Systems and methods for heating reductant

An aftertreatment system includes a reductant source, a junction, a dosing pump module, a valve assembly, and a dosing module. The reductant source stores reductant. The junction receives the reductant from the reductant source. The dosing pump module receives the reductant from the junction and selectively provides the reductant to a first conduit. The valve assembly receives the reductant from the first conduit. The valve assembly is operable between a first state, where the valve assembly provides the reductant to the junction, and a second state, where the valve assembly provides the reductant to a second conduit. The dosing module receives the reductant from the second conduit when provided by the valve assembly. The dosing module is configured to dose exhaust gases with the reductant when provided by the valve assembly.

TECHNICAL FIELD

The present application relates generally to the field of aftertreatment systems for internal combustion engines.

BACKGROUND

For internal combustion engines, such as diesel engines, nitrogen oxide (NOx) compounds may be emitted in the exhaust. To reduce NOxemissions, a selective catalytic reduction (SCR) process may be implemented to convert the NOxcompounds into more neutral compounds, such as diatomic nitrogen, water, or carbon dioxide, with the aid of a catalyst and a liquid reductant. The catalyst may be included in a catalyst chamber of an exhaust system, such as that of a vehicle or power generation unit. A liquid reductant, such as anhydrous ammonia, aqueous ammonia, diesel exhaust fluid (DEF), or aqueous urea, is typically introduced into the exhaust gas flow prior to the catalyst chamber.

To introduce the liquid reductant into the exhaust gas flow for the SCR process, an SCR system may dose or otherwise introduce the liquid reductant through a dosing pump that vaporizes or sprays the liquid reductant into an exhaust pipe of the exhaust system up-stream of the catalyst chamber. In some applications, the reductant may be subject to relatively cold temperatures, such as in cold climates or during winter, before being sprayed into the exhaust pipe. The reductant typically has a freezing point that may cause the reductant to at least partially transition from a liquid phase to a semi-solid (e.g., gel, etc.) phase when exposed to these cold temperatures. Accordingly, a mechanism is needed to heat the reductant in these applications. Some conventional engine systems provide this mechanism by routing another fluid (e.g., engine coolant, oil, heat transfer fluid, etc.) through a heat exchanger designed to heat the reductant. Other conventional engine systems utilize an electric heater designed to heat the reductant. However, each of these approaches requires additional energy input and decreases the overall efficiency of the engine system.

SUMMARY

In an embodiment, an aftertreatment system includes a reductant source, a junction, a dosing pump module, a valve assembly, and a dosing module. The reductant source stores reductant. The junction receives the reductant from the reductant source. The dosing pump module receives the reductant from the junction and selectively provides the reductant to a first conduit. The valve assembly receives the reductant from the first conduit. The valve assembly is operable between a first state, where the valve assembly provides the reductant to the junction, and a second state, where the valve assembly provides the reductant to a second conduit. The dosing module receives the reductant from the second conduit when provided by the valve assembly. The dosing module is configured to dose exhaust gases with the reductant when provided by the valve assembly.

In another embodiment, a dosing pump module includes an inlet, an outlet, an inlet chamber, a pump, and a heating mechanism. The inlet is configured to receive reductant from a reductant source. The outlet is configured to provide the reductant from the dosing pump module. The inlet chamber is configured to receive the reductant. The pump is configured to receive the reductant from the inlet chamber and to provide the reductant to the outlet. The heating mechanism is positioned proximate to the inlet chamber. The heating mechanism is configured to heat the reductant within the inlet chamber.

In another embodiment, a dosing pump module includes an inlet, an outlet, an inlet chamber, a heating mechanism, a chamber, a filter, and a cap. The inlet is configured to receive reductant from a reductant source. The outlet is configured to provide the reductant from the dosing pump module. The heating mechanism is positioned proximate to the inlet chamber. The heating mechanism is configured to heat the reductant within the inlet chamber. The chamber is configured to receive the reductant from the inlet. The filter is positioned within the chamber. The cap is configured to selectively encapsulate the chamber such that the filter is positioned within the chamber.

DETAILED DESCRIPTION

Following below are more detailed descriptions of various concepts related to, and implementations of, methods, apparatuses, and systems for heating reductant. The various concepts introduced above and discussed in greater detail below may be implemented in any of numerous ways, as the described concepts are not limited to any particular manner of implementation. Examples of specific implementations and applications are provided primarily for illustrative purposes.

