation of the low temperature catalyst may be reduced during conditions in which the exhaust temperature is high. In some examples, lower temperature exhaust gas may flow through the first substrate (e.g.,803) coated with the low temperature catalyst and the second substrate (e.g.,805) coated with the high temperature catalyst.

Referring back toFIG. 8, the second substrate coated with the high temperature catalyst is positioned in the center of the oxidation catalyst device and the first substrate coated with the low temperature catalyst surrounds the circumference of the second substrate. It should be understood that the oxidation catalyst is not limited to this configuration. In other embodiments, the first substrate coated with the low temperature catalyst may be positioned in the center of the oxidation catalyst and the second substrate coated with the high temperature catalyst may surround the circumference of the first substrate.

By positioning the first substrate and the second substrate coaxially, each of the substrates and are in the proximity of the heat source (e.g., the exhaust gas). As such, when exhaust gas flow to one of the substrates is reduced, the temperature of the other substrate may not drop significantly such that it falls below its activation temperature. For example, when a high temperature exhaust flow flows primarily through the second substrate coated with the high temperature catalyst and the first substrate coated with the low temperature catalyst receives a reduced exhaust gas flow, the temperature of the first substrate may not drop below its activation temperature. In this manner, when the exhaust gas temperature decreases such that exhaust flow through the first substrate increases, the first substrate coated with the low temperature catalyst is ready for conversion of NO to NO2without having to wait for the first substrate to warm-up.

Turning now toFIG. 9, an exemplary embodiment of an exhaust gas treatment device900disposed in an exhaust passage902is depicted. The exhaust gas treatment device900includes the oxidation catalyst device800described above with reference toFIG. 8. As depicted, the exhaust gas treatment device900further includes a particulate filter904, such as a DPF, disposed downstream of the first substrate803and the second substrate805of the oxidation catalyst device800. The particulate filter may include a substrate such as a ceramic (e.g., cordierite) or silicon carbide substrate, for example, with a monolithic honeycomb structure. In some examples, such as described above with reference toFIGS. 4 and 6, the particulate filter may be a catalyzed particulate filter coated with a catalyst. As an example, the particulate filter may be coated with a catalyst such as an oxidized ceramic material and/or a mineral, as described above. In some embodiments, the diesel particulate filter may be a wall flow particulate filter. In other embodiments, the diesel particulate filter may be a flow through particulate filter.

By positioning the particulate filter downstream of the oxidation catalyst, an oxidizer generated by the oxidation catalyst device, such as NO2, may flow to the particulate filter, thereby facilitating the oxidation of particulate matter trapped in the particulate filter. In this way, passive regeneration of the particulate filter may be carried out over a range of exhaust gas temperatures (e.g., 300-600° C.), and a need for active regeneration of the particulate filter may be reduced.

FIG. 11shows another example of an oxidation catalyst device1100, such as a DOC, which includes a first substrate1102coated with a first, low temperature catalyst and a second substrate1104coated with a second, high temperature catalyst. As described above, the first substrate1102and the second substrate1104may be metallic (e.g., stainless steel, or the like) or ceramic substrates, for example, with a monolithic honeycomb structure. In some examples, the first substrate1102and the second substrate1104may be made of the same material. In other examples, the first substrate1102and the second substrate1104may be made of different materials.

The first substrate1102may be coated with a low temperature catalyst. As an example, the low temperature catalyst may be platinum. The low temperature catalyst may facilitate a chemical reaction under a low temperature range, such as between 300° C. and 500° C. As such, the low temperature catalyst may operate during low load or idle conditions when an exhaust temperature is relatively low. In one embodiment, the low temperature catalyst may facilitate conversion of CO and hydrocarbons to water and CO2. The low temperature catalyst may further be a nitrogen oxide-based catalyst which facilitates conversion of NO to NO2.

The second substrate1104may be coated with a high temperature catalyst. As an example, the high temperature catalyst may be a mixture of platinum and palladium. In one example, the high temperature catalyst may be made of four parts platinum and one part palladium by weight. The high temperature catalyst may facilitate a chemical reaction under a high temperature range, such as between 500° C. and 600° C. As such, the high temperature catalyst may operate during conditions when an exhaust temperature is relatively high, as described above. For example, conditions in which the exhaust gas temperature is relatively high may include tunneling operation, active regeneration of the particulate filter, and/or conditions in which degradation of a component such as a turbocharger has occurred. In one embodiment, the high temperature catalyst may facilitate conversion of CO and hydrocarbons to water and CO2. The high temperature catalyst may further be a nitrogen oxide-based catalyst which facilitates conversion of NO to NO2.

