System and method for fuel switching at a cylinder

Abstract

This document describes an internal combustion engine system (100). The system described herein allows switching from methanol to diesel as the first fuel at the cylinder level rather than at the system level (212). A valve at the inlet of the first return tank (112) is used to isolate the first return tank (112) of the first fuel (212). The first fuel pump (120) is de-energized, thereby allowing the inlet valve to open. The ignition fuel (210) is then directed to both the first fuel inlet line (124) and the ignition fuel inlet line (116) and into the injector (102).

Description

Technical Field

[0001] This disclosure generally relates to operating a prime mover, and more specifically to switching from one type of fuel as a first fuel to another type of fuel as a first fuel. Background Technology

[0002] Prime movers for working machines, such as internal combustion engines, fuel cells, and batteries, are widely used across various industries. Internal combustion engines, for example, can operate using a variety of different liquid fuels, gaseous fuels, and various blends. Spark-ignition engines use an electric spark to ignite the combustion of fuel and air, while compression-ignition engines typically compress the gas in the cylinder to the auto-ignition threshold, allowing fuel ignition to begin without a spark. Furthermore, in ignition-ignition applications, including dual-fuel applications, a mixture of gaseous fuels (such as natural gas and air) is delivered to the cylinder, and ignition is triggered by a relatively small direct injection of a compressed ignition fuel (e.g., an ignition fuel), which automatically ignites to trigger the ignition of a relatively large main charge.

[0003] As part of efforts to improve the efficiency of these engines, researchers have explored various types of alternative fuel blends, including alcohol fuels such as methanol and ethanol, and a variety of other fuels. In some examples, methanol is injected directly into the engine cylinders and ignited with an ignition fuel or spark. Using methanol offers several advantages compared to other alternative fuels. For example, methanol has a relatively low production cost, and its production cost may be even lower compared to other alternative fuels. Furthermore, methanol's availability is greater than other alternative fuel sources because it can be produced in various ways using materials ranging from natural gas to coal. As mentioned above, an ignition fuel may be needed to assist in the ignition of the methanol. Diesel fuel is often used as an ignition fuel to ignite the low-hexadecyl methanol fuel used in methanol-powered engines. Typically, diesel fuel, as an ignition fuel, is injected into the combustion chamber before the methanol fuel is injected. The ignition of the diesel (or ignition fuel) causes the methanol fuel to ignite.

[0004] In some cases, it may be necessary to use both diesel and methanol in an engine. Efforts have been made to provide methanol and / or diesel in varying amounts based on engine status (i.e., start-up) or power level. For example, Chinese patent application CN201621424210U (“'210 application”) by Hu YongJun describes a system configured to switch between two different types of fuel. The system of the '210 application uses a “dual-fuel-rail multi-way valve” to allow the user to switch the fuel consumed by the engine from one type of fuel to another. The valve is described as a shell and spool piston valve, whereby in one position, one type of fuel is supplied to the engine, and in another position, another type of fuel is supplied to the engine. However, the system described in the '210 application has some drawbacks. For example, although the valve allows the user to switch from one type of fuel to another, the switching takes time as the fuel being switched flows through the system and into the combustion chamber. If the fuel system has a relatively large volume, there may be a significant time lag between the valve position switching and the eventual introduction of the desired fuel into the combustion chamber.

[0005] The examples disclosed herein relate to overcoming the shortcomings of such systems. Summary of the Invention

[0006] In one aspect of the currently disclosed subject matter, a system includes: an internal combustion engine for burning a first fuel and an ignition fuel, wherein the engine includes injectors in cylinders of the engine, the injectors being configured to inject the ignition fuel and the first fuel for combustion; a first fuel pump fluidly connected to a first fuel supply to supply the first fuel to the injectors via a first fuel inlet line and fluidly disconnectable from the first fuel supply; an ignition fuel pump fluidly connected to an ignition fuel supply to supply the ignition fuel to the injectors via an ignition fuel inlet line; and a first return isolation valve for... The first position fluidly disconnects the first excess fuel line from the first return tank and fluidly connects the first excess fuel line to the first return isolation valve in the second position; the first outlet valve is configured to fluidly connect the first fuel to the first fuel inlet line when the first outlet valve is in the first position and fluidly disconnect the first fuel from the first fuel inlet line when the first outlet valve is in the second position; and the input bypass line is configured to supply a portion of the ignition fuel from the ignition fuel pump to the first fuel inlet line when the first outlet valve is in the second position.

