Patent Description:
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. <CIT> ("the `<NUM> application") describes a system configured to raise the temperature of methanol stored in a storage tank. The system of the '<NUM> 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 `<NUM> 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 '<NUM> does not solve issues relating to the above-noted issues relating to the use of methanol as a fuel. Other systems and methods are known from <CIT>, <CIT> and <CIT>.

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

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.

Wherever possible, the same reference numbers will be used throughout the drawings to refer to same or like parts. Referring to <FIG>, there is shown an internal combustion engine system <NUM>, in accordance with an example of the present disclosure. In the example shown in <FIG>, the internal combustion engine system <NUM> includes an internal combustion engine <NUM> having an engine housing <NUM>. The internal combustion engine <NUM> further includes a first piston 106A and a second piston 106B. The first piston 106A is disposed within an interior volume 108A of a first combustion cylinder 110A. The interior volume 108A is defined by an inner surface 112A of the first combustion cylinder 110A. The second piston 106B is disposed within an interior volume 108B of a second combustion cylinder 110B. The interior volume 108B is defined by an inner surface 112B of the second combustion cylinder 110B. The first piston 106A is movable between a first top dead center position 114A and first bottom dead center position 116A. The second piston 106B is movable between a second top dead center position 114B and second bottom dead center position 116B. The first piston 106A and the second piston 106B move between the first top dead center position 114A and the first bottom dead center position 116A, and the second top dead center position 114B and the second bottom dead center position 116B, respectively, to rotate a crankshaft <NUM> in a generally conventional manner.

The internal combustion engine system <NUM> further includes an intake manifold <NUM> and an exhaust manifold <NUM>. The intake manifold <NUM> supplies a methanol/air mixture <NUM> comprising methanol <NUM> and air <NUM>. A compression ignition fuel <NUM>, such as diesel fuel, is injected into the interior volume 108A of the first combustion cylinder 110A using direct injector 154A and the interior volume 108B of the second combustion cylinder 110B using direct injector 154B. The compression of the methanol/air mixture <NUM> and the fuel <NUM> causes the fuel <NUM> to autoignite and subsequently the methanol/air mixture <NUM> to ignite, forcing the first piston 106A from the first top dead center position 114A to the first bottom dead center position 116A position and the second piston 106B from the second top dead center position 114B to the second bottom dead center position 116B. _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 system <NUM> is a gasoline engine, the fuel <NUM> comprises one or more octanes of gasoline. It should be noted that the fuel <NUM> may additionally include fuel additives and the like.

The air <NUM> is introduced into a first air intake section <NUM> of the internal combustion engine system <NUM> at air intake <NUM>. The air <NUM> is compressed by a turbo140. The turbo <NUM> includes a compressor <NUM> and a turbine <NUM>. The turbine <NUM> receives exhaust <NUM> from the exhaust manifold <NUM>, through exhaust intake <NUM>, and into the turbine <NUM>. The exhaust <NUM> includes bi-products of the combustion process taking place within the internal combustion engine system <NUM> (explained in more detail, below), and thus, is at a relative high pressure and temperature as compared to the air <NUM>. The pressure (and temperature) of the exhaust <NUM> impinges on the blades of the turbine <NUM>, thereby causing the blades, and a shaft <NUM> of the turbo <NUM> connected thereto, to rotate in a conventional manner. The rotation of the shaft <NUM> of the turbo <NUM> in turn causes the blades internal to a compressor <NUM> to rotate. The rotation of the blades of the compressor <NUM> compresses the air <NUM> in the first air intake section <NUM> to a higher pressure in a second air intake section <NUM>, providing for the use of an increased amount of the fuel <NUM> on a stoichiometric basis.

The methanol/air mixture <NUM> enters the first combustion cylinder 110A through the intake manifold <NUM> and first intake valve 152A. The mixture of the fuel <NUM> introduced through the direct injector 154A and the methanol/air mixture <NUM> is introduced through the first intake valve 152A. The autoignition of the fuel <NUM> ignites the methanol/air mixture <NUM> in the first combustion cylinder 110A to form the exhaust <NUM>, which exits the first combustion cylinder 110A through a first exhaust valve 156A. In a similar manner, the methanol/air mixture <NUM> enters the second combustion cylinder 110B through the intake manifold <NUM> and second intake valve 152B. The autoignition of the fuel <NUM> ignites the methanol/air mixture <NUM> in the second combustion cylinder 110B to form the exhaust <NUM>, which exits the second combustion cylinder 110B through a second exhaust valve 156B. It should be noted that the direct injector 154A and the direct injector 154B may not be used if the internal combustion engine system <NUM> uses 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.