As depicted inFIG. 11, the oxidation catalyst device1100further includes a flow control element1106operably coupled with the first substrate1102which may be controlled by a controller, such as the controller148described above with reference toFIG. 1, in order to actively direct the exhaust gas flow along a first flow path through the first substrate1102or along a second flow path through the second substrate1104. In the example embodiment depicted inFIG. 11, the first substrate1102is disposed in a housing1108, such as a pipe or other suitable conduit. The flow control element1106may be a valve, such as an on/off valve, a flow control valve, or a diverter valve. In other examples, the flow control element1106may be a flap that is capable of covering and blocking exhaust gas flow to the first substrate1102. A position of the flow control element1106governs an extent to which exhaust gas flows through the first substrate. For example, when the flow control element is closed, exhaust gas may not pass through the first substrate1102, and, instead, is directed along a second flow path through the second substrate1104. On the other hand, when the exhaust gas valve is open, exhaust gas may flow through the first substrate1102and the second substrate1104.

The housing1108may allow at least some heat transfer between the first substrate1102and the second substrate1104. As such, even when the flow control element1106is closed so that high temperature exhaust gas does not flow through the first substrate1102, a temperature of the first substrate1102may be maintained above an activation temperature. In this manner, when the flow control element1106is opened, the temperature of the first substrate1102is greater than the activation temperature such that the low temperature catalyst coated on the first substrate1102may resume conversion of NO to NO2with little to no delay.

In some embodiments, the first substrate1102and the second substrate1104may have different cell densities, as described above with reference toFIG. 8. As an example, the first substrate1102coated with the low temperature catalyst may have a higher cell density than the second substrate1104coated with the high temperature catalyst. As the higher cell density may be more restrictive to a higher temperature exhaust gas (FIG. 10), the higher temperature exhaust gas may be more likely to flow along the second flow path through the second substrate1104with the lower cell density. When the flow control element is in an open position, the lower temperature exhaust gas may be more likely to flow along the first flow path through the first substrate1102with the higher cell density.

As depicted inFIG. 11, the first substrate1102coated with the low temperature catalyst is positioned in the center of the oxidation catalyst device1100and the second substrate1104coated with the high temperature catalyst surrounds the circumference of the first substrate1102. In other embodiments, the second substrate1104coated with the high temperature catalyst may be positioned in the center of the oxidation catalyst and the first substrate1102coated with the low temperature catalyst may surround the circumference of the second substrate1104. In such a configuration, the flow control element1106may control the flow of exhaust gas through the second substrate1104.

FIG. 12shows an exemplary embodiment of an exhaust gas treatment device1200disposed in an exhaust passage1202. The exhaust gas treatment device1200includes the oxidation catalyst device1100described above with reference toFIG. 11. As depicted, the exhaust gas treatment device1200further includes a particulate filter1204, such as a DPF or other particulate matter filter, disposed downstream of the first substrate1102and the second substrate1104of the oxidation catalyst device1100. The particulate filter1204may include a substrate such as a ceramic (e.g., cordierite) or silicon carbide substrate, for example, with a monolithic honeycomb structure. In some examples, such as described above with reference toFIGS. 4 and 6, the particulate filter1204may be a catalyzed particulate filter coated with a catalyst. As an example, the particulate filter1204may be coated with a catalyst such as an oxidized ceramic material and/or a mineral, as described above. In some embodiments, the diesel particulate filter may be a wall flow particulate filter. In other embodiments, the diesel particulate filter may be a flow through particulate filter.

The exhaust gas treatment device1200further includes a flow control element1106operably coupled to the first substrate1102via a housing1108. By adjusting the flow control element1106to direct the flow of exhaust gas through the first substrate1102or the second substrate1104, an oxidizer may be generated by the low temperature catalyst and/or high temperature catalyst during a range of exhaust gas temperatures (e.g., 300-600° C.), including low and high exhaust gas temperatures. With the particulate filter1204positioned downstream of the oxidation catalyst device1100, the oxidizers generated by the low and high temperature catalysts may flow to the particulate filter1204, and passive regeneration of the particulate filter1204may be carried out over a range of exhaust gas temperatures without degrading the low temperature catalyst.

In one embodiment, a method for an exhaust gas treatment device, such as the exhaust gas treatment device900described above with reference toFIG. 9or the exhaust gas treatment device1200described above with reference toFIG. 12, comprises the step of determining a temperature of exhaust gas flowing through the exhaust passage. The method further comprises, when the temperature of the exhaust gas is less than a threshold temperature, selectively directing the exhaust gas along a first flow path through a first substrate coated with a low temperature catalyst which converts nitric oxide to nitrogen dioxide, and when the temperature of the exhaust gas is greater than the threshold temperature, selectively directing the exhaust gas along a second flow path through a second substrate coated with a high temperature catalyst which converts nitric oxide to nitrogen dioxide, the second substrate positioned coaxially with the first substrate within the exhaust gas treatment device. The method further comprises oxidizing particulate matter with the nitrogen dioxide in a particulate filter disposed downstream of the first substrate and the second substrate.

