Systems for methanol vaporization

An exhaust heater system includes an exhaust heater and an air supply tube disposed within the exhaust heater. Relatively hot exhaust gas from an engine is directed into the exhaust heater, whereby heat from the exhaust heats the interior of the air supply tube. The heat partially vaporizes liquid methanol injected into the air supply tube. To control the amount of heating, the exhaust can be directed to the air supply tube as well as an exhaust bypass, whereby exhaust directed to the exhaust bypass does not heat the interior of the air supply tube.

TECHNICAL FIELD

The present disclosure relates generally to operating an internal combustion engine, and more particularly, to injecting methanol into a heated intake air stream to vaporize at least a portion of the methanol, whereby the air stream is heated using exhaust heat of the internal combustion engine.

BACKGROUND

The internal combustion engine is widely used in various industries. Internal combustion engines can operate on a variety of different liquid fuels, gaseous fuels, and various blends. Spark-ignited engines employ an electrical spark to initiate combustion of fuel and air, whereas compression ignition engines typically compress gases in a cylinder to an autoignition threshold such that ignition of fuel begins without requiring a spark. Further, in pilot-ignited applications, including dual fuel applications, a mixture of a gaseous fuel, such as natural gas and air, is delivered into a cylinder and ignition is triggered using a relatively small direct injection of a compression ignition fuel which autoignites to trigger ignition of the relatively larger main charge.

As part of the effort to improve the efficiency of these engines, researchers have explored various types of alternate fuel mixtures, including alcohol fuels like methanol. In some examples, methanol is directly injected into an engine cylinder and the methanol is ignited with a pilot fuel or a spark. The use of methanol can provide various benefits over other alternate fuel additives. For example, methanol has relatively low production costs and can be less expensive to produce relative to other alternative fuels. Further, the availability of methanol can be greater than other sources of alternate fuel additives because methanol can be produced in a variety of ways using materials ranging from natural gas to coal. Further, methanol is relatively safe to use, store, and transport because methanol has a relatively low risk of flammability.

However, methanol is characterized by a relatively high latent heat of vaporization which can be problematic in some situations. For example, when injecting methanol into an intake system, the relatively high latent heat of vaporization can result in a portion of the methanol forming as a film on the interior walls of the intake system. Liquid methanol that enters a combustion chamber affects the performance of the engine. For example, liquid methanol can cause random perturbations (or deviations) in the conditions of a combustion cylinder, increasing cycle-to-cycle variations and decreasing combustion stability. Further liquid methanol can corrosively attack the interior surfaces of the cylinders, pistons, and other components involved in the combustion cycle inside the engine.

Some efforts have been made to ameliorate this issue. For example, Chinese Patent Application No. CN110816800A to Long Wuqiang et al. (“the '800 application”) describes a system configured to raise the temperature of methanol stored in a storage tank. The system of the '800 application includes a methanol reformer and a vaporizer. The vaporizer superheats the methanol prior to entering the methanol reformer. However, the system described in the '800 application is not directed to internal combustion engines that use methanol as a component of fuel. As a result, the system set forth in the '800 does not solve issues relating to the above-noted issues relating to the use of methanol as a fuel.

Examples of the present disclosure are directed to overcoming deficiencies of such systems.

SUMMARY

In an aspect of the present disclosure, a method of operating an engine includes receiving air into a heating section of an intake manifold, injecting methanol into the heating section to form a methanol/air mixture, vaporizing at least a portion of the methanol in the methanol/air mixture by directing exhaust into an exhaust heater, wherein the heating section is at least partially internally disposed within the exhaust heater allowing for heat from the exhaust to heat the heating section, introducing a fuel and the methanol/air mixture into a combustion cylinder, and causing the fuel and the methanol/air mixture in the combustion cylinder to ignite.

In another aspect of the present disclosure, an exhaust heater system includes an exhaust tube having an exhaust tube outer surface, an exhaust tube inner surface, and a longitudinal central axis extending substantially centrally through the exhaust tube, the exhaust tube inner surface defining an interior space of the exhaust tube, an air supply tube disposed within the interior space of the exhaust tube, the air supply tube having an air supply tube outer surface and an air supply tube inner surface, a methanol injector configured to inject methanol into the air supply tube, a turbine configured to receive exhaust from an engine and direct the exhaust to the exhaust tube, and a compressor powered by turbine, the compressor configured to direct compressed air into the air supply tube, wherein heat from the exhaust in the exhaust tube heats and vaporizes at least a portion of the methanol injected into the air supply tube

In a still further aspect of the present disclosure, an internal combustion engine fuel system includes an exhaust heater system comprising an exhaust tube having an exhaust tube outer surface, an exhaust tube inner surface, and a longitudinal central axis extending substantially centrally through the exhaust tube, the exhaust tube inner surface defining an interior space of the exhaust tube, an air supply tube disposed within the interior space of the exhaust tube, the air supply tube having an air supply tube outer surface and an air supply tube inner surface, a methanol injector configured to inject methanol into the air supply tube, a turbine configured to receive exhaust from an engine and direct the exhaust to the exhaust tube, and a compressor powered by turbine, the compressor configured to direct compressed air into the air supply tube to form a methanol/air mixture in the air supply tube, wherein heat from the exhaust in the exhaust tube heats and vaporizes at least a portion of the methanol injected into the air supply tube. The internal combustion engine fuel system further includes a fuel injector for injecting a fuel into the methanol/air mixture.