Methanol <NUM> is injected into the second air intake section <NUM> at a methanol injection port <NUM> in a heating section <NUM> of the second air intake section <NUM>. It should be noted that various examples of the presently disclosed subject matter can include more than one methanol injection port <NUM>. The heating section <NUM> is the portion of the second air intake section <NUM> that is internally disposed within a tubular, hollow exhaust heater <NUM>, physically and functionally described in more detail in <FIG>, below. In the internal combustion engine system <NUM>, the exhaust <NUM> can exit the internal combustion engine system <NUM> thru exhaust port 166A and/or 166B using throttle valve <NUM>. As the throttle valve <NUM> is opened, an increasing portion of the exhaust <NUM> exiting the turbine <NUM> into exhaust exit section <NUM> exits the exhaust port 166B, while some of the exhaust <NUM> exits the exhaust port 166A. If the throttle valve <NUM> is closed, the exhaust <NUM> exiting the turbine <NUM> into the exhaust exit section <NUM> exits the exhaust port 166A. The throttle valve <NUM> may be opened and closed for various reasons. For example, a thermocouple <NUM> may be affixed to the exhaust exit section <NUM>. The thermocouple <NUM> may be used to detect a temperature in the exhaust exit section <NUM>. In another example, a thermocouple <NUM> is affixed to the intake manifold <NUM> to detect the temperature of the intake manifold <NUM>. It should be noted that more or fewer thermocouples may be used, as well as thermocouples in other locations. A temperature controller <NUM> receives a signal <NUM> from the thermocouple <NUM> and/or the signal <NUM> from the thermocouple <NUM> and determines if the signal <NUM> or the signal <NUM> represents a temperature above a setpoint. If the temperature is above a setpoint, the temperature controller outputs a signal <NUM> to open the throttle valve <NUM>, reducing the amount of heating of fluids entering the intake manifold <NUM>, reducing the temperature of the exhaust exit section <NUM> and/or the intake manifold <NUM>. In some examples, the signal <NUM> is 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 controller <NUM> using a map, whereby at certain temperatures of the first combustion cylinder 110A, the throttle valve <NUM> is to be set to a specific opening value. Therefore, instead of, or in addition to, the use of the setpoints, the temperature controller <NUM> can use proportional signals to control the temperature of the first combustion cylinder 110A. The temperature controller <NUM> may 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 methanol <NUM> has a relatively high latent heat of vaporization of methanol, including when compared to the fuel <NUM>. Thus, the portions of the methanol <NUM>, when injected into the second air intake section <NUM> through the methanol injection port <NUM>, can remain liquid. In some examples, most, if not all, of the methanol <NUM> injected through the methanol injection port <NUM> is vapor by the time the methanol <NUM> reaches the intake manifold <NUM>, or at least the first intake valve 152A and/or the second intake valve 152B. The heating section <NUM> is used to increase the temperature of the air <NUM> and the methanol <NUM> moving through the heating section <NUM>. The exhaust <NUM> moves through the hollow exhaust heater <NUM> and around an exterior wall <NUM> of the heating section <NUM>. As the exhaust <NUM> moving through the hollow exhaust heater <NUM> is at a relatively higher temperature than the air <NUM> moving the heating section <NUM>, a portion of the heat from the exhaust <NUM> is transferred into the heating section <NUM> through a heat transfer process. At least a portion of the heat transferred into the heating section <NUM> is transferred into the air <NUM> moving thru the heating section <NUM>.

Moving through the heating section <NUM>, the methanol <NUM> can be heated in various physical processes such as radiation, convention, and conduction. A first process can be a heat exchange between the methanol <NUM> and the air <NUM>. As noted above, heat transfer from thermal energy transferred through the exterior wall <NUM> of the heating section <NUM> heats the air <NUM> that is traveling through the heating section <NUM>. The heated air <NUM> in turn heats the methanol <NUM>. In another example, the methanol <NUM> itself is heated by the thermal energy transferred through the exterior wall <NUM> of the heating section <NUM> from heat transfer. In a still further example, the methanol <NUM> can impact or impinge upon an inner surface <NUM> of the heating section <NUM>. The inner surface <NUM> receives heat from the exterior wall <NUM>. Upon the methanol <NUM> impinging upon the inner surface <NUM> of the heating section <NUM>, heat is transferred into the methanol <NUM> at the location of contact. In a still further example, methanol <NUM> that is in liquid form may be heated by higher temperature methanol <NUM>, including methanol <NUM> in vapor form. These and other forms of heating the methanol <NUM> into 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 methanol <NUM> from the air <NUM> and/or the inner surface <NUM> of the heating section <NUM> in the various heating forms described above can increase the amount of the methanol <NUM> that is in vapor form as opposed to the methanol in liquid form prior to entering into the first combustion cylinder 110A and/or the second combustion cylinder 110B. As noted above, this heating process occurs in the heating section <NUM>, an example of which is described in more detail in <FIG>, below.