FIG. 13shows a flow chart illustrating a method1300for an exhaust gas treatment device, such as the exhaust gas treatment device900described above with reference toFIG. 9or the exhaust gas treatment device1200described above with reference toFIG. 12. Specifically, the method determines the temperature of exhaust gas flowing through the exhaust passage and directs the flow of the exhaust gas through a first and/or second substrate of an oxidation catalyst disposed in the exhaust gas treatment device accordingly.

At1302, operating conditions are determined As non-limiting examples, the operating conditions may include engine load conditions, environmental conditions (e.g., tunneling operation, ambient temperature, ambient pressure, and the like), exhaust conditions (e.g., temperature, pressure, and the like), and the like.

At1304, the exhaust gas temperature is determined. The exhaust gas temperature may be determined based on temperature sensor measurements from temperature sensors in the exhaust passage, for example. In some examples, the method does not require determination of the specific temperature, but determination if the temperature is above or below a threshold temperature.

Once the exhaust temperature is determined, it is determined if the exhaust gas temperature is greater than a threshold temperature at1306. The threshold temperature may be based on the composition of the catalysts in the exhaust gas treatment device. In one example, the threshold temperature may be 500° C. In other examples, the threshold temperature may be greater than 500° C. or less than 500° C.

If it is determined that the exhaust gas temperature is greater than the threshold temperature, the method continues to1308where the exhaust gas flow is selectively directed along a second flow path through the second substrate coated with the high temperature catalyst. In some examples, such as in the exhaust gas treatment device depicted inFIG. 9, the exhaust gas flow may be passively directed through the second substrate based on a cell density of the substrate, as described above. For example, the second substrate coated with the high temperature catalyst may have a lower cell density than the first substrate coated with the low temperature catalyst. The higher temperature exhaust gas, which has a higher flow rate than lower temperature exhaust gas, may favor the lower cell density substrate, and as such, the high temperature exhaust flow may flow through the second substrate coated with the high temperature catalyst. In this manner, flow of high temperature exhaust gas through the first substrate coated with the low temperature catalyst may be reduced and degradation of the low temperature catalyst may be reduced.

In other examples, such as in the exhaust gas treatment device depicted inFIG. 12, the exhaust gas flow may be actively directed through the second substrate based on actuation of a flow control element, such as the flow control element1106described above with reference toFIGS. 11 and 12, as described above. For example, the flow control element may be closed once it is determined that the exhaust gas temperature is greater than the threshold temperature. In this manner, exhaust gas flow through the first substrate coated with the low temperature catalyst may be substantially reduced or cut-off, thereby reducing degradation of the low temperature catalyst.

On the other hand, if it is determined that the exhaust gas temperature is less than the threshold temperature at1306, the method moves to1310where the exhaust gas flow is directed through the first substrate coated with the low temperature catalyst. In some examples, the exhaust flow may be directed through the first substrate based on a cell density of the substrate. As described above, the first substrate coated with the low temperature catalyst may have a higher cell density than the second substrate coated with the high temperature catalyst. The lower temperature gas, which has a lower flow rate than the high temperature gas, may favor the higher cell density substrate, and as such, the low temperature exhaust flow may flow through the first substrate coated with the low temperature catalyst.

Thus, exhaust gas flow through an oxidation catalyst including a first substrate coated with a low temperature catalyst and a second substrate coated with a high temperature catalyst may be controlled based on a temperature of the exhaust gas. By controlling the flow of exhaust gas through the substrates, while not thermally isolating the substrates from the heat source, a temperature of the substrates and corresponding catalysts may be maintained above an activation temperature such that oxidizer formation may be resumed quickly when exhaust gas flow through the substrate is resumed.

The exhaust gas treatment devices (e.g., exhaust gas treatment devices130,209,401,600,900, and/or1200) shown inFIGS. 1-2, 4, 6, 9, and 12may all be supported and suspended above the engine of the engine system (e.g., engine104shown inFIG. 1or engine203shown inFIG. 2) by a support structure. An example embodiment of such a support structure is shown inFIGS. 14-21.

Turning first toFIG. 14, an engine system101including an engine104is shown (e.g., may be the same as engine system101and engine104shown inFIG. 1). As described above with reference toFIG. 1, the engine104receives intake air for combustion from the intake passage114. The intake may be any suitable conduit or conduits through which gases flow to enter the engine. For example, the intake may include an intake manifold115, the intake passage114, and the like. The intake passage114receives ambient air from an air filter (not shown) that filters air from outside of the engine104. Exhaust gas resulting from combustion in the engine104is supplied to an exhaust, such as exhaust passage116. The exhaust, or exhaust passage116, may be any suitable conduit through which gases flow from the engine. For example, the exhaust may include an exhaust manifold117, an exhaust passage116, and the like. Exhaust gas flows through the exhaust passage116and out of the engine system101.