Internal combustion engines (e.g., diesel internal combustion engines, etc.) produce exhaust gases that are often treated within an aftertreatment system. This treatment often includes treating (e.g., dosing, etc.) the exhaust gases with a reductant. The reductant is provided to the exhaust gases through the use of a pump. In some applications, such as when the internal combustion engine operates in a relatively cold environment, the reductant may tend to gel or solidify. It is important to remove gelled or solidified reductant prior to circulation through the reductant to the pump. Accordingly, the reductant needs to be heated in these applications. Conventionally, the reductant is heated by a heat exchanger or separate electric heater positioned to heat the reductant in a tank or along a reductant line. However, conventional approaches require costly components, the consumption of a relatively large amount of auxiliary energy, and are inefficient because the heated reductant is immediately transmitted into the exhaust gases.

Implementations described herein relate to a reductant delivery system that includes a dosing pump module that heats reductant within the dosing pump module and a valve assembly that selectively recirculates heated reductant upstream of the dosing pump module. The dosing pump module heats the reductant through the use of a heating mechanism that is controlled by a controller. The valve assembly is controlled by the controller to provide heated reductant from the dosing pump module to at least one of a location upstream of the dosing pump module and a dosing module for being provided to exhaust gases. In this way, the dosing pump module can be self-sustaining because the dosing pump module may not require any other mechanism for heating reductant other than the recirculated reductant which was previously heated by the dosing pump module.

The reductant delivery system described herein decreases costs compared to conventional systems because a heat exchanger or separate electrical heater is not utilized for heating the reductant or, if a heat exchanger or separate electrical heater is utilized, the auxiliary energy consumption thereof is significantly reduced compared to conventional systems. The reductant delivery system described herein is able to eliminate gelled or solidified reductant with the use of less, if any, of the auxiliary energy because of the selective recirculation of the heated reductant. Additionally, the incorporation of a heating mechanism directly within the dosing pump module simplifies the reductant delivery system compared to conventional systems. As a result, the reductant delivery system may be significantly less expensive than conventional systems.

II. Overview of Aftertreatment System

FIG. 1depicts an aftertreatment system100having an example reductant delivery system110for an exhaust system190. The exhaust system190receives exhaust gases from an internal combustion engine (e.g., diesel internal combustion engine, etc.). The aftertreatment system100includes a particulate filter (e.g., a diesel particulate filter (DPF)102), the reductant delivery system110, a decomposition chamber104(e.g., reactor, etc.), and a SCR catalyst106(e.g., a chamber containing a catalyst). The aftertreatment system100may also include a sensor150.

The DPF102is configured to remove particulate matter, such as soot, from exhaust gas flowing in the exhaust system190. The DPF102includes an inlet, where the exhaust gas is received (e.g., from an engine manifold, etc.), and an outlet, where the exhaust gas exits after having particulate matter substantially filtered from the exhaust gas and/or converting the particulate matter into carbon dioxide. In some implementations, the DPF102may be omitted.

The decomposition chamber104is configured to convert a reductant, such as urea or DEF, into ammonia. The decomposition chamber104includes a reductant delivery system110having a dosing module112(e.g., doser, etc.) configured to dose the reductant into the decomposition chamber104. In some implementations, the reductant is injected upstream of the SCR catalyst106. The reductant droplets then undergo the processes of evaporation, thermolysis, and hydrolysis to form gaseous ammonia within the exhaust system190. The decomposition chamber104includes an inlet in fluid communication with the DPF102to receive the exhaust gas containing NOxemissions and an outlet for the exhaust gas, NOxemissions, ammonia, and/or reductant to flow to the SCR catalyst106.

The decomposition chamber104includes the dosing module112mounted to the decomposition chamber104such that the dosing module112may dose the reductant into the exhaust gases flowing in the exhaust system190. The dosing module112may include an insulator114interposed between a portion of the dosing module112and the portion of the decomposition chamber104on which the dosing module112is mounted. The dosing module112is fluidly coupled to one or more reductant sources116(e.g., tanks, vessels, etc.). In some implementations, a pump118may be used to pressurize the reductant from the reductant sources116for delivery to the dosing module112.