<FIG> is a cross-sectional view of the heating section <NUM> of system <NUM> of <FIG>, along with other components that input or receive fluid from the heating section <NUM>. Some parts of the internal combustion engine <NUM> have been omitted from <FIG> for ease of illustration and not by way of limitation. Shown in <FIG> is the exhaust manifold <NUM> that receives the exhaust <NUM> from the internal combustion engine <NUM> (shown in <FIG>, above). The exhaust <NUM> enters the turbine <NUM> and is exhausted through the exhaust exit section <NUM>. The throttle valve <NUM>, controlled by the signal <NUM> from the temperature controller <NUM>, controls the volumetric flowrate of the exhaust <NUM> that enters the hollow exhaust heater <NUM> and exits through the exhaust port 166A as opposed to the exhaust port 166B. The rotational motion provided by the turbine <NUM> causes the compressor <NUM> of the turbo <NUM> to compress the air <NUM> into compressed air tube <NUM> prior to entering the heating section <NUM>. The compressed air tube <NUM> is fitted through the hollow exhaust heater <NUM> at hermetically sealed junction <NUM> and into the heating section <NUM>. The hermetically sealed junction <NUM> allows the air <NUM> in the compressed air tube <NUM> to travel through the hollow exhaust heater <NUM> and into the heating section <NUM> without the air <NUM> and the exhaust <NUM> mixing. 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 air <NUM> exits the heating section <NUM> into the second air intake section <NUM> and into the intake manifold <NUM>, shown in <FIG>.

The hollow exhaust heater <NUM> is a generally tubular shape having a heater outer wall <NUM> and a heater inner wall <NUM> extending axially along center axis AB. The heating section <NUM> is a generally tubular shape having the exterior wall <NUM> and the inner surface <NUM> extending axially along center axis AB. An outer heat exchange cavity <NUM> is defined between the heater inner wall <NUM> and the exterior wall <NUM>. An interior heat exchange cavity <NUM> is defined as the hollow within the inner surface <NUM>. In the outer heat exchange cavity <NUM>, heat from the exhaust <NUM> entering at exhaust input port <NUM> transfers heat from the exhaust <NUM> to the exterior wall <NUM> primarily through convective heating as the exhaust <NUM> moves from the exhaust input port <NUM> to the exhaust port 166A. The thermal energy of the exhaust <NUM> transfers from the exterior wall <NUM> through to the inner surface <NUM> along the heating section <NUM>.

In the interior heat exchange cavity <NUM>, the methanol <NUM> in liquid form introduced through the methanol injection port <NUM> is illustrated as droplets <NUM>. It is understood that some methanol <NUM> may enter the interior heat exchange cavity <NUM> already in vapor form. The presently disclosed subject matter is not limited to liquid methanol <NUM> injection. Once injected, the interior heat exchange cavity <NUM> has a methanol/air mixture <NUM>. As mentioned above, there are several example forms of heat exchange in the interior heat exchange cavity <NUM> to vaporize the methanol <NUM> droplets <NUM>. An example of heat exchange is convention/conduction when a droplet <NUM> impinges upon the inner surface <NUM>, which is heated from the exhaust <NUM> moving past and around the exterior wall <NUM>. An example impingement location <NUM> of the inner surface <NUM> is illustrated in <FIG>. The impingement location <NUM> is a location of the inner surface <NUM> to which at least a portion of the droplets <NUM> travel as the droplets are introduced through the methanol injection port <NUM>. Upon contact with the impingement location <NUM>, the droplets <NUM> receive heat from the inner surface <NUM>, whereby at least a portion of the droplets receive enough heat to vaporize into a gaseous form of methanol <NUM>. It should be noted that the entire inner surface <NUM> is a potential impingement location <NUM>. The illustration of a singular impingement location <NUM> is merely for purposes of explanation. Further, in some examples, the impingement location <NUM> is the same surface as the inner surface <NUM> and is merely one or more locations of the inner surface <NUM>.

Another example form of heat exchange sufficient to vaporize the methanol <NUM> droplets <NUM> is radiant heat/convention from the inner surface <NUM>. In some examples, the droplets <NUM> do not contact or impinge upon the inner surface <NUM>. However, heat from the inner surface <NUM> can be radiant heat that inputs heat to the droplets. Further, the heat from the inner surface <NUM> can also transfer to the droplets using convective cooling. Thus, as the methanol <NUM> moves along the center axis AB from A to B, thermal energy from the inner surface <NUM> is added to the droplets <NUM> along the travel path of the droplets <NUM>. A still further example form of heat exchange may be convective heating between the air <NUM> and the methanol <NUM> if the methanol <NUM> is at a lower temperature than the air <NUM> in the interior heat exchange cavity <NUM>. In some examples, the compressor <NUM> adds heat to the air <NUM> when compressing the air <NUM>.