As shown inFIG. 14, engine104is a Vee engine (e.g., V-engine) having a first bank of cylinders and a second bank of cylinders (similar to V-engine203shown inFIG. 2). In the embodiment depicted inFIG. 14, the engine104is a V-12 engine having twelve cylinders. In other examples, the engine may be a V-6, V-8, V-10, or V-16 or any suitable V-engine configuration. The engine104includes an engine block and an engine head. The engine head includes a plurality of cylinder heads, each cylinder head106including a respective cylinder. Specifically,FIG. 1shows six individual cylinder heads106for a first bank of the engine104. The other six individual cylinder heads of the second bank are hidden inFIG. 14, as they are positioned behind the six cylinder heads of the first bank.

Each cylinder head106includes a valve cover108. Additionally, each cylinder head106includes a fuel injector. Each fuel injector passes through a respective valve cover108and connects to a high pressure fuel line110. The high pressure fuel line110runs along a length of the engine104. Each cylinder head106is further coupled to the exhaust manifold117. As such, exhaust gases produced during combustion exit the cylinder heads106through the exhaust manifold117and then flow to the exhaust passage116. The exhaust passage116contains additional engine system components, including a turbine of a turbocharger120and an exhaust gas treatment device130, as described further below.

The engine system101includes a turbocharger120that is arranged between the intake passage114and the exhaust passage116. The turbocharger120increases air charge of ambient air drawn into the intake passage114in order to provide greater charge density during combustion to increase power output and/or engine-operating efficiency. The turbocharger120may include a compressor (not shown) which is at least partially driven by a turbine (not shown). While in this case a single turbocharger is included, the system may include multiple turbine and/or compressor stages.

The engine system101further includes an exhaust gas treatment device130(may also be referred to herein as an exhaust gas aftertreatment system) coupled in the exhaust passage116in order to reduce regulated emissions. As depicted inFIG. 14, the exhaust gas treatment device130is disposed downstream of the turbocharger120. In other embodiments, as shown inFIGS. 1-2, an exhaust gas treatment device may be additionally or alternatively disposed upstream of the turbocharger120. The exhaust gas treatment device130may include one or more components, as discussed above with reference toFIGS. 1-13. For example, the exhaust gas treatment device130may include one or more of a diesel particulate filter (DPF), a diesel oxidation catalyst (DOC), a selective catalytic reduction (SCR) catalyst, a three-way catalyst, a NOxtrap, and/or various other emission control devices or combinations thereof.

As one example, the exhaust gas treatment device130may be an SCR system including one or more SCR catalysts. In another example, the exhaust gas treatment device130may be a non-SCR system not including an SCR catalyst. For example, the non-SCR system may include one or more of a DPF and a DOC.

Further, as shown inFIG. 1, the exhaust gas treatment device130is positioned vertically above the engine104, with respect to a surface on which the engine104sits. The exhaust gas treatment device130sits on and is supported by a support structure140. The support structure140is directly mounted to the engine head. Specifically, the support structure140includes a plurality of support legs142. Each support leg142is mounted to a respective cylinder head106. The support structure140also includes a plurality of platforms144(only one shown inFIG. 1) coupled to the support legs142on each cylinder bank. Further, the support structure140includes coil isolators146coupled between each platform144and a surface of the exhaust gas treatment device130. As described further below, the coil isolators146may isolate the exhaust gas treatment device130from vibration generated and transmitted by the engine104. Further details of the support structure140are described below with regard toFIGS. 15-21.

In one embodiment, the engine system101may include an engine cab, such as the engine cab301shown inFIG. 3, as described above. In this embodiment, the exhaust gas treatment device130may be disposed between a top of the engine104and a ceiling (e.g., roof assembly303shown inFIG. 3) of the engine cab. As such, the support structure140may suspend the exhaust gas treatment device130above the engine104and below the ceiling of the engine cab.

The support structure introduced inFIG. 14and described further below has several advantages over previous exhaust gas treatment device support structures. Firstly, the support structure140shown inFIG. 14supports the exhaust gas treatment device through platforms. Thus, the exhaust gas treatment device ofFIG. 14is mounted to the platforms of the support structure instead of mounted to a wall of an engine cab. Secondly, the support structure140is mounted to the engine head instead of the engine block. Supporting the exhaust gas treatment device with platforms of a support structure mounted to an engine head increases stability of the support structure and exhaust gas treatment device. Mounting the exhaust gas treatment device to the engine head, through the platforms, may reduce translation of vibrations from the vehicle in which the engine is installed to the exhaust gas treatment device. Additionally, mounting the support structure directly to the engine head may allow for an increased number of mounting points, thereby reducing a size of each mounting fixture (e.g., support leg) and increasing the stability of the support structure.