The dosing module112is also fluidly coupled to one or more air sources115. For example, the air sources115may be an air intake or air storage device (e.g., tank, etc.). A pump117(e.g., lift pump, etc.) is used to pressurize the air from the air sources115for delivery to the dosing module112(e.g., via pressurized conduits, etc.). The dosing module112mixes the air from the air sources115and the reductant from the reductant sources116and provides the air-reductant mixture into the decomposition chamber104.

The dosing module112, the pump117, and the pump118are also electrically or communicatively coupled to a controller120. The controller120is configured to control the dosing module112to dose the air-reductant mixture into the decomposition chamber104. The controller120may also be configured to control the pump117and/or the pump118. For example, the controller120may control the pump117and the pump118to obtain a target mixture of air and reductant that is provided to the decomposition chamber104. In some implementations, the pump117and the air sources115may be omitted. In these implementations, the dosing module112does not receive pressurized air.

The controller120may include a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), etc., or combinations thereof. The controller120may include memory, which may include, but is not limited to, electronic, optical, magnetic, or any other storage or transmission device capable of providing a processor, ASIC, FPGA, etc. with program instructions. The memory may include a memory chip, Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), flash memory, or any other suitable memory from which the controller120can read instructions. The instructions may include code from any suitable programming language.

The SCR catalyst106is configured to assist in the reduction of NOxemissions by accelerating a NOxreduction process between the ammonia and the NOxof the exhaust gas into diatomic nitrogen, water, and/or carbon dioxide. The SCR catalyst106includes an inlet in fluid communication with the decomposition chamber104from which exhaust gas and reductant are received and an outlet in fluid communication with an end of the exhaust system190.

The exhaust system190may further include an oxidation catalyst (for example a diesel oxidation catalyst (DOC)) in fluid communication with the exhaust system190(e.g., downstream of the SCR catalyst106or upstream of the DPF102) to oxidize hydrocarbons and carbon monoxide in the exhaust gas.

In some implementations, the DPF102may be positioned downstream of the decomposition chamber104. For instance, the DPF102and the SCR catalyst106may be combined into a single unit. In some implementations, the dosing module112may instead be positioned downstream of a turbocharger or upstream of a turbocharger.

The sensor150may be coupled to the exhaust system190to detect a condition of the exhaust gas flowing through the exhaust system190. In some implementations, the sensor150may have a portion disposed within the exhaust system190; for example, a tip of the sensor150may extend into a portion of the exhaust system190. In other implementations, the sensor150may receive exhaust gas through another conduit, such as one or more sample pipes extending from the exhaust system190. While the sensor150is depicted as positioned downstream of the SCR catalyst106, it should be understood that the sensor150may be positioned at any other position of the exhaust system190, including upstream of the DPF102, within the DPF102, between the DPF102and the decomposition chamber104, within the decomposition chamber104, between the decomposition chamber104and the SCR catalyst106, within the SCR catalyst106, or downstream of the SCR catalyst106. In addition, two or more sensors150may be utilized for detecting a condition of the exhaust gas, such as two, three, four, five, or six sensors150with each sensor150located at one of the foregoing positions of the exhaust system190. In some implementations, the sensors150may be omitted.

III. Example Dosing Pump Module

FIG. 2depicts a dosing pump module200according to an example embodiment. The dosing pump module200receives reductant (e.g., DEF, urea, AdBlue®, etc.) from a source (e.g., tank, etc.) through an inlet202and provides the reductant into an exhaust conduit (e.g., exhaust pipe, etc.) for treating exhaust gases through an outlet204.

The inlet202provides the reductant to a first channel206that provides the reductant into a chamber208having a filter210. Within the chamber208, the reductant is filtered (e.g., strained, etc.) by the filter210. After being filtered, the reductant flows into a second channel212where the reductant is routed to a pump214. The pump214includes an inlet chamber215. Reductant collects within the inlet chamber215prior to being provided to a pumping mechanism (e.g., ram, turbine, screw drive, etc.) within the pump214. The pump214then propels the reductant from the inlet chamber215through the outlet204. The pump214may be a linear pump, a solenoid pump, or other similar pump.

The inlet202is in fluid communication with the first channel206, which is in fluid communication with the chamber208, which is in fluid communication with the second channel212, which is in fluid communication with the pump214, which is in fluid communication with the outlet204. The pump214is operational between a first state (e.g., on, enabled, powered, operational, etc.), in which the pump214provides reductant to the outlet204, and a second state (e.g., off, disabled, unpowered, non-operational, etc.), in which the pump214does not provide reductant to the outlet204.