The more heat and time available to vaporize the methanol <NUM> droplets <NUM>, the probability of the droplets <NUM> being 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 in <FIG>, the exhaust <NUM> and the air <NUM> traveling through the exhaust heater <NUM> travel along the central axis AB from location A to location B in a concurrent flow. <FIG> illustrate other configurations for heat transfer.

<FIG> is a cross-sectional view of an exhaust heater <NUM> showing 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 heater <NUM> includes an exhaust tube <NUM> and an air supply tube <NUM>. The exhaust tube <NUM> is tubular in shape, extending longitudinally along central axis CD and is defined by an outer surface <NUM> and an inner surface <NUM>. An exhaust tube interior void <NUM> is defined by the inner surface <NUM> of the exhaust tube <NUM> and an outer surface <NUM> of the air supply tube <NUM>. The air supply tube <NUM> is disposed within the exhaust tube <NUM> along length L longitudinally along a central axis CD. Exhaust <NUM>, such as exhaust received from a turbine (not shown) or simply the exhaust received from an engine without a turbo, enters the exhaust tube <NUM> through exhaust input <NUM> and travels generally longitudinally along the central axis CD around the air supply tube <NUM> in the direction from D to C and exits through exhaust exit <NUM>. Air <NUM> enters the air supply tube <NUM> through air input <NUM> and travels generally longitudinally along the central axis CD in the air supply tube <NUM> in the direction from C to D and exits through air exit <NUM>. Thus, the directions of the air <NUM> and the exhaust <NUM> are counter to each other (i.e. different directions).

Along with extracting heat as desired from the exhaust <NUM>, heat can also be maintained or added to the system to assist with heating methanol <NUM> injected into the air supply tube <NUM>. 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 in <FIG>, below.

<FIG> is a cross-sectional view of an exhaust heater <NUM> illustrating heat retention and addition technologies, in accordance with various examples of the presently disclosed subject matter. It should be noted that although the exhaust heater <NUM> is 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. In <FIG>, the exhaust heater <NUM> includes an exhaust tube <NUM> and an air supply tube <NUM>. An exhaust tube interior void <NUM> is defined by an inner surface <NUM> of the exhaust tube <NUM> and an outer surface <NUM> of the air supply tube <NUM>. The air supply tube <NUM> is disposed within the exhaust tube <NUM> in a manner similar to the exhaust heater <NUM> of <FIG>. Exhaust <NUM>, such as exhaust from a turbine (not shown) or simply the exhaust from an engine without a turbo, enters the exhaust tube <NUM> through exhaust input <NUM> and travels generally longitudinally along the central axis VT around the air supply tube <NUM> in the direction from location T to location V and exits through exhaust exit <NUM>. Air <NUM> enters the air supply tube <NUM> through air input <NUM> and travels generally longitudinally along the central axis VT in the air supply tube <NUM> in the direction from V to T and exits through air exit <NUM>.

As noted above, there may be various technologies for maintaining heat or adding heat into the air supply tube <NUM>. In one example, an insulation <NUM> may be disposed on at least a portion of the outer surface <NUM> of the air supply tube <NUM>. The insulation <NUM> includes, 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 insulation <NUM>. In some examples, the insulation <NUM> is used to maintain heat within the air supply tube <NUM> by reducing the rate of heat transfer from the air supply tube <NUM> to an exterior of the air supply tube <NUM>, thus increasing the amount of heat added to methanol <NUM> injected into the air supply tube <NUM>. Another type of insulation <NUM>, which may be in addition to or in place of other types, is a double walled construction of the air supply tube <NUM>. In a double walled construction, the air supply tube <NUM> has 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 tube <NUM> using a heater <NUM>. The heater <NUM> is disposed on the outer surface <NUM> of the air supply tube <NUM> and is powered by a heater power supply <NUM>. The heater power supply <NUM> can be an electrical power supply, whereby current flowing into the heater <NUM> increases the temperature of the heater <NUM>, thus adding heat to the outer surface <NUM> and eventually into the air supply tube <NUM>. It should be noted that other forms of heating may be used and are considered to be within the currently disclosed subject matter. Returning to <FIG>, the heater <NUM> can be used to supplement or replace heat provided by the exhaust <NUM>. For example, during a startup of a combustion engine, the temperature and/or flow of the exhaust <NUM> may not be enough to appreciably add enough heat to the outer surface <NUM>. Until the exhaust <NUM> temperature is high enough or has been flowing long enough, the outer surface <NUM> may be of a temperature insufficient to add enough heat into the air supply tube <NUM> to vaporize the methanol <NUM>. In this example, the heater <NUM> is used to provide heat until the exhaust <NUM> is sufficient to add heat.