DETAILED DESCRIPTION

Wherever possible, the same reference numbers will be used throughout the drawings to refer to same or like parts. Referring toFIG.1, there is shown an internal combustion engine system100, in accordance with an example of the present disclosure. In the example shown inFIG.1, the internal combustion engine system100includes an internal combustion engine102having an engine housing104. The internal combustion engine102further includes a first piston106A and a second piston106B. The first piston106A is disposed within an interior volume108A of a first combustion cylinder110A. The interior volume108A is defined by an inner surface112A of the first combustion cylinder110A. The second piston106B is disposed within an interior volume108B of a second combustion cylinder110B. The interior volume108B is defined by an inner surface112B of the second combustion cylinder110B. The first piston106A is movable between a first top dead center position114A and first bottom dead center position116A. The second piston106B is movable between a second top dead center position114B and second bottom dead center position116B. The first piston106A and the second piston106B move between the first top dead center position114A and the first bottom dead center position116A, and the second top dead center position114B and the second bottom dead center position116B, respectively, to rotate a crankshaft120in a generally conventional manner.

The internal combustion engine system100further includes an intake manifold122and an exhaust manifold124. The intake manifold122supplies a methanol/air mixture126comprising methanol158and air130. A compression ignition fuel128, such as diesel fuel, is injected into the interior volume108A of the first combustion cylinder110A using direct injector154A and the interior volume108B of the second combustion cylinder110B using direct injector154B. The compression of the methanol/air mixture126and the fuel128causes the fuel128to autoignite and subsequently the methanol/air mixture126to ignite, forcing the first piston106A from the first top dead center position114A to the first bottom dead center position116A position and the second piston106B from the second top dead center position114B to the second bottom dead center position116B._It should be noted that the presently disclosed subject matter is not limited to any particular type of fuel. For example, if the internal combustion engine system100is a gasoline engine, the fuel128comprises one or more octanes of gasoline. It should be noted that the fuel128may additionally include fuel additives and the like.

The air130is introduced into a first air intake section134of the internal combustion engine system100at air intake136. The air130is compressed by a turbo140. The turbo140includes a compressor142and a turbine144. The turbine144receives exhaust146from the exhaust manifold124, through exhaust intake148, and into the turbine144. The exhaust146includes bi-products of the combustion process taking place within the internal combustion engine system100(explained in more detail, below), and thus, is at a relative high pressure and temperature as compared to the air130. The pressure (and temperature) of the exhaust146impinges on the blades of the turbine144, thereby causing the blades, and a shaft147of the turbo140connected thereto, to rotate in a conventional manner. The rotation of the shaft147of the turbo140in turn causes the blades internal to a compressor142to rotate. The rotation of the blades of the compressor142compresses the air130in the first air intake section134to a higher pressure in a second air intake section150, providing for the use of an increased amount of the fuel128on a stoichiometric basis.

The methanol/air mixture126enters the first combustion cylinder110A through the intake manifold122and first intake valve152A. The mixture of the fuel128introduced through the direct injector154A and the methanol/air mixture126is introduced through the first intake valve152A. The autoignition of the fuel128ignites the methanol/air mixture126in the first combustion cylinder110A to form the exhaust146, which exits the first combustion cylinder110A through a first exhaust valve156A. In a similar manner, the methanol/air mixture126enters the second combustion cylinder110B through the intake manifold122and second intake valve152B. The autoignition of the fuel128ignites the methanol/air mixture126in the second combustion cylinder110B to form the exhaust146, which exits the second combustion cylinder110B through a second exhaust valve156B. It should be noted that the direct injector154A and the direct injector154B may not be used if the internal combustion engine system100uses gasoline or other fuel types, as those ignition systems can use spark plugs and the like. The presently disclosed subject matter is not limited to any particular combustion configuration.