The dosing pump module200also includes a housing216. The housing216contains the first channel206, the second channel212, and the pump214. In various embodiments, the dosing pump module200also includes a filter mount217. The filter mount217extends into the chamber208. The filter210is mounted on the filter mount217such that the filter210is secured within the chamber208. For example, the filter mount217may extend through a central aperture of the filter210.

The first channel206, the second channel212, and the chamber208may be drilled into the housing216. During assembly of the dosing pump module200, the housing216may include a cavity into which the pump214is placed. This cavity may be filed with material (e.g., sealant, etc.) such that the pump214is fluidly sealed within the housing216from outside fluid. Prior to filling this cavity, a hole may be drilled from this cavity into the chamber208. This hole may receive the filter mount217. By filling the cavity and covering the pump214, the filter mount217is secured within the housing216.

The inlet202is coupled to the housing216such that a fluid-tight seal is created between the inlet202and the housing216. The outlet204is also coupled to the housing216such that a fluid tight seal is created between the outlet204and the housing216. The housing216includes a threaded portion218extending from the housing216. The threaded portion218includes at least a portion of the chamber208positioned therein. The threaded portion218interfaces with a cap220. The cap220provides access to the filter210such that the filter210can be, for example, replaced, cleaned, or otherwise serviced. The threaded interface between the cap220and the threaded portion218facilitates the formation of a fluid-tight seal therebetween. Further, the cap220may be configured such that the cap220can be removed without the use of tools (e.g., tool-less, etc.). For example, the cap220may be a “spin-on” cap.

The dosing pump module200may be installed in various applications such as vehicles (e.g., trucks, cars, commercial vehicles, construction vehicles, emergency vehicles, etc.), maritime vessels (e.g., ships, barges, boats, cruisers, etc.), and generators (e.g., standby generators, industrial generators, diesel generators, gensets, etc.). In an example application, the dosing pump module200is installed in a diesel vehicle that may be subject to various environmental (e.g., ambient, etc.) temperatures. For example, the diesel vehicle may operate in the summer and in the winter.

The dosing pump module200is designed to operate with the reductant being supplied to the dosing pump module200at various temperatures. When the reductant supplied to the dosing pump module200is cold, such as may occur when the dosing pump module200is operated in the winter, the reductant may tend to gel or otherwise solidify. For example, reductant may tend to gel at temperatures less than 262.15 degrees Kelvin (e.g., negative eleven degrees Celsius, etc.). It is undesirable to provide solidified or partially solidified reductant through the pump214to the outlet204because performance (e.g., efficiency, longevity, etc.) of the pump214may be negatively impacted. Therefore, the reductant should be heated (e.g., thawed, etc.) before the reductant can be provided through the pump214to the outlet204.

In order to accommodate use of the dosing pump module200in cold weather where reductant may tend to solidify, the pump214incorporates a heating mechanism222. The heating mechanism222functions to heat reductant within the inlet chamber215of the pump214, regardless of whether the pump214is in the first state or the second state. In other words, the heating mechanism222may heat the reductant that collects within the inlet chamber215when the pump214is not providing the reductant to the outlet204(e.g., in the second state, etc.) and when the pump214is providing the reductant to the outlet204(e.g., in the first state, etc.). The heating mechanism222may include, for example, a series of resistance heating elements. The series of resistance heating elements may be positioned around the inlet chamber215. The heating mechanism222may also include a heat exchanger that provides heat from a thermal transfer fluid to the reductant within the inlet chamber215.

Conventional dosing systems may heat reductant a variety of ways. For example, conventional dosing systems may heat a reductant tank to cause the reductant therein to be heated. Conventional dosing systems may also cause the reductant to be heated through the use of a heat exchanger which passes heat from a hot fluid to the reductant. The hot fluid may be, for example, an engine coolant, lubricant, or dedicated thermal transfer fluid (e.g., within a dedicated thermal transfer loop circulating between a heat source and the heat exchanger, etc.). Conventional dosing systems may also utilize electric heaters that transform electrical energy (e.g., from a battery, from an alternator, etc.) into heat. However, conventional dosing systems do not heat the reductant directly within a pump.