It should be noted that the heater <NUM> can be used in various configurations. For example, although illustrated as affixed to the outer surface <NUM>, the heater <NUM> can also be used in other locations, such as in the air supply tube <NUM> and the like. Further, the heater <NUM> size 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 in <FIG>.

<FIG> illustrates a process <NUM> for 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 process <NUM> and 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 process <NUM> includes operation <NUM> where the internal combustion engine <NUM> is started. During an example startup, such as an example startup in which the internal combustion engine <NUM> has not operated for an appreciable amount of time, the internal combustion engine <NUM> and its components may be at or near the temperature of the environment ("room temperature"). In this regard, the internal combustion engine <NUM> can use one or more forms of insulation, such as the insulation <NUM>, which may be various forms of insulation or double walled construction of the air supply tube <NUM>. This insulation <NUM> can help to maintain heat, including in the air supply tube <NUM>, to vaporize at least a portion of the methanol <NUM>.

At operation <NUM>, the temperature controller <NUM> determines whether or not the heater <NUM> is needed or desired to increase the temperature of the air supply tube <NUM>. During some operations, enough heat from the exhaust <NUM> is sufficient to increase the temperature of the air supply tube <NUM> to vaporize a desired percentage of liquid methanol. However, in one example, at operation <NUM>, the temperature controller <NUM> determines that the air supply tube <NUM> temperature is not increasing at a desired or required rate to a specified setpoint temperature. For example, the temperature controller <NUM> can receive data that a percentage of liquid methanol injected has remained liquid. Therefore, the heater <NUM> can be an option at operation <NUM>.

If the temperature controller <NUM> determines that the heater <NUM> is not needed (<NUM> - No), at operation <NUM>, the temperature controller <NUM> maintains the current configuration, whereby the internal combustion engine <NUM> continues the startup process. If the heater is needed, at operation <NUM>, the temperature controller <NUM> transmits a signal that activates the heater <NUM> or causes the heater <NUM> to turn on. As described above, the heater <NUM> can add heat to the air supply tube <NUM> until the heat from the exhaust is sufficient to take over for the heater <NUM>. The use of the heater <NUM> can help vaporize the methanol while the air supply tube <NUM> is being heated from a lower temperature by the exhaust.

At operation <NUM>, the temperature controller <NUM> determines if a temperature or time setpoint is reached. For example, the heater <NUM> can be programed to operate for a certain period of time. In another example, the heater <NUM> can be programmed to operate until a temperature recorded by the thermocouple <NUM> meets a setpoint. At operation <NUM>, in response to a setpoint being reached, the heater <NUM> is turned off and the operation <NUM> is commenced, whereby the configuration of the internal combustion engine <NUM> is maintained. At operation <NUM>, in response to the temperature controller <NUM> determining that a setpoint has not been reached, at operation <NUM>, the heater <NUM> is maintained on.

The heater <NUM> can be used to provide heat during a phase of operation of the internal combustion engine <NUM> in which heat from the exhaust is insufficient to vaporize methanol to a desired degree. However, the heater <NUM> can be used in steady state and startup (or shutdown) conditions. The heater <NUM> can be used to provide supplementary heat during an idling condition of the internal combustion engine <NUM>, 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 in <FIG> and <FIG>, below.