Methanol158is injected into the second air intake section150at a methanol injection port160in a heating section162of the second air intake section150. It should be noted that various examples of the presently disclosed subject matter can include more than one methanol injection port160. The heating section162is the portion of the second air intake section150that is internally disposed within a tubular, hollow exhaust heater164, physically and functionally described in more detail inFIGS.2-4, below. In the internal combustion engine system100, the exhaust146can exit the internal combustion engine system100thru exhaust port166A and/or166B using throttle valve168. As the throttle valve168is opened, an increasing portion of the exhaust146exiting the turbine144into exhaust exit section170exits the exhaust port166B, while some of the exhaust146exits the exhaust port166A. If the throttle valve168is closed, the exhaust146exiting the turbine144into the exhaust exit section170exits the exhaust port166A. The throttle valve168may be opened and closed for various reasons. For example, a thermocouple169may be affixed to the exhaust exit section170. The thermocouple169may be used to detect a temperature in the exhaust exit section170. In another example, a thermocouple177is affixed to the intake manifold122to detect the temperature of the intake manifold122. It should be noted that more or fewer thermocouples may be used, as well as thermocouples in other locations. A temperature controller173receives a signal171from the thermocouple169and/or the signal178from the thermocouple177and determines if the signal171or the signal178represents a temperature above a setpoint. If the temperature is above a setpoint, the temperature controller outputs a signal175to open the throttle valve168, reducing the amount of heating of fluids entering the intake manifold122, reducing the temperature of the exhaust exit section170and/or the intake manifold122. In some examples, the signal175is a proportional signal, meaning that the signal is not an open fully or close fully signal, but rather, a signal that instructs the throttle valve to open more or close more. This proportional signal can be used by the temperature controller173using a map, whereby at certain temperatures of the first combustion cylinder110A, the throttle valve168is to be set to a specific opening value. Therefore, instead of, or in addition to, the use of the setpoints, the temperature controller173can use proportional signals to control the temperature of the first combustion cylinder110A. The temperature controller173may be used to control temperatures of other components, the use of which is considered to be within the scope of the presently disclosed subject matter.

As noted above, the methanol158has a relatively high latent heat of vaporization of methanol, including when compared to the fuel128. Thus, the portions of the methanol158, when injected into the second air intake section150through the methanol injection port160, can remain liquid. In some examples, most, if not all, of the methanol158injected through the methanol injection port160is vapor by the time the methanol158reaches the intake manifold122, or at least the first intake valve152A and/or the second intake valve152B. The heating section162is used to increase the temperature of the air130and the methanol158moving through the heating section162. The exhaust146moves through the hollow exhaust heater164and around an exterior wall172of the heating section162. As the exhaust146moving through the hollow exhaust heater164is at a relatively higher temperature than the air130moving the heating section162, a portion of the heat from the exhaust146is transferred into the heating section162through a heat transfer process. At least a portion of the heat transferred into the heating section162is transferred into the air130moving thru the heating section162.

Moving through the heating section162, the methanol158can be heated in various physical processes such as radiation, convention, and conduction. A first process can be a heat exchange between the methanol158and the air130. As noted above, heat transfer from thermal energy transferred through the exterior wall172of the heating section162heats the air130that is traveling through the heating section162. The heated air130in turn heats the methanol158. In another example, the methanol158itself is heated by the thermal energy transferred through the exterior wall172of the heating section162from heat transfer. In a still further example, the methanol158can impact or impinge upon an inner surface180of the heating section162. The inner surface180receives heat from the exterior wall172. Upon the methanol158impinging upon the inner surface180of the heating section162, heat is transferred into the methanol158at the location of contact. In a still further example, methanol158that is in liquid form may be heated by higher temperature methanol158, including methanol158in vapor form. These and other forms of heating the methanol158into a vapor form may be used and are considered to be within the scope of the presently disclosed subject matter.

The input of heat (thermal energy) into the liquid methanol158from the air130and/or the inner surface180of the heating section162in the various heating forms described above can increase the amount of the methanol158that is in vapor form as opposed to the methanol in liquid form prior to entering into the first combustion cylinder110A and/or the second combustion cylinder110B. As noted above, this heating process occurs in the heating section162, an example of which is described in more detail inFIG.2, below.

FIG.2is a cross-sectional view of the heating section162of system100ofFIG.1, along with other components that input or receive fluid from the heating section162. Some parts of the internal combustion engine102have been omitted fromFIG.2for ease of illustration and not by way of limitation. Shown inFIG.2is the exhaust manifold124that receives the exhaust146from the internal combustion engine102(shown inFIG.1, above). The exhaust146enters the turbine144and is exhausted through the exhaust exit section170. The throttle valve168, controlled by the signal175from the temperature controller173, controls the volumetric flowrate of the exhaust146that enters the hollow exhaust heater164and exits through the exhaust port166A as opposed to the exhaust port166B. The rotational motion provided by the turbine144causes the compressor142of the turbo140to compress the air130into compressed air tube143prior to entering the heating section162. The compressed air tube143is fitted through the hollow exhaust heater164at hermetically sealed junction145and into the heating section162. The hermetically sealed junction145allows the air130in the compressed air tube143to travel through the hollow exhaust heater164and into the heating section162without the air130and the exhaust146mixing. The following description in which a heating section is internal to a hollow exhaust heater uses a hermetically sealed junction to allow air to move into the heating section without mixing with the exhaust, providing for a “tube within a tube” configuration. The compressed air130exits the heating section162into the second air intake section150and into the intake manifold122, shown inFIG.1.

The hollow exhaust heater164is a generally tubular shape having a heater outer wall200and a heater inner wall202extending axially along center axis AB. The heating section162is a generally tubular shape having the exterior wall172and the inner surface180extending axially along center axis AB. An outer heat exchange cavity205is defined between the heater inner wall202and the exterior wall172. An interior heat exchange cavity206is defined as the hollow within the inner surface180. In the outer heat exchange cavity205, heat from the exhaust146entering at exhaust input port212transfers heat from the exhaust146to the exterior wall172primarily through convective heating as the exhaust146moves from the exhaust input port212to the exhaust port166A. The thermal energy of the exhaust146transfers from the exterior wall172through to the inner surface180along the heating section162.