FIGS. 15-21show a support structure140and its components. Specifically,FIGS. 15-16show the support structure140installed in an engine system, such as the engine system101ofFIG. 14. The engine system ofFIGS. 15-16may include like components to those described above with regard toFIG. 1,FIG. 2, and/orFIG. 14.FIGS. 17-18are detailed views of a mounting interface between the support structure140and an engine head.FIG. 19shows a support leg of the support structure140,FIG. 20shows a coil isolator of the support structure140, andFIG. 21shows a spring coil isolator of the support structure140.

Turning toFIGS. 15-16, a coordinate axis system202is depicted showing different directions in the engine system. In the example ofFIGS. 15-16, the longitudinal direction is indicated by206(e.g., longitudinal axis), the vertical direction is indicated by204(e.g., vertical axis), and the lateral direction is indicated by208(e.g., lateral axis).FIG. 15shows a schematic200of an isometric view of the support structure140in the engine system.FIG. 16shows a schematic300of a cross-section view, in the vertical-lateral plane, of the support structure140in the engine system.

As shown inFIGS. 15-16, the support structure140is coupled to an engine head210, the engine head210positioned on an engine block212, of a V-engine220(such as engine104shown inFIG. 1and/orFIG. 14). The engine head210includes a plurality of cylinder heads106. Each cylinder head106includes an individual cylinder of the engine. As described above, the V-engine220includes a plurality of cylinder heads106aligned in two separate planes or banks, so that they appear to be in a “V” when viewed along the horizontal axis206(e.g., into the page inFIG. 16).

As shown inFIG. 15, the engine head210includes six cylinder heads106on a first bank214of the engine. The engine head210also includes six cylinder heads106on a second bank302of the V-engine220(hidden inFIG. 1). As shown inFIG. 16, the first bank214and the second bank302are opposite one another with respect to a vertical centerline304of the engine. The first bank214is to the left of the centerline304and the second bank302is to the right of the centerline304. Thus, the first bank214may be referred to as the left bank and the second bank302may be referred to as the right bank. A crankshaft306of the V-engine220has an axis of rotation308in the direction of the horizontal axis206(e.g., into the page inFIG. 3). Further, the axis of rotation308of the crankshaft306is centered laterally at the centerline304.

Each of the cylinder heads106are individually mounted to the engine block212. As such, each cylinder head106is individually removable from the engine block212. Additionally, as described above with regard toFIG. 14, each cylinder head106includes a valve cover108. A high pressure fuel line110connects to a fuel injector of each cylinder head106, the fuel injectors running through respective valve covers108.

FIG. 16also shows an intake manifold115and exhaust manifolds117of the V-engine220. Intake air for combustion flows through the intake manifold115and enters each of the cylinder heads106. Exhaust gases resulting from combustion exit the cylinder heads106and enter one of two exhaust manifolds. As shown inFIG. 16, the engine system includes one exhaust manifold for the first bank214of cylinders and one exhaust manifold for the second bank302of cylinders. Exhaust gases travel through the exhaust manifolds117and into an exhaust passage116(partially shown inFIG. 15). The exhaust passage116is coupled to the exhaust gas treatment device130. Exhaust gases flow through the exhaust gas treatment device130and then exit the engine system through an exhaust stack216(shown inFIG. 15).

As introduced above inFIG. 14, the support structure140includes a plurality of support legs142, a plurality of platforms (such as the platform144shown inFIG. 1), a plurality of coil isolators146, and a plurality of rails. The support structure140may be divided into two sets of components, a first set on the first bank214of the engine and a second set on the second bank302of the engine. The first set of components on the first bank214is shown inFIG. 15. As seen inFIG. 16, the centerline304of the V-engine220is also a centerline of the support structure140. As such, the support structure is symmetric with respect to the centerline304.

For example, the plurality of platforms includes a first platform244and a second platform316. As shown inFIG. 16, the first platform244and the second platform316are on opposite sides of the centerline304from one another, with the first platform244to the left of the centerline (e.g., proximate to the first bank214) and the second platform316to the right of the centerline (e.g., proximate to the second bank302). The first platform244and the second platform316are angled at 45 degrees away from the centerline304. Specifically, the degree of angling of the platforms forms an acute angle of 45 degrees, defined between the centerline304and a side of the platform facing the exhaust gas treatment device130. The degree of angling of the platforms also forms an obtuse angle of 135 degrees between the centerline304and a side of the platform facing the cylinder heads106.