<FIG> is a cross-sectional view of an exhaust heater <NUM> that uses structural components to increase heat addition to methanol, in accordance with one or more examples of the present disclosure. In <FIG>, the exhaust heater <NUM> includes an exhaust tube <NUM> and an air supply tube <NUM>. The air supply tube <NUM> is in an annular space <NUM> defined by an interior surface <NUM> of the exhaust tube <NUM>, a "tube in tube" configuration" as explained in <FIG>, above. Exhaust <NUM> from an internal combustion engine, such as the internal combustion engine <NUM> of <FIG>, enters the exhaust tube <NUM> at exhaust input <NUM> and exits at exhaust output <NUM>. Air <NUM> enters the air supply tube <NUM> from air input <NUM>, through air input tube <NUM> and exits through air output <NUM>. From air output <NUM>, the air <NUM> continues to an engine. It should be noted that the air <NUM> and/or the exhaust <NUM> may 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 exhaust <NUM> travels through the exhaust tube <NUM> and into an annular space <NUM> of the air supply tube <NUM>, the annular space <NUM> defined by an internal surface <NUM> of the air supply tube <NUM>. To increase the potential for introducing heat from the exhaust <NUM> to methanol <NUM> injected into the annular space <NUM> through injection port <NUM>, the air supply tube <NUM> includes a fin <NUM>. The fin <NUM> is a piece of metallic or semi-metallic piece affixed or attached to, or installed onto, the internal surface <NUM> and is positioned so that droplets <NUM> of the methanol <NUM> have a probability of impacting an injector facing surface <NUM> of the fin <NUM>. The fin <NUM> is affixed to the internal surface <NUM> in a way that the fin <NUM> conducts heat from the internal surface <NUM>, which is heated by the exhaust <NUM>, to the injector facing surface <NUM> of the fin <NUM>. Surfaces of the fin <NUM>, such as the injector facing surface <NUM> and a fin surface <NUM> is heated by heated air <NUM> moving over the fin <NUM> and by heat transfer into the air supply tube <NUM> by the exhaust <NUM> moving over the air supply tube <NUM>.

Using the fin <NUM> as a heated target location for the droplets <NUM> can increase the probability of some of the droplets <NUM> being vaporized. In some examples, heat conduction from a solid surface, such as the injector facing surface <NUM> of the fin <NUM> has a greater rate of heating than heat conducted between two fluids, such as the air <NUM> and the methanol <NUM>, 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 air <NUM>), the molecules are relatively far apart, reducing the probability of a molecule of air <NUM> being in proximity to the droplets <NUM>. In a different manner, the fin <NUM> is a solid surface position at a location in which the droplets <NUM> are likely to strike. Thus, not only does the density of molecules (solid versus gas) of the fin <NUM> increase the probability of heat transfer, the position of the fin <NUM> in relation to the droplets <NUM> also increases the probability of heat transfer. The placement, size, location, and number of fins <NUM> can be different in different configurations. For example, in <FIG>, a single fin <NUM> is illustrated, though more fins may be used. Further, the fin <NUM> has a "wing shape" to reduce aerodynamic resistance of the fin <NUM> to the flow of the air <NUM>. The fin <NUM> includes a leading edge <NUM> and a trailing edge <NUM> that can be shaped to reduce the aerodynamic resistance of the fin <NUM>. Further, the fin <NUM> is placed and sized in a manner that also increases heat transfer, while potentially reducing drag, illustrated in more detail in <FIG>, below.

<FIG> is a cross-sectional view of the exhaust heater <NUM> taken along cut plane XY and viewed from central axis WZ from location Z to location W, as illustrated in <FIG>, in accordance with one or more examples of the present disclosure. Shown in <FIG> are the exhaust tube <NUM> and the air supply tube <NUM>. Further illustrated are the fin <NUM>, the fin surface <NUM> and the injector facing surface <NUM> of the fin <NUM>. As discussed in <FIG>, the fin <NUM> is placed in a directional path GT of the methanol droplets <NUM> so that the droplets <NUM> are directed to the injector facing surface <NUM> of the fin <NUM>. Also illustrated is connecting interface <NUM>, which connects the fin <NUM> to the internal surface <NUM> of the air supply tube <NUM>. The connecting interface <NUM> can be a weld or some other form of attachment technology used to affix the fin <NUM> to the internal surface <NUM> of the air supply tube <NUM>. In some examples, the connecting interface <NUM> is a heat transfer interface that provides for the conduction of heat from the internal surface <NUM> or the air supply tube <NUM> to the fin <NUM>.

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>) and exhaust gas recirculation (EGR) technology (<FIG>).

<FIG> is a fluid flow diagram illustrating a system <NUM> for heating methanol in a system that uses an intercooler, in accordance with one or more examples of the present disclosure. The system of <FIG> includes an exhaust tube <NUM> and an air supply tube <NUM>. Exhaust <NUM> from an engine <NUM> enters a turbine <NUM>. The exhaust <NUM>, at a relatively higher pressure and temperature than air <NUM> causes the turbine <NUM> to rotate the blades of a compressor <NUM>. The rotational motion of blades of the compressor <NUM> causes the air to be compressed upon entry into the air supply tube <NUM> to provide a source of compressed air to the engine <NUM> for combustion (fuel injectors not shown). In the system <NUM> of <FIG>, an intercooler/charged-air-cooled (CAC) <NUM> is used. The intercooler/CAC cools compressed air before it enters a combustion chamber (not shown) of the engine <NUM>. A purpose is to lower the temperature of the air <NUM> entering the engine <NUM> to, 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 system <NUM> of <FIG>, the intercooler/CAC <NUM> is used as a control mechanism to moderate and control the heat of the air <NUM> entering the engine <NUM>.