In the interior heat exchange cavity206, the methanol158in liquid form introduced through the methanol injection port160is illustrated as droplets220. It is understood that some methanol158may enter the interior heat exchange cavity206already in vapor form. The presently disclosed subject matter is not limited to liquid methanol158injection. Once injected, the interior heat exchange cavity206has a methanol/air mixture221. As mentioned above, there are several example forms of heat exchange in the interior heat exchange cavity206to vaporize the methanol158droplets220. An example of heat exchange is convention/conduction when a droplet220impinges upon the inner surface180, which is heated from the exhaust146moving past and around the exterior wall172. An example impingement location222of the inner surface180is illustrated inFIG.2. The impingement location222is a location of the inner surface180to which at least a portion of the droplets220travel as the droplets are introduced through the methanol injection port160. Upon contact with the impingement location222, the droplets220receive heat from the inner surface180, whereby at least a portion of the droplets receive enough heat to vaporize into a gaseous form of methanol158. It should be noted that the entire inner surface180is a potential impingement location222. The illustration of a singular impingement location222is merely for purposes of explanation. Further, in some examples, the impingement location222is the same surface as the inner surface180and is merely one or more locations of the inner surface180.

Another example form of heat exchange sufficient to vaporize the methanol158droplets220is radiant heat/convention from the inner surface180. In some examples, the droplets220do not contact or impinge upon the inner surface180. However, heat from the inner surface180can be radiant heat that inputs heat to the droplets. Further, the heat from the inner surface180can also transfer to the droplets using convective cooling. Thus, as the methanol158moves along the center axis AB from A to B, thermal energy from the inner surface180is added to the droplets220along the travel path of the droplets220. A still further example form of heat exchange may be convective heating between the air130and the methanol158if the methanol158is at a lower temperature than the air130in the interior heat exchange cavity206. In some examples, the compressor142adds heat to the air130when compressing the air130.

The more heat and time available to vaporize the methanol158droplets220, the probability of the droplets220being vaporized increases. Thus, the manner in which heat is introduced into an interior heat exchange cavity and the manner in which fluid flows may be modified. When looking at the flows inFIG.2, the exhaust146and the air130traveling through the exhaust heater164travel along the central axis AB from location A to location B in a concurrent flow.FIGS.3-9illustrate other configurations for heat transfer.

FIG.3is a cross-sectional view of an exhaust heater300showing a counterflow design, in accordance with various examples of the presently disclosed subject matter. In a counterflow design, fluids traveling in opposing directions exchange thermal energy with each other. The exhaust heater300includes an exhaust tube302and an air supply tube304. The exhaust tube302is tubular in shape, extending longitudinally along central axis CD and is defined by an outer surface303and an inner surface308. An exhaust tube interior void306is defined by the inner surface308of the exhaust tube302and an outer surface310of the air supply tube304. The air supply tube304is disposed within the exhaust tube302along length L longitudinally along a central axis CD. Exhaust312, such as exhaust received from a turbine (not shown) or simply the exhaust received from an engine without a turbo, enters the exhaust tube302through exhaust input314and travels generally longitudinally along the central axis CD around the air supply tube304in the direction from D to C and exits through exhaust exit316. Air318enters the air supply tube304through air input320and travels generally longitudinally along the central axis CD in the air supply tube304in the direction from C to D and exits through air exit322. Thus, the directions of the air318and the exhaust312are counter to each other (i.e. different directions).

Along with extracting heat as desired from the exhaust312, heat can also be maintained or added to the system to assist with heating methanol358injected into the air supply tube304. The technologies for adding or maintaining heat within an air supply tube can be used individually or as series of steps in a protocol. Examples of these technologies are illustrated inFIG.4, below.

FIG.4is a cross-sectional view of an exhaust heater400illustrating heat retention and addition technologies, in accordance with various examples of the presently disclosed subject matter. It should be noted that although the exhaust heater400is shown in a counterflow configuration, the technologies described herein are applicable to various types of flow designs, including, concurrent flow whereby fluids exchanging thermal energy travel in the same direction and crossflow whereby fluids exchanging thermal energy travel normal or perpendicular to each other. InFIG.4, the exhaust heater400includes an exhaust tube402and an air supply tube404. An exhaust tube interior void406is defined by an inner surface408of the exhaust tube402and an outer surface410of the air supply tube404. The air supply tube404is disposed within the exhaust tube402in a manner similar to the exhaust heater300ofFIG.3. Exhaust412, such as exhaust from a turbine (not shown) or simply the exhaust from an engine without a turbo, enters the exhaust tube402through exhaust input414and travels generally longitudinally along the central axis VT around the air supply tube404in the direction from location T to location V and exits through exhaust exit416. Air418enters the air supply tube404through air input420and travels generally longitudinally along the central axis VT in the air supply tube404in the direction from V to T and exits through air exit422.