In various embodiments, the dosing pump module200is implemented along with some conventional mechanisms for heating the reductant. In this way, the dosing pump module200may complement a conventional dosing system by directly heating the reductant within the dosing pump module200while the reductant supplied to the dosing pump module200is heated by the conventional dosing system. With this arrangement, both the conventional dosing system and the dosing pump module200share the task of heating the reductant. This may increase efficiency of the an internal combustion engine associated with the dosing pump module200. The dosing pump module200selectively recirculates the reductant after it has been heated in order to utilize heat that would otherwise be wasted. Because conventional systems do not recirculate reductant, they are incapable of achieving the same efficiency and advantages of the dosing pump module200.

IV. Example Aftertreatment System Including an Example Dosing Module

FIG. 3illustrates an aftertreatment system300including a reductant delivery system301having the dosing pump module200. The aftertreatment system300includes some of the same components as the aftertreatment system100previously described, such as the reductant delivery system301. Where the components are the same, their operation will not be repeated here.

The aftertreatment system300includes a first conduit302that provides reductant from the reductant sources116to a junction304. The junction304is fluidly communicable with the first conduit302, a second conduit306, and a third conduit308. The junction304facilitates the exchange of fluid between any of the first conduit302, the second conduit306, and the third conduit308. In some embodiments, the third conduit308incorporates a check valve positioned proximate to the junction304. This check valve is configured to (e.g., structured to, etc.) prevent the flow of reductant from the first conduit302into the third conduit308.

The second conduit306provides the reductant to the dosing pump module200. The dosing pump module200selectively provides the reductant to a fourth conduit310. A valve assembly312receives the reductant from the fourth conduit310and selectively provides the reductant to a fifth conduit314and/or the third conduit308. The fifth conduit314selectively provides the reductant to the dosing module112which provides the reductant to the decomposition chamber104.

The valve assembly312includes a controllable valve and a check valve (e.g., no-return valve, etc.). The controllable valve included within the valve assembly312may be, for example, an orifice valve, a ball valve (e.g., electronically controllable ball valve, etc.), a bimetallic valve, a solenoid valve, and other similar valves. The check valve included within the valve assembly312functions to prevent backflow of the reductant into the fourth conduit310, such as from the third conduit308or the fifth conduit314.

The valve assembly312is operable between a first state (e.g., full recirculation state, mode, setting, etc.), where the valve assembly312provides the reductant to only the third conduit308, a second state (e.g., full dosing state, mode, setting, etc.), where the valve assembly312provides the reductant to only the fifth conduit314, and a third state (e.g., partial recirculation state, mode, setting, etc.), where the valve assembly312provides the reductant to both the third conduit308and the fifth conduit314. The dosing pump module200functions to increase the temperature of the reductant from a first temperature (e.g., two-hundred and seventy-three degrees Kelvin, zero degrees Celsius, etc.) within the second conduit306to a second temperature (e.g., two-hundred and seventy-eight degrees Kelvin, five degrees Celsius, etc.), greater than the first temperature, within the fourth conduit310.

When the reductant is provided by the valve assembly312to the third conduit308, the reductant is recirculated to the junction304where it is combined with the reductant from the reductant sources116. This combination of the reductant causes an increase in temperature of the reductant provided from the reductant sources116because the reductant provided from the third conduit308had been previously heated within the dosing pump module200by the heating mechanism222. The reductant provided from the third conduit308has a first temperature (e.g., two-hundred and seventy-eight degrees Kelvin, five degrees Celsius, etc.), the reductant within the first conduit302, which is provided to the junction304, has a second temperature (e.g., two-hundred and seventy-three degrees Kelvin, zero degrees Celsius, etc.), less than first temperature, and the reductant within the second conduit306, which is provided to the dosing pump module200, has a third temperature (e.g., two-hundred and seventy-six degrees Kelvin, three degrees Celsius, etc.), greater than the second temperature and less than the first temperature.