In alternate embodiments, the degree of angling (e.g., the acute angle) may be within a range of 0 to 90 degrees. For example, the range of angling of the platforms may be from 35 to 60 degrees. In one example, the degree of angling may be 60 degrees such that the first platform244and the second platform316are angled at 60 degrees away from the centerline304. In another example, the degree of angling may be 40 degrees. In yet another example, the degree of angling may be greater than 0 degrees and less than 90 degrees such that the platforms are not completely vertical and not completely lateral, with respect to the vertical axis204and the lateral axis208, respectively. The degree of angling may be based on a shape and size of the exhaust gas treatment device130. Further, the degree of angling may be defined such that the platforms support and cradle the exhaust gas treatment device130, thereby reducing additional assembly tooling for mounting the exhaust gas treatment device130to the support structure140.

The exhaust gas treatment device130is positioned vertically above the V-engine220with respect to the vertical axis204and a surface on which a vehicle or other powered system in which the V-engine220is installed sits (such as the ground). The angling of the first platform244and the second platform316supports the exhaust gas treatment device130both laterally and vertically, with regard to the lateral axis208and the vertical axis204, respectively.

The plurality of coil isolators146includes a first set of coil isolators246and a second set of coil isolators.FIG. 16shows a first coil isolator322, the first coil isolator322included in the first set of coil isolators246, coupled between the first platform244and a surface of a first side of the exhaust gas treatment device130. The first side of the exhaust gas treatment device is on a first bank side of the V-engine220, with respect to the centerline304. Similarly, a second coil isolator324, included in the second set of coil isolators, is coupled between the second platform316and a surface of a second side of the exhaust gas treatment device130. The second side of the exhaust gas treatment device is on a second bank side of the V-engine220, with respect to the centerline304.

A rail is coupled to each platform. Specifically, as shown inFIG. 16, a first rail248is coupled to the first platform244and a second rail320is coupled to the second platform316. Further, the first rail248and the second rail320are positioned parallel with a crankshaft of the engine. The first rail248and the second rail320are further coupled to the plurality of support legs142.

The plurality of support legs142includes a first set of support legs on the first bank214and a second set of support legs on the second bank302.FIG. 16shows a first support leg310on the first bank214, the first support leg310included in the first set of support legs, and a second support leg312on the second bank302, the second support leg312included in the second set of support legs. As shown inFIG. 16, the first support leg310is coupled to the first rail248and the second support leg312is coupled to the second rail320. The first support leg310is further coupled to a cylinder head106on the first bank214and the second support leg312is further coupled to a cylinder head106on the second bank302. Further details on the mounting of the support structure140to the engine head210and the exhaust gas treatment device130are shown inFIG. 15.

Turning toFIG. 15, a first side of the support structure, on the first bank214, is shown. Specifically,FIG. 15shows five support legs142included in the first set of support legs. The second set of support legs (not shown inFIG. 2) also includes five support legs142. In alternate embodiments, the support structure140may have more or less than ten total support legs. In one embodiment, the number of support legs is based on a number of cylinder heads. For example, in an embodiment wherein the V-engine220includes four cylinder heads106on each bank, the support structure140may include three support legs on each bank (e.g., six support legs in total). However, in other embodiments, the number of support legs may be based on other factors, such as a mass of the load placed on the support structure and/or a size of the support legs.

A first end of each support leg142in the first set of support legs is coupled to a respective cylinder head106on the first bank214. Similarly, a first end of each support leg142in the second set of support legs is coupled to a respective cylinder head106on the second bank302. Each support leg142is coupled to a side of a respective cylinder head106such that each support leg142is positioned between adjacent cylinder heads106.

FIGS. 17-18show a mounting interface between the support legs142and cylinder heads106in detail.FIG. 17is a schematic400showing the first end of each support leg142mounted to the side of a respective cylinder head106.FIG. 18is a schematic500showing a mounting bracket502of the cylinder head106. The mounting bracket502is coupled to a side504of the cylinder head106. The mounting bracket502includes holes506configurable to receive fasteners for fastening the support leg142to the mounting bracket502. Further, the mounting bracket502is positioned between holes508. The holes508are holes configurable to receive fasteners, such as bolts, for fastening the cylinder head106to the engine block212. As discussed above, each cylinder head106is individually mounted through the holes508to the engine block212. The mounting bracket502is positioned proximate to an opposite side510of an adjacent cylinder head512. Additionally, as shown inFIG. 17, each support leg142is mounted on the same side (e.g., side504shown inFIG. 18) of each cylinder head106. As such, each mounting bracket is coupled to the same side of each cylinder head106.