As noted above, there may be various technologies for maintaining heat or adding heat into the air supply tube404. In one example, an insulation424may be disposed on at least a portion of the outer surface410of the air supply tube404. The insulation424includes, but is not limited to, mineral glass fiber, mineral wool, rock wool, glass wool, and polyurethane. The presently disclosed subject matter is not limited to any particular type of the insulation424. In some examples, the insulation424is used to maintain heat within the air supply tube404by reducing the rate of heat transfer from the air supply tube404to an exterior of the air supply tube404, thus increasing the amount of heat added to methanol458injected into the air supply tube404. Another type of insulation424, which may be in addition to or in place of other types, is a double walled construction of the air supply tube404. In a double walled construction, the air supply tube404has two walls, sometimes separated by an insulative material such as air, foam, or an insulative construction such as the use of a partial vacuum. The presently disclosed subject matter is not limited to any particular double (or more)—walled technology.

In some examples, heat may be added to the air supply tube404using a heater426. The heater426is disposed on the outer surface410of the air supply tube404and is powered by a heater power supply428. The heater power supply428can be an electrical power supply, whereby current flowing into the heater426increases the temperature of the heater426, thus adding heat to the outer surface410and eventually into the air supply tube404. It should be noted that other forms of heating may be used and are considered to be within the currently disclosed subject matter. Returning toFIG.4, the heater426can be used to supplement or replace heat provided by the exhaust412. For example, during a startup of a combustion engine, the temperature and/or flow of the exhaust412may not be enough to appreciably add enough heat to the outer surface410. Until the exhaust412temperature is high enough or has been flowing long enough, the outer surface410may be of a temperature insufficient to add enough heat into the air supply tube404to vaporize the methanol458. In this example, the heater426is used to provide heat until the exhaust412is sufficient to add heat.

It should be noted that the heater426can be used in various configurations. For example, although illustrated as affixed to the outer surface410, the heater426can also be used in other locations, such as in the air supply tube404and the like. Further, the heater426size and number may vary. The presently disclosed subject matter is not limited to any particular configuration. As noted above, the various forms of either maintaining heat or adding heat to vaporize methanol can be used in various situations such as a startup procedure, illustrated in more detail inFIG.5.

FIG.5illustrates a process500for starting up a work machine that uses methanol as a component of a fuel supply, in accordance with one or more examples of the present disclosure. The process500and other processes described herein are illustrated as example flow graphs, each operation of which may represent a sequence of operations. The order in which the operations are described is not intended to be construed as a limitation, and any number of the described operations can be combined in any order and/or in parallel to implement the processes.

The process500includes operation502where the internal combustion engine102is started. During an example startup, such as an example startup in which the internal combustion engine102has not operated for an appreciable amount of time, the internal combustion engine102and its components may be at or near the temperature of the environment (“room temperature”). In this regard, the internal combustion engine102can use one or more forms of insulation, such as the insulation424, which may be various forms of insulation or double walled construction of the air supply tube404. This insulation424can help to maintain heat, including in the air supply tube404, to vaporize at least a portion of the methanol458.

At operation504, the temperature controller173determines whether or not the heater426is needed or desired to increase the temperature of the air supply tube404. During some operations, enough heat from the exhaust412is sufficient to increase the temperature of the air supply tube404to vaporize a desired percentage of liquid methanol. However, in one example, at operation504, the temperature controller173determines that the air supply tube404temperature is not increasing at a desired or required rate to a specified setpoint temperature. For example, the temperature controller173can receive data that a percentage of liquid methanol injected has remained liquid. Therefore, the heater426can be an option at operation504.

If the temperature controller173determines that the heater426is not needed (504-No), at operation506, the temperature controller173maintains the current configuration, whereby the internal combustion engine102continues the startup process. If the heater is needed, at operation508, the temperature controller173transmits a signal that activates the heater426or causes the heater426to turn on. As described above, the heater426can add heat to the air supply tube404until the heat from the exhaust is sufficient to take over for the heater426. The use of the heater426can help vaporize the methanol while the air supply tube404is being heated from a lower temperature by the exhaust.

At operation510, the temperature controller173determines if a temperature or time setpoint is reached. For example, the heater426can be programed to operate for a certain period of time. In another example, the heater426can be programmed to operate until a temperature recorded by the thermocouple169meets a setpoint. At operation512, in response to a setpoint being reached, the heater426is turned off and the operation506is commenced, whereby the configuration of the internal combustion engine102is maintained. At operation510, in response to the temperature controller173determining that a setpoint has not been reached, at operation508, the heater426is maintained on.

The heater426can be used to provide heat during a phase of operation of the internal combustion engine102in which heat from the exhaust is insufficient to vaporize methanol to a desired degree. However, the heater426can be used in steady state and startup (or shutdown) conditions. The heater426can be used to provide supplementary heat during an idling condition of the internal combustion engine102, whereby the exhaust is minimal and may not have enough heat to vaporize the methanol to a desired degree. However, other structural technologies may be used to increase the amount of heat added to methanol or the probability that methanol will be heated, explained in more detail inFIGS.6and7, below.