When the valve assembly312is in the third state, a first portion of the reductant is provided to the third conduit308, for recirculation to the junction304thereby causing heating of the reductant from the reductant sources116, and a second portion (e.g., remaining portion, etc.) of the reductant is provided to the fifth conduit314, for use by the dosing module112(e.g., to dose the decomposition chamber104, etc.). The ratio of the first portion of the reductant to the second portion of the reductant is directly related to the difference in temperature between the temperature of the reductant within the first conduit302to the temperature of the reductant within the second conduit306. For example, the greater the ratio of the first portion of the reductant to the second portion of the reductant (e.g., more of the reductant is provided to the third conduit308than to the fifth conduit314, etc.), the greater the increase in temperature between the temperature of the reductant within the first conduit302to the temperature of the reductant within the second conduit306.

Another factor directly related to the difference in temperature between the temperature of the reductant within the first conduit302to the temperature of the reductant within the second conduit306is the amount of heating provided by the heating mechanism222to the reductant within the inlet chamber215. The amount of heating provided by the heating mechanism222may be selected based on a temperature of the reductant at a location such as within the inlet chamber215, within the first conduit302, within the junction304, within the second conduit306, and within the reductant sources116. The temperature of the reductant may be determined by a sensor, such as the sensor150which is shown inFIG. 3as measuring the temperature of the reductant within the reductant sources116. The controller120may compare the temperature from the sensor150to a target temperature to determine the amount of heating to be provided by the heating mechanism122. The target temperature may be based on requirements of the dosing pump module200, characteristics (e.g., brand, composition, etc.) of the reductant, and operating conditions of an internal combustion engine associated with the aftertreatment system300, and other similar conditions.

FIG. 4illustrates a difference between the temperature of the reductant within the fourth conduit310(labeled as “Outlet”) and the temperature of the reductant within the second conduit306(labeled as “Inlet”). The amount of heating provided by the heating mechanism222is directly related to the difference between the two temperatures shown inFIG. 4for each instance in time.

In addition to the dosing module112and the sensor150, the controller120is communicatively coupled to the dosing pump module200and the valve assembly312. With regard to the dosing pump module200, the controller120is communicatively coupled to the pump214and the heating mechanism222. The controller120may, for example, control a speed of the pump214(e.g., to produce a target flow rate of the reductant into the fourth conduit310, etc.) and control an amount of heating provided by the heating mechanism222(e.g., by controlling an amount of electrical energy provided to the heating mechanism222, etc.). By controlling the speed of the pump214, the controller120can increase heat transfer between the reductant from the third conduit308to the reductant from the first conduit302as well as between the heating mechanism222and the reductant within the inlet chamber215. With regard to the valve assembly312, the controller120may, for example, control a state of the valve assembly312thereby dictating an amount of the reductant, if any, that is provided to the third conduit308and the fifth conduit314. Specifically, the controller120may control a position of an electronically controllable valve within the valve assembly312.

In an example operation, the controller120receives sensor data from the sensor150, the sensor data related to the temperature of the reductant at a location within the reductant delivery system301. The controller120then compares the temperature to a threshold to determine if the temperature is less than the threshold. If the controller120determines that the temperature is less than the threshold, the controller120determines that the reductant needs to be heated.

The controller120is capable of heating (e.g., configured to heat, structured to heat, etc.) the reductant by varying the amount of heating provided by the heating mechanism222, by controlling the valve assembly312to vary the ratio of the portion of the reductant provided to the third conduit308to the portion of the reductant provided to the fifth conduit314, and by controlling a speed of the pump214.

Depending on the operating condition (e.g., non-operational, pre-start, start-up, idle, high-load, cooldown, etc.) of an internal combustion engine associated with the aftertreatment system300, the controller120may provide heating to the reductant in different ways. The threshold temperature, against which the controller120compares the temperature determined from the sensor data from the sensor105, may be different depending on the operating condition of the internal combustion engine associated with the aftertreatment system300.

V. Example Operation of a Reductant Delivery System Including the Dosing Pump Module

The following is a simplified overview of several example operations of the reductant delivery system301including the dosing pump module200and other components of the aftertreatment system300. These examples are not limiting in nature or scope and are provided for explanation only. In these examples, the reductant within the reductant sources116is relatively cold, and therefore tends to gel or solidify. Depending on the operating condition of the internal combustion engine, the reductant delivery system301functions differently to ensure that reductant is provided to the dosing module112when necessary and to ensure that the pump214is not negatively impacted by the reductant.