Compressed air <NUM> exiting the compressor <NUM> can travel into the air supply tube <NUM> and/or into an intercooler tube <NUM>. In a first example, the compressed air <NUM> enters the air supply tube <NUM>, where turbine exhaust <NUM> enters the exhaust tube <NUM> and adds heat to the compressed air <NUM> moving through the air supply tube <NUM> in a manner described above in <FIG>. Methanol <NUM> is injected into the air supply tube <NUM>, whereby the heat added by the turbine exhaust <NUM> increases the heat of the methanol <NUM>, thereby vaporizing at least a portion of the methanol <NUM>. If it is desired to moderate a temperature of the compressed air <NUM> entering the engine <NUM>, a powertrain control module <NUM> sends a signal <NUM> to close, at least partially, compressed air valve <NUM> and a signal <NUM> to open, at least partially, intercooler valve <NUM>. When the intercooler valve <NUM> is at least partially opened, a portion of the compressed air <NUM> enters the intercooler tube <NUM> and into the intercooler/CAC <NUM>. Thus, the powertrain control module <NUM> opens and closes, or throttles if not fully opened or closed, the compressed air valve <NUM> and the intercooler valve <NUM> to maintain a desired temperature of the compressed air <NUM> into the engine <NUM>.

In a similar manner, the powertrain control module <NUM> uses two exhaust valves, exhaust heater valve <NUM> and exhaust bypass valve <NUM>, to control the amount of heating applied to the compressed air <NUM>. To reduce the amount of heating by the turbine exhaust <NUM>, the powertrain control module <NUM> sends a signal <NUM> to at least partially close the exhaust heater valve <NUM> and a signal <NUM> to at least partially open the exhaust bypass valve <NUM>, thereby reducing the amount of the turbine exhaust <NUM> that heats the air supply tube <NUM>. To increase the amount of heating by the turbine exhaust <NUM>, the powertrain control module <NUM> sends the signal <NUM> to at least partially open the exhaust heater valve <NUM> and the signal <NUM> to at least partially closer the exhaust bypass valve <NUM>, thereby increasing the amount of the turbine exhaust <NUM> that heats the air supply tube <NUM>. The turbine exhaust <NUM> that flows through the exhaust bypass valve <NUM> enters intercooler/CAC bypass tube <NUM> and, like the turbine exhaust <NUM> that flows through the exhaust tube <NUM>, enters an aftertreatment system <NUM>. The aftertreatment system <NUM> can be a release into ambient air <NUM> or 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 <NUM> or <NUM> °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> is an example of the use of an EGR system.

<FIG> is a fluid flow diagram illustrating a system <NUM> for 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 system <NUM> includes a turbine <NUM> and a compressor <NUM>. The turbine <NUM> receives exhaust <NUM> from an engine <NUM>. The pressure of the exhaust <NUM> turns the turbine <NUM>, which in turn turns the compressor <NUM> to compress air <NUM> into compressed air <NUM>. The exhaust <NUM> leaving the turbine <NUM> exhausts into an aftertreatment system <NUM> to allow the exhaust <NUM> to enter the air <NUM>. To heat methanol <NUM> to at least partially vaporize a portion of the methanol <NUM>, the methanol <NUM> is injected into the exhaust <NUM> through methanol injector(s) <NUM>. It should be noted that the process of injecting the methanol <NUM> into the exhaust <NUM> to at least partially vaporize the methanol <NUM> can also be used in conjunction with the methanol heating technologies described in <FIG>, above, whereby the methanol is injected into a compressed air stream that is heated by the exhaust. For example, a powertrain control module <NUM> sends a signal <NUM> to at least partially open exhaust heater valve <NUM> to allow a portion of the exhaust <NUM> to enter an exhaust heater <NUM> that heats the compressed air <NUM>. The methanol <NUM> can be injected into an air supply tube <NUM> in a manner similar to <FIG>, above.