[0007] In another aspect of the currently disclosed subject matter, an injector system includes: an injector comprising: an ignition fuel inlet for receiving ignition fuel from an ignition fuel pump fluidly connected to an ignition fuel supply via an ignition fuel input line; an ignition fuel outlet for removing excess ignition fuel into an ignition return tank; a first fuel inlet for receiving fuel via a first fuel input line; and a first fuel outlet for removing excess fuel received in the first fuel input line via a first excess fuel line, wherein the fuel comprises: first fuel from the first fuel pump when a first outlet valve fluidly connecting the first fuel pump to the first fuel input line is open and when an input valve for providing a portion of the ignition fuel from the ignition fuel pump to an input bypass line in the first fuel input line is closed; or ignition fuel from the ignition fuel pump when the first outlet valve is closed and when the input valve is open.

[0008] In another aspect of the currently disclosed subject matter, a method for switching between methanol and diesel as a first fuel at a cylinder includes: supplying first fuel from a first fuel pump to a first fuel input line through the first fuel input valve when the first fuel input valve is in a first position; supplying ignition fuel from an ignition fuel pump to the ignition fuel input line; de-energizing the first fuel pump to stop the flow of the first fuel into the first fuel input line; positioning the first fuel input valve in a second position to direct the flow of the first fuel to a first fuel tank; and positioning a bypass valve in the second position to direct a portion of the ignition fuel from the ignition fuel pump into an input bypass line, and then into the first fuel input line. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of a fuel injector system using "cylinder position" fuel switching according to one or more examples of this disclosure.

[0010] Figure 2 This is a schematic diagram of an injector system based on various examples of the currently disclosed subject matter, showing the flow of ignition fuel from the ignition fuel supply and first fuel from the first fuel supply configured for fuel switching at the cylinder.

[0011] Figure 3 This is a schematic diagram of a system configured for fuel switching at a cylinder, based on various examples of currently disclosed topics, showing multiple cylinders.

[0012] Figure 4 This is a schematic diagram of a system configured according to various examples of the currently disclosed subject matter for use in a cylinder switching of an engine using an offset valve to switch more than one cylinder from one fuel to another.

[0013] Figure 5 It is a schematic diagram of a system configured for fuel switching and fuel purging at the cylinder, based on various examples of currently disclosed topics.

[0014] Figure 6 Methods for operating systems, based on various examples of currently disclosed topics, are shown, in which fuel switching at the cylinder can be performed.

[0015] Figure 7 This is a schematic diagram of an injector system based on various examples of the currently disclosed subject matter, showing the flow of ignition fuel from the ignition fuel supply and first fuel from the first fuel supply configured for fuel switching at the cylinder. Detailed Implementation

[0016] Wherever possible, the same reference numerals will be used throughout the accompanying drawings to denote the same or similar parts. Refer to the accompanying drawings. Figure 1 This is a schematic diagram of a fuel injector system 100 using "injector location" fuel switching according to one or more examples of this disclosure. As used herein, "cylinder location" means that fuel entering a cylinder of a combustion engine is switched from one fuel delivery system (e.g., methanol in a methanol fuel rail) to another fuel delivery system (e.g., diesel or ignition fuel rail), while a "system location" configuration switches fuel being delivered to the rail from one fuel to another. For example, in a dual-fuel combustion engine system that uses a methanol fuel rail to deliver methanol to the cylinder, a "system location" configuration switches the fuel that needs to be supplied to the methanol fuel rail from methanol to another fuel, such as diesel. The cylinder still receives fuel from the methanol fuel rail, but receives a different fuel, such as diesel, pumped into the methanol fuel rail. In the "cylinder location" configuration, the switching from one fuel to another occurs at the cylinder by switching the rail that delivers fuel to the cylinder from one fuel rail (such as a methanol fuel rail) to another fuel rail (such as a diesel or ignition fuel rail). It should be noted that the subject matter of the present disclosure does not require the use of fuel rails. Furthermore, the currently disclosed subject matter does not require all cylinders to be configured to switch configurations at the cylinder level. System 100 is an example of a cylinder-level configuration.

[0017] System 100 includes injector 102. Injector 102 is used to deliver one or more types of fuel into the combustion cylinder of a combustion engine (not shown). An example of injector 102 is given below. Figure 2 This is shown and described in more detail below. Return Figure 1The injector receives ignition fuel from ignition fuel supply 104 and first fuel from first fuel supply 106. In some examples, the ignition fuel is injected before or together with the first fuel. Figure 1 In the example, compression from a piston (not shown) is used to ignite an ignition fuel that is ignited due to its relatively high cetane number compared to other fuels. The relatively high temperatures generated during the ignition and combustion of the ignition fuel then provide sufficient pressure and temperature to burn a first fuel, which may not be easily ignited by compression. The ignition fuel may include a liquid fuel with a higher cetane / lower octane ratio, and the first fuel may include a liquid fuel with a lower cetane / higher octane ratio. In this context, the terms "higher" and "lower" can be understood as relative terms relative to each other. Thus, the ignition fuel may have a higher cetane number and a lower octane number compared to the first fuel. The ignition fuel may include any one or another of the following fuel types: diesel distillate fuels, dimethyl ether, biodiesel, hydrotreated vegetable oil (HVO), gas-to-liquid (GTL) renewable diesel, and various liquid fuels with cetane enhancers. The first fuel may include alcohol fuels, such as methanol or ethanol, naphtha, or other fuel types. Figure 1 For the purpose of this study, the ignition fuel is described as diesel fuel, and the first fuel is described as methanol, but as mentioned above, the subject matter currently disclosed can be used with other fuel types.