As shown inFIG. 17, a base402of the support leg142is coupled to the mounting bracket. Bolts404, or another type of fastener, fix the base402to the mounting bracket502at the holes506(shown inFIG. 18). As shown inFIGS. 17-18, the mounting bracket502includes two holes506, or fastening points, for mounting the support leg142to the cylinder head106. In alternate embodiments, the mounting bracket502may include more or less than two fastening points. For example, the mounting bracket502may include only one hole506and only one bolt404may fix the base402to the mounting bracket502. In another example, the mounting bracket may include three or more holes506and three or more bolts404may fix the base402of the support leg142to the mounting bracket502. The support leg142is shown in more detail atFIG. 19.

FIG. 19shows an isometric view of a single support leg142of the support structure140. The support leg142includes a first end616and a second end618. As described above, the first end616of the support leg142is coupled to a respective cylinder head. As described further below, the second end618of the support leg142is coupled to a rail of the support structure140, the rail coupled to a platform.

The support leg142includes a first segment602and a second segment604. The first segment602is coupled to the base402and a mounting face608. The base402is configurable to mount to a mounting surface. Specifically, the base402is flat and includes holes610for fastening or mounting the support leg142to a mounting surface. In the embodiments shown inFIGS. 15-18, the mounting surface is a mounting bracket of a cylinder head106. As described above with regard toFIGS. 17-18, the base402is coupled to the mounting bracket502on the side of the cylinder head106. Specifically, the bolts404pass through the holes610in the base402and the corresponding holes506in the mounting bracket502to fasten the base402to the mounting bracket502. As described above, in alternate embodiments, the base402may include more or less holes610than two, as shown. In an embodiment, the number of holes610is equal to the number of holes506. Further, the mounting face608of the support leg142is flat with a triangular shape. The mounting face608includes holes612for fastening or mounting the support leg142to one of the first rail248or the second rail320.

The second segment604is coupled to the base402and the first segment602. Specifically, a first end of the second segment604is coupled to the first segment602at a middle portion of the first segment602(e.g., between the base402and the mounting face608). A second end of the second segment604is coupled to the base402. Further, a handle614is coupled to the second segment604. The handle614may facilitate removal of the individual support leg142from its corresponding cylinder head106and from the rest of the support structure140. In an alternate embodiment, the support leg142may not include a handle614. In this case, the support leg142may still be individually removable from the support structure140and its respective cylinder head106.

Returning toFIG. 15, a second end of each support leg142is coupled to a rail. For example, as shown inFIG. 2, a second end of each support leg142of the first set of support legs is coupled to the first rail248. The first rail248is coupled to a first side of the first platform244. The first side of the first platform244is a downward-facing side which faces the engine head210. Further, a first side of each coil isolator146in the first set of coil isolators246is coupled to a second side of the first platform244. The second side of the first platform244is an upward-facing side which faces the exhaust gas treatment device130. A second side of each coil isolator146in the first set of coil isolators246is coupled to a surface of the exhaust gas treatment device130.

As shown inFIG. 15, the first platform244on the first bank214extends along a length of the engine block212. Similarly, the second platform316on the second bank302(not shown inFIG. 15) also extends along the length of the engine block212. A length of the first platform244and the second platform316is shorter than the length of the engine block212. In alternate examples, the length of the first platform244and the second platform316may be the same length as the engine block212.

Further,FIG. 15shows four coil isolators146included in the first set of coil isolators246. The second set of coil isolators (not shown inFIG. 15) also includes four coil isolators146on the opposite side of the V-engine220(e.g., second side proximate to the second bank302). The second set of coil isolators may be positioned similarly on the second platform316as the first set of coil isolators246on the first platform244, as described below.

Each coil isolator146is positioned a distance away from an adjacent coil isolator146, along a length of the first platform244. The distance between adjacent coil isolators146is not the same for all the coil isolators146. For example, as shown inFIG. 15, three coil isolators250of the first set of coil isolators246are coupled to a main body of the exhaust gas treatment device130. A fourth coil isolator252of the first set of coil isolators246is coupled to the exhaust gas treatment device130at a junction between the exhaust gas treatment device130and the exhaust passage116. As such, the three coil isolators250are positioned along the first platform244, closer to the exhaust stack216than the fourth coil isolator252. Similarly, the fourth coil isolator252is positioned along the first platform244, closer to the exhaust passage116than the three coil isolators250.

In alternate embodiments, the support structure140may have more or less than eight total coil isolators146. The number of coil isolators may be based on a size and/or length of the exhaust gas treatment device130. For example, an exhaust gas treatment device130with a longer length may include more coil isolators146on each side of the exhaust gas treatment device than an exhaust gas treatment device with a shorter length. Further, the number of coil isolators146may be based on the degree of angling of the first platform244and the second platform316. For example, angling the first platform244and the second platform316at 45 degrees allows the coil isolators146to be effective in both the vertical plane (defined with respect to the vertical axis204) and the lateral plane (defined with respect to the lateral axis208. Thus, the number of coil isolators146may be fewer when the platforms are angled at 45 degrees than if the platforms were angled at an angle greater or less than 45 degrees. In an alternate example, because the coil isolators may have different vertical and lateral stiffness, the angle allowing for the fewest coil isolators may be less than 45 degrees.