The system <NUM> includes an exhaust gas recirculation (EGR) cooler <NUM>. The EGR cooler <NUM> is a heat exchanger that cools the exhaust <NUM> by using engine coolant <NUM>. Cooled exhaust <NUM> enters a mixer <NUM> that mixes the cooled exhaust <NUM> with the compressed air <NUM>. The mixture of the cooled exhaust <NUM> and the compressed air <NUM> can 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 exhaust <NUM> and the compressed air <NUM> enters the air supply tube <NUM> and then the engine <NUM>. The second path is that the mixture of the cooled exhaust <NUM> and the compressed air <NUM> enters an intercooler/charged-air-cooled (CAC) <NUM> is used. The intercooler/CAC <NUM> cools compressed air <NUM> before it enters a combustion chamber (not shown) of the engine <NUM>. To allow for at least a portion of the mixture of the cooled exhaust <NUM> and the compressed air <NUM> to enter the air supply tube <NUM>, the powertrain control module <NUM> sends signal <NUM> to at least partially open an air supply valve <NUM>. To allow for at least a portion of the mixture <NUM> of the cooled exhaust <NUM> and the compressed air <NUM> to enter the intercooler/CAC <NUM>, the powertrain control module <NUM> sends signal <NUM> to at least partially open intercooler valve <NUM>.

<FIG> depicts a component level view of the powertrain control module <NUM> for use with the systems and methods described herein. The powertrain control module <NUM> can comprise several components to execute the above-mentioned functions, including the powertrain control module <NUM> of <FIG>. As discussed below, the powertrain control module <NUM> can comprise memory <NUM> including an operating system (OS) <NUM> and one or more standard applications <NUM>. The standard applications <NUM> can include many features common to engines such as ignition timing, engine control management, and the like. The standard applications <NUM> can also include valve signal generators to control various valves, including the compressed air valve <NUM> and the intercooler valve <NUM>, among others.

The powertrain control module <NUM> can also comprise one or more processors <NUM> having one or more cores and one or more of removable storage <NUM>, non-removable storage <NUM>, transceiver(s) <NUM>, output device(s) <NUM>, and input device(s) <NUM>. In various implementations, the memory <NUM> can 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 OS <NUM> contains the modules and software that support basic functions of the powertrain control module <NUM>, including the generation of signals to open and close valves.

In some implementations, the processor(s) <NUM> can be one or more central processing units (CPUs), graphics processing units (GPUs), both CPU and GPU, or any other processing unit. The powertrain control module <NUM> may 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 in <FIG> by removable storage <NUM> and non-removable storage <NUM>.

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 memory <NUM>, removable storage <NUM>, and non-removable storage <NUM> are 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 module <NUM>. Any such non-transitory computer-readable media may be part of the powertrain control module <NUM> or may be a separate database, databank, remote server, or cloud-based server. In some implementations, the transceiver(s) <NUM> include any transceivers known in the art. In some examples, the transceiver(s) <NUM> are used to transmit signals to open or close valves in various examples disclosed herein.

The transceiver(s) <NUM> may 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) <NUM> include 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) <NUM> include any input devices known in the art. For example, the input device(s) <NUM> may include a camera, a microphone, or a keyboard/keypad.

The present disclosure describes systems and processes for the heating of methanol <NUM>, and to at least partially vaporize the methanol <NUM> prior to entering a combustion cylinder 110A or 110B of an internal combustion engine <NUM>. 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 tube <NUM> with compressed air. Exhaust intake <NUM> is ported around the air supply tube <NUM>, heating the walls of the air supply tube <NUM>, 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 air <NUM> and the exhaust <NUM>) come closer, reducing the thermal driving force, thus, reducing the rate of heat exchange. In the countercurrent flow design of <FIG>, there is a relatively greater temperature difference between the fluids (the air <NUM> and the exhaust <NUM>) as compared to a concurrent flow design, thus increasing the rate of heat exchange and extracting a higher proportion of heat content from the exhaust <NUM> to the air <NUM>.

Claim 1:
An exhaust heater (<NUM>) system, comprising:
an exhaust tube (<NUM>) having an exhaust tube (<NUM>) outer surface, an exhaust tube (<NUM>) inner surface (<NUM>), and a longitudinal central axis extending substantially centrally through the exhaust tube (<NUM>), the exhaust tube (<NUM>) inner surface (<NUM>) defining an interior space (<NUM>) of the exhaust tube (<NUM>);
an air supply tube (<NUM>) disposed within the interior space (<NUM>) of the exhaust tube (<NUM>), the air supply tube (<NUM>) having an air supply tube outer surface (<NUM>) and an air supply tube inner surface (<NUM>);
a methanol injector (<NUM>) configured to inject methanol (<NUM>) into the air supply tube (<NUM>);
a turbine (<NUM>) configured to receive exhaust (<NUM>) from an engine and direct the exhaust (<NUM>) to the exhaust tube (<NUM>); and
a compressor (<NUM>) powered by turbine (<NUM>), the compressor (<NUM>) configured to direct compressed air (<NUM>) into the air supply tube (<NUM>), wherein heat from the exhaust (<NUM>) in the exhaust tube (<NUM>) heats and vaporizes at least a portion of the methanol (<NUM>) injected into the air supply tube (<NUM>).