In the non-operational mode, the internal combustion engine is not running and therefore reductant does not need to be provided to the dosing module112. Therefore, the controller120may control the valve assembly312such that all of the reductant is provided to the third conduit308. The threshold may be relatively low because the reductant may only need to be only heated enough to ensure that the pump214is not negatively impacted by the reductant. The heating mechanism222may only be required to provide a relatively small amount of heat to the reductant within the inlet chamber215. The speed of the pump214, as controlled by the controller120, may be relatively low because reductant does not need to be provided to the dosing module112. For example, the speed of the pump214may be selected to be sufficient such that the reductant does not tend to gel outside of the dosing pump module200, such as within the third conduit308or the first conduit302.

In the pre-start mode, the internal combustion engine is not running and therefore reductant does not need to be provided to the dosing module112. Therefore, the controller120may control the valve assembly312such that all of the reductant is provided to the third conduit308. The pre-start mode may be initiated when operation of the internal combustion engine is imminent, such as when an operator initiates a start-up sequence. Therefore, while reductant is not currently being provided to the dosing module112, the reductant delivery system301has to immediately prepare for providing the reductant to the dosing module112. The threshold may be higher than for the non-operational mode because the reductant will soon need to be circulated to the dosing module112. The heating mechanism222may be required to provide more heat to the reductant within the inlet chamber215than provided in the non-operational mode. The speed of the pump214, as controlled by the controller120, may be greater than in the non-operational mode because reductant will soon be provided to the dosing module112.

In the start-up mode, the internal combustion engine is running and therefore some reductant needs to be provided to the dosing module112. However, the reductant entering the dosing pump module200also needs to be heated. Therefore, the controller120may control the valve assembly312such that a smaller portion (e.g., fifteen percent, etc.) of the reductant is provided to the fifth conduit314and a larger portion (e.g., eighty-five percent, etc.) of the reductant is provided to the third conduit308. The start-up mode may be initiated when an operator turns a key. The threshold may be higher than for the pre-start mode because increasing the fluidity of the reductant (e.g., reducing or eliminating any gelling within the reductant, etc.) is important. The heating mechanism222may be required to provide more heat to the reductant within the inlet chamber215than provided in the pre-start mode. The speed of the pump214, as controlled by the controller120, may be greater than in the pre-start mode because the reductant is being provided to the dosing module112.

In the idle mode, the internal combustion engine is running and therefore some reductant needs to be provided to the dosing module112. However, the reductant entering the dosing pump module200may also need to be heated. Therefore, the controller120may control the valve assembly312such that a larger portion (e.g., sixty-five percent, etc.) of the reductant is provided to the fifth conduit314and a smaller portion (e.g., thirty-five percent, etc.) of the reductant is provided to the third conduit308. The idle mode may be initiated when the internal combustion engine is running under a no-load condition. The threshold may be lower than for the start-up mode because increasing the fluidity of the reductant (e.g., reducing or eliminating any gelling within the reductant, etc.) is important. The heating mechanism222may be required to provide less heat to the reductant within the inlet chamber215than provided in the start-up mode. The speed of the pump214, as controlled by the controller120, may be less than in the pre-start mode because less exhaust gases are provided from the internal combustion engine in the idle mode than in the start-up mode.

In the high-load mode, the internal combustion engine is running and therefore some reductant needs to be provided to the dosing module112. However, the reductant entering the dosing pump module200may also need to be heated. Therefore, the controller120may control the valve assembly312such that a larger portion (e.g., ninety percent, etc.) of the reductant is provided to the fifth conduit314and a smaller portion (e.g., ten percent, etc.) of the reductant is provided to the third conduit308. In some applications, the controller120may control the valve assembly312such that all of the reductant is provided to the fifth conduit314and none of the reductant is provided to the third conduit308. The high-load mode may be initiated when the internal combustion engine is running under a high-load condition, such as when operating near maximum speed or power. The threshold may be lower than for the start-up mode because increasing the fluidity of the reductant (e.g., reducing or eliminating any gelling within the reductant, etc.) is important. The heating mechanism222may be required to provide less heat to the reductant within the inlet chamber215than provided in the start-up mode. The speed of the pump214, as controlled by the controller120, may be greater than in the idle mode because more exhaust gases are provided from the internal combustion engine in the high-load mode than in the idle mode.