FIG. 20shows a single coil isolator146in further detail. The coil isolator146includes an elastic coil702positioned between a first plate704and a second plate706. The first plate704is mounted to one of the first platform244or the second platform316. For example, fasteners may pass through holes708on the first plate704to fix the first plate704of the coil isolator146to one of the first platform244or the second platform316. The second plate706is configured to receive a load. In the embodiments shown inFIGS. 15-16, the load is the exhaust gas treatment device130. In this embodiment, fasteners may pass through holes710on the second plate706to mount the second plate706to the surface of the exhaust gas treatment device130.

The coil isolator146may dampen vibrations transmitted by the V-engine220. For example, if the V-engine220is installed in a vehicle, the coil isolator146may resist and dampen lateral and vertical movement of the vehicle. The lateral and vertical movements are defined with respect to the lateral axis208and the vertical axis204, respectively. During engine and/or vehicle operation, the elastic coil702may compress and/or stretch to reduce the translation of vibrations from the first plate704to the second plate706. In this way, the coil isolators146may isolate the exhaust gas treatment device130from movement and vibration translated through the engine block212.

Returning toFIG. 15, the support structure140further includes a spring coil isolator on each side of the support structure140. The spring coil isolator is a type of coil isolator. As such, the coil isolators146described above may be referred to as coiled coil isolators which have a different structure than the spring coil isolators shown inFIG. 21.

As shown inFIG. 15, a first spring coil isolator260is positioned on the first platform244between the three coil isolators250and the fourth coil isolator252.FIG. 21shows a single spring coil isolator260in further detail. The spring coil isolator260includes a spring802mounted in a spring bracket804. The spring bracket804is coupled to a plate806. Further, the spring802is coupled between the spring bracket804and an arm810. The spring802may resist movement between the plate806and the arm810.

As shown inFIG. 15, the plate806of the first spring coil isolator260is coupled to the first platform244and the arm810of the first spring coil isolator260is coupled to a protruding wall262of the exhaust gas treatment device130. In this configuration, the spring coil isolator resists horizontal movement, defined with respect to the horizontal axis206, translated by the V-engine220. In this way, the spring coil isolator may dampen vibrations and/or movement in the horizontal direction, thereby isolating the exhaust gas treatment device130from the horizontal movement.

In an alternate embodiment, the support structure140may not include any spring coil isolators. In yet another embodiment, the support structure140may include more than one spring coil isolator on each side of the support structure140. Additionally, in some embodiments, the spring coil isolator may be positioned at a different location along the first platform244. For example, the protruding wall262may be positioned at a different location along the exhaust gas treatment device130(e.g., closer to the exhaust passage116or closer to the exhaust stack216). As such, the position of the spring coil isolator may change along with the altered position of the protruding wall262.

FIGS. 15-21show a non-limiting embodiment of the support structure140for the exhaust gas treatment device130of the V-engine220(or V-engine203shown inFIG. 2). As described above, in alternate embodiments, the engine head210may include more or less than six cylinder heads106on each bank of the V-engine220. As a result, the support structure140may include more or less than five support legs142on each side of the support structure140, the sides of the support structure140corresponding to the sides or banks of the V-engine220. Further, the support structure140may include any combination of isolators coupled to the platforms, the isolators including the coil isolators and the spring coil isolators. For example, the support structure140may include more or less than four coil isolators and/or more or less than one spring coil isolator on each side of the support structure140.

In this way, a support structure for an exhaust gas treatment device of an engine system may be coupled directly to an engine head of a V-engine. Specifically, the support structure may include a plurality of support legs individually mounted to a respective cylinder head of the engine head. Further, each cylinder head may be individually mounted to an engine block of the V-engine. The support structure may also include a rail coupled to support legs on each bank of the V-engine. Each rail may include a plurality of isolators which resist engine vibrations. The exhaust gas treatment device may be coupled to the coil isolators and supported vertically above the V-engine by the support structure. In this way, the exhaust gas treatment device may be supported along a length of the V-engine and isolated from engine vibrations. Further, individually mounting the support legs to respective cylinder heads creates a modular support structure and engine head, thereby allowing individual engine heads to be serviced without removing the entire support structure and exhaust gas treatment device from the engine.

As explained above, the terms “high temperature” and “low temperature” are relative, meaning that “high” temperature is a temperature higher than a “low” temperature. Conversely, a “low” temperature is a temperature lower than a “high” temperature. As used herein, the term “between,” when referring to a range of values defined by two endpoints, such as between value “X” and value “Y,” means that the range includes the stated endpoints.