FIG.6is a cross-sectional view of an exhaust heater600that uses structural components to increase heat addition to methanol, in accordance with one or more examples of the present disclosure. InFIG.6, the exhaust heater600includes an exhaust tube602and an air supply tube604. The air supply tube604is in an annular space606defined by an interior surface608of the exhaust tube602, a “tube in tube” configuration” as explained inFIG.2, above. Exhaust610from an internal combustion engine, such as the internal combustion engine102ofFIG.1, enters the exhaust tube602at exhaust input612and exits at exhaust output614. Air616enters the air supply tube604from air input618, through air input tube620and exits through air output622. From air output622, the air616continues to an engine. It should be noted that the air616and/or the exhaust610may be from compressed sources (such as a compressor and turbine, respectively) or from uncompressed sources. The presently disclosed subject matter is not limited to any particular source.

Heat from the exhaust610travels through the exhaust tube602and into an annular space624of the air supply tube604, the annular space624defined by an internal surface626of the air supply tube604. To increase the potential for introducing heat from the exhaust610to methanol658injected into the annular space624through injection port628, the air supply tube604includes a fin630. The fin630is a piece of metallic or semi-metallic piece affixed or attached to, or installed onto, the internal surface626and is positioned so that droplets632of the methanol658have a probability of impacting an injector facing surface634of the fin630. The fin630is affixed to the internal surface626in a way that the fin630conducts heat from the internal surface626, which is heated by the exhaust610, to the injector facing surface634of the fin630. Surfaces of the fin630, such as the injector facing surface634and a fin surface636is heated by heated air616moving over the fin630and by heat transfer into the air supply tube604by the exhaust610moving over the air supply tube604.

Using the fin630as a heated target location for the droplets632can increase the probability of some of the droplets632being vaporized. In some examples, heat conduction from a solid surface, such as the injector facing surface634of the fin630has a greater rate of heating than heat conducted between two fluids, such as the air616and the methanol658, moving in a space. The reason for that is that for two fluids to exchange heat in an appreciable manner, molecules of the two fluids need to be in proximity to each other. In the context when one of the fluids is a gas (the air616), the molecules are relatively far apart, reducing the probability of a molecule of air616being in proximity to the droplets632. In a different manner, the fin630is a solid surface position at a location in which the droplets632are likely to strike. Thus, not only does the density of molecules (solid versus gas) of the fin630increase the probability of heat transfer, the position of the fin630in relation to the droplets632also increases the probability of heat transfer. The placement, size, location, and number of fins630can be different in different configurations. For example, inFIG.6, a single fin630is illustrated, though more fins may be used. Further, the fin630has a “wing shape” to reduce aerodynamic resistance of the fin630to the flow of the air616. The fin630includes a leading edge640and a trailing edge642that can be shaped to reduce the aerodynamic resistance of the fin630. Further, the fin630is placed and sized in a manner that also increases heat transfer, while potentially reducing drag, illustrated in more detail inFIG.7, below.

FIG.7is a cross-sectional view of the exhaust heater600taken along cut plane XY and viewed from central axis WZ from location Z to location W, as illustrated inFIG.6, in accordance with one or more examples of the present disclosure. Shown inFIG.7are the exhaust tube602and the air supply tube604. Further illustrated are the fin630, the fin surface636and the injector facing surface634of the fin630. As discussed inFIG.6, the fin630is placed in a directional path GT of the methanol droplets632so that the droplets632are directed to the injector facing surface634of the fin630. Also illustrated is connecting interface702, which connects the fin630to the internal surface626of the air supply tube604. The connecting interface702can be a weld or some other form of attachment technology used to affix the fin630to the internal surface626of the air supply tube604. In some examples, the connecting interface702is a heat transfer interface that provides for the conduction of heat from the internal surface626or the air supply tube604to the fin630.

As mentioned previously, the presently disclosed subject matter is not limited to any particular type of engine configuration. Various examples of the presently disclosed subject matter can be used in various types of engines with various types of technological implementations. For example, the presently disclosed subject matter can be used with engines having intercoolers (FIG.8) and exhaust gas recirculation (EGR) technology (FIG.9).

FIG.8is a fluid flow diagram illustrating a system800for heating methanol in a system that uses an intercooler, in accordance with one or more examples of the present disclosure. The system ofFIG.8includes an exhaust tube802and an air supply tube804. Exhaust806from an engine808enters a turbine810. The exhaust806, at a relatively higher pressure and temperature than air812causes the turbine810to rotate the blades of a compressor814. The rotational motion of blades of the compressor814causes the air to be compressed upon entry into the air supply tube804to provide a source of compressed air to the engine808for combustion (fuel injectors not shown). In the system800ofFIG.8, an intercooler/charged-air-cooled (CAC)816is used. The intercooler/CAC cools compressed air before it enters a combustion chamber (not shown) of the engine808. A purpose is to lower the temperature of the air812entering the engine808to, in some examples, improve emissions and output power efficiency. Excessive temperatures can lead to reduced charge density and higher combustion temperatures which can affect torque, power, and emissions. Thus, in the system800ofFIG.8, the intercooler/CAC816is used as a control mechanism to moderate and control the heat of the air812entering the engine808.