In the cooldown mode, the internal combustion engine is running and therefore some reductant needs to be provided to the dosing module112. However, the reductant entering the dosing pump module200may also need to be heated. Therefore, the controller120may control the valve assembly312such that a larger portion (e.g., fifty-five percent, etc.) of the reductant is provided to the fifth conduit314and a smaller portion (e.g., forty-five percent, etc.) of the reductant is provided to the third conduit308. The cooldown mode may be initiated when shutdown of the internal combustion engine is imminent, such as when an operator turns off the internal combustion engine. The portion of the reductant that is provided to the fifth conduit314may be greater for the cooldown mode than for the high-load mode because increasing the fluidity of the reductant (e.g., reducing or eliminating any gelling within the reductant, etc.) is less important. The heating mechanism222may be required to provide less heat to the reductant within the inlet chamber215than provided in the start-up mode. The speed of the pump214, as controlled by the controller120, may be less than in the high-load mode because less exhaust gasses are provided from the internal combustion engine in the cooldown mode than in the high-load mode.

TABLE 1Characteristics of the Reductant Delivery System for Various Operational Modesof an Internal Combustion Engine Associated with the Reductant Delivery System.Ratio of the Portion of the ReductantHeating ProvidedProvided to the Third Conduit 308 to theOperationalby the HeatingSpeed of thePortion of the Reductant Provided to theModeMechanism 222Pump 214Fifth Conduit 314Non-operationalLowLowAll the reductant is provided to the thirdconduit 308Pre-startMediumMediumAll the reductant is provided to the thirdconduit 308Start-upHighHighHighIdleMediumMediumMediumHigh-loadMediumHighLow; or all of the reductant is provided tothe fifth conduit 314CooldownLowMediumMedium
VI. Construction of Example Embodiments

In addition to the example reductant delivery system shown inFIG. 3, it is understood that various modifications are possible. For example, conventional heat exchangers (e.g., engine coolant heat exchangers, engine oil heat exchangers, etc.) or electrical heaters may be incorporated at various positions within the reductant delivery system to compliment the heating mechanism222in heating the reductant. These complimentary heat sources may be communicatively coupled to the controller120and controlled thereby. For example, an electrical heater may be positioned along the first conduit302that provides heat to the reductant therein. This electrical heater may be controlled to provide varying amounts of heat to the reductant depending on an operating condition of the internal combustion engine.

While not shown, the junction304may be configured to facilitate mixing and maximize transfer of heat to the reductant from the first conduit302. For example, the junction304may incorporate a mixing device (e.g., perforated plate, coalescing device, turbine, etc.) designed to intermix the reductant from the third conduit308with the reductant from the first conduit302.

While not shown, it is understood that the dosing pump module200may be implemented in various systems similar to the aftertreatment system300. For example, the dosing pump module200may be implemented in a fuel delivery system that provides fuel (e.g., diesel fuel, etc.) to an internal combustion engine. In a fuel delivery system, the dosing pump module200may function to prevent gelling or other solidification of the fuel provided to a fuel injector. Other systems, such as turbocharged systems, liquid filtration systems, exhaust gas recirculation systems, hydraulic systems, and other similar systems may also implement the dosing pump module200in a similar capacity to those described herein.

The terms “coupled,” “connected,” and the like, as used herein, mean the joining of two components directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or movable (e.g., removable or releasable). Such joining may be achieved with the two components or the two components and any additional intermediate components being integrally formed as a single unitary body with one another, with the two components, or with the two components and any additional intermediate components being attached to one another.

The terms “fluidly coupled,” “in fluid communication,” and the like, as used herein, mean the two components or objects have a pathway formed between the two components or objects in which a fluid (e.g., exhaust, water, air, gaseous reductant, gaseous ammonia, etc.) may flow, either with or without intervening components or objects. Examples of fluid couplings or configurations for enabling fluid communication may include piping, channels, or any other suitable components for enabling the flow of a fluid from one component or object to another. As described herein, “preventing” gelling of reductant should be interpreted as potentially allowing for de minimus gelling (e.g., less than one percent, etc.) of reductant.

It is important to note that the construction and arrangement of the system shown in the various example implementations is illustrative only and not restrictive in character. All changes and modifications that come within the spirit and/or scope of the described implementations are desired to be protected. It should be understood that some features may not be necessary, and implementations lacking the various features may be contemplated as within the scope of the application, the scope being defined by the claims that follow. When the language “a portion” is used, the item can include a portion and/or the entire item, unless specifically stated to the contrary.