Compressed air818exiting the compressor814can travel into the air supply tube804and/or into an intercooler tube832. In a first example, the compressed air818enters the air supply tube804, where turbine exhaust820enters the exhaust tube802and adds heat to the compressed air818moving through the air supply tube804in a manner described above inFIGS.1-6. Methanol822is injected into the air supply tube804, whereby the heat added by the turbine exhaust820increases the heat of the methanol822, thereby vaporizing at least a portion of the methanol822. If it is desired to moderate a temperature of the compressed air818entering the engine808, a powertrain control module824sends a signal825to close, at least partially, compressed air valve826and a signal828to open, at least partially, intercooler valve830. When the intercooler valve830is at least partially opened, a portion of the compressed air818enters the intercooler tube832and into the intercooler/CAC816. Thus, the powertrain control module824opens and closes, or throttles if not fully opened or closed, the compressed air valve826and the intercooler valve830to maintain a desired temperature of the compressed air818into the engine808.

In a similar manner, the powertrain control module824uses two exhaust valves, exhaust heater valve834and exhaust bypass valve836, to control the amount of heating applied to the compressed air818. To reduce the amount of heating by the turbine exhaust820, the powertrain control module824sends a signal838to at least partially close the exhaust heater valve834and a signal840to at least partially open the exhaust bypass valve836, thereby reducing the amount of the turbine exhaust820that heats the air supply tube804. To increase the amount of heating by the turbine exhaust820, the powertrain control module824sends the signal838to at least partially open the exhaust heater valve834and the signal840to at least partially closer the exhaust bypass valve836, thereby increasing the amount of the turbine exhaust820that heats the air supply tube804. The turbine exhaust820that flows through the exhaust bypass valve836enters intercooler/CAC bypass tube842and, like the turbine exhaust820that flows through the exhaust tube802, enters an aftertreatment system844. The aftertreatment system844can be a release into ambient air812or emission-reduction technologies like a catalytic converter.

Often components of exhaust, like nitrogen oxides (NOx) can be a significant source of pollution and greenhouse gases. Nitrogen oxides are normally formed in the process of combustion in the engine cylinders. However, their formation increases dramatically at higher combustion temperatures (above 1600° C. or 2912° F.). A technology designed to ameliorate the production of NOx is exhaust gas recirculation (EGR). The EGR system reduces the combustion temperature by diverting a small portion of the exhaust gases back into the intake manifold. Because exhaust gases are primarily no longer combustible, EGR systems introduce exhaust gas into the air intake to dilute the intake air with exhaust gases. Because exhaust gases are no longer combustible, the diluted air/fuel mixture is less combustible.FIG.9is an example of the use of an EGR system.

FIG.9is a fluid flow diagram illustrating a system900for heating methanol in a system that uses exhaust gas recirculation to moderate NOx production, in accordance with one or more examples of the present disclosure. The system900includes a turbine902and a compressor904. The turbine902receives exhaust906from an engine908. The pressure of the exhaust906turns the turbine902, which in turn turns the compressor904to compress air910into compressed air913. The exhaust906leaving the turbine902exhausts into an aftertreatment system915to allow the exhaust906to enter the air910. To heat methanol909to at least partially vaporize a portion of the methanol909, the methanol909is injected into the exhaust906through methanol injector(s)911. It should be noted that the process of injecting the methanol909into the exhaust906to at least partially vaporize the methanol909can also be used in conjunction with the methanol heating technologies described inFIGS.1-8, above, whereby the methanol is injected into a compressed air stream that is heated by the exhaust. For example, a powertrain control module912sends a signal914to at least partially open exhaust heater valve916to allow a portion of the exhaust906to enter an exhaust heater918that heats the compressed air913. The methanol909can be injected into an air supply tube920in a manner similar toFIGS.1-8, above.

The system900includes an exhaust gas recirculation (EGR) cooler922. The EGR cooler922is a heat exchanger that cools the exhaust906by using engine coolant924. Cooled exhaust926enters a mixer929that mixes the cooled exhaust926with the compressed air913. The mixture of the cooled exhaust926and the compressed air913can travel two paths, the paths of which may not be entirely exclusive (meaning not one or the other, but both at the same time). The first path is that the mixture of the cooled exhaust926and the compressed air913enters the air supply tube920and then the engine908. The second path is that the mixture of the cooled exhaust926and the compressed air913enters an intercooler/charged-air-cooled (CAC)928is used. The intercooler/CAC928cools compressed air913before it enters a combustion chamber (not shown) of the engine908. To allow for at least a portion of the mixture of the cooled exhaust926and the compressed air913to enter the air supply tube920, the powertrain control module912sends signal930to at least partially open an air supply valve932. To allow for at least a portion of the mixture931of the cooled exhaust926and the compressed air913to enter the intercooler/CAC928, the powertrain control module912sends signal934to at least partially open intercooler valve936.

FIG.10depicts a component level view of the powertrain control module824for use with the systems and methods described herein. The powertrain control module824can comprise several components to execute the above-mentioned functions, including the powertrain control module912ofFIG.9. As discussed below, the powertrain control module824can comprise memory1002including an operating system (OS)1004and one or more standard applications1006. The standard applications1006can include many features common to engines such as ignition timing, engine control management, and the like. The standard applications1006can also include valve signal generators to control various valves, including the compressed air valve826and the intercooler valve830, among others.

The powertrain control module824can also comprise one or more processors1010having one or more cores and one or more of removable storage1012, non-removable storage1014, transceiver(s)1016, output device(s)1018, and input device(s)1020. In various implementations, the memory1002can be volatile (such as random access memory (RAM)), non-volatile (such as read only memory (ROM), flash memory, etc.), or some combination of the two. The OS1004contains the modules and software that support basic functions of the powertrain control module824, including the generation of signals to open and close valves.

In some implementations, the processor(s)1010can be one or more central processing units (CPUs), graphics processing units (GPUs), both CPU and GPU, or any other processing unit. The powertrain control module824may also include additional data storage devices (removable and/or non-removable) such as, for example, magnetic disks, optical disks, or tape. Such additional storage is illustrated inFIG.10by removable storage1012and non-removable storage1014.

Non-transitory computer-readable media may include volatile and nonvolatile, removable and non-removable tangible, physical media implemented in technology for storage of information, such as computer readable instructions, data structures, program modules, or other data. The memory1002, removable storage1012, and non-removable storage1014are all examples of non-transitory computer-readable media. Non-transitory computer-readable media include, but are not limited to, RAM, ROM, electronically erasable programmable ROM (EEPROM), flash memory or other memory technology, compact disc ROM (CD-ROM), digital versatile discs (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other tangible, physical medium which can be used to store the desired information and which can be accessed by the powertrain control module824. Any such non-transitory computer-readable media may be part of the powertrain control module824or may be a separate database, databank, remote server, or cloud-based server. In some implementations, the transceiver(s)1016include any transceivers known in the art. In some examples, the transceiver(s)1016are used to transmit signals to open or close valves in various examples disclosed herein.

The transceiver(s)1016may also include one or more radio transceivers that perform the function of transmitting and receiving radio frequency communications via an antenna (e.g., Wi-Fi or Bluetooth®).

In some implementations, the output device(s)1018include any output devices known in the art, such as a display (e.g., a liquid crystal or thin-film transistor (TFT) display), a touchscreen, speakers, a vibrating mechanism, or a tactile feedback mechanism. Thus, the output device(s) can include a screen or display. In various implementations, input device(s)1020include any input devices known in the art. For example, the input device(s)1020may include a camera, a microphone, or a keyboard/keypad.

INDUSTRIAL APPLICABILITY

The present disclosure describes systems and processes for the heating of methanol158, and to at least partially vaporize the methanol158prior to entering a combustion cylinder110A or110B of an internal combustion engine102. Methanol can be used in a variety of types of combustion engines, and the availability of methanol can be greater than other sources of alternate fuel additives because methanol can be produced in a variety of ways using a variety of stock material ranging from natural gas to coal. Vaporizing the methanol reduces the thermal load on the engine (i.e. the amount of heat needed to vaporize the methanol in order to combust the methanol). Methanol is injected into an air supply tube404with compressed air. Exhaust intake148is ported around the air supply tube404, heating the walls of the air supply tube404, which in turn heats and vaporizes at least a portion of the liquid methanol.

Vaporizing methanol has several benefits. In some examples, because of its relatively high heat of vaporization, liquid methanol can remove heat from internal components of an engine. This can change the thermal characteristics of the engine, potentially causing reduced performance because methanol, like other hydrocarbons, need to be in vapor form to combust. If entering a combustion chamber in liquid form, the liquid methanol will remove thermal energy from a combustion process in order to vaporize, thus reducing the pressure in the combustion chamber, and in turn, reducing engine performance. Additionally, liquid methanol can cause random perturbations (or deviations) in the conditions of a combustion cylinder, increasing cycle-to-cycle variations and decreasing combustion stability. Reducing the amount of methanol entering into a combustion chamber in a liquid phase can improve combustion stability and reduce cycle-to-cycle variations. Further, liquid methanol can be corrosive, reducing the life-expectancy of an engine or causing mechanical issues.

In some examples, different types of flow patterns can be used to increase thermal energy transfer between the relatively warmer exhaust gases and the methanol. In some examples, a counterflow, whereby the exhaust and the air entrained with the liquid methanol travel in opposite directions, can be beneficial. The reason for this is that a greater temperature difference creates a greater thermal driving force. In a concurrent flow, the temperature of the fluids (the air318and the exhaust312) come closer, reducing the thermal driving force, thus, reducing the rate of heat exchange. In the countercurrent flow design ofFIG.3, there is a relatively greater temperature difference between the fluids (the air318and the exhaust312) as compared to a concurrent flow design, thus increasing the rate of heat exchange and extracting a higher proportion of heat content from the exhaust312to the air318

Unless explicitly excluded, the use of the singular to describe a component, structure, or operation does not exclude the use of plural such components, structures, or operations or their equivalents. As used herein, the word “or” refers to any possible permutation of a set of items. For example, the phrase “A, B, or C” refers to at least one of A, B, C, or any combination thereof, such as any of: A; B; C; A and B; A and C; B and C; A, B, and C; or multiple of any item such as A and A; B, B, and C; A, A, B, C, and C; etc.