[0018] In an operating configuration where injector 102 receives ignition fuel via ignition fuel supply 104, ignition fuel pump 114 is in fluid communication with ignition fuel supply 104. Ignition fuel pump 114 pumps ignition fuel through ignition fuel inlet line 116 and into injector 102 for combustion. Excess ignition fuel exits injector 102 through ignition excess line 118 and enters ignition return tank 108. In the same configuration, injector 102 receives first fuel (e.g., methanol) from first fuel supply 106. First fuel pump 120 is in fluid communication with first fuel supply 106 and pumps the first fuel through a first outlet valve 122 in a first position (e.g., open), through first fuel inlet line 124, and into injector 102 for combustion. Excess first fuel exits injector 102 through first fuel excess line 126, through biased check valve 128, and enters first return tank 112. The biased check valve 128 is a first return isolation valve that fluidly disconnects the first return tank 112 from the system 100 in a first position and connects the first return tank 112 to the system 100 in a second position. In conjunction with the first outlet valve 122, the biased check valve 128 fluidly disconnects the first fuel supply 106 and the first fuel in the first return tank 112 from the system 100, thereby providing access to the ignition fuel in the first fuel inlet line 124, as described in more detail below.

[0019] During this configuration, when the first fuel is being used for combustion, as the first fuel pump 120 pumps and supplies the first fuel into the first fuel inlet line 124, the bias line 130 from the first fuel inlet line 124 provides a bias pressure (outlet pressure) to the bias check valve 128 to keep the bias check valve 128 open. It should be noted that the bias check valve 128 is one example of fluid shut-off technology because other technologies can be used. For example, instead of using the bias check valve 128, an actuated valve could be used, for example, an actuated valve that opens when the first fuel pump 120 is energized and closes when the first fuel pump 120 is de-energized. Figure 1 System 100 also includes two bypass lines for providing fluid flow paths to facilitate fuel switching at the cylinder. It should be understood that the use of bypass valves, solenoid-activated (electromagnetic) valves, etc., is merely for the purpose of illustrating the subject matter disclosed herein and is not intended to limit the scope of the subject matter. During the above-described configuration of pumping the first fuel into the injector 102, the input valve 132 of the input bypass line 134 is kept closed by the pressure of the first fuel pump 120 and the first fuel input line 124. Furthermore, in the same configuration, the outlet bypass valve 136 of the outlet bypass line 138 is kept closed by the pressure of the ignition excess line 118.

[0020] To switch from supplying first fuel to injector 102 for combustion to supplying ignition fuel to injector 102 for combustion, the first fuel pump 120 is de-energized. When the first fuel pump 120 is de-energized, the pressure in the bias line 130 from the first fuel input line 124 decreases, allowing the bias check valve 128 to close, thereby fluidly disconnecting the first return tank 112 from system 100. The decrease in pressure in the bias line 130 from the first fuel input line 124 further allows the input valve 132 of the input bypass line 134 to open and allows the first outlet valve 122 to close, thus fluidly connecting the ignition fuel input line 116 to the first fuel input line 124 and fluidly disconnecting the first fuel supply 106 from the first fuel input line 124. Furthermore, pressure from the first fuel excess line 126 opens the outlet bypass valve 136 of the outlet bypass line 138. Therefore, in this configuration, first fuel is no longer received from the first fuel supply 106. Furthermore, ignition fuel is pumped into the ignition fuel inlet line 116 and into the injector 102 for combustion, and also pumped through the inlet valve 132 of the inlet bypass line 134, through the first fuel inlet line 124, and into the injector 102 for combustion. Excess ignition fuel is directed to the ignition return tank 108 through both the excess ignition line 118 and the outlet bypass valve 136 of the outlet bypass line 138, thereby fluidly disconnecting the first return tank 112 by closing the bias check valve 128.

[0021] To switch back from supplying ignition fuel to injector 102 for combustion to supplying first fuel to injector 102 for combustion, the first fuel pump 120 is re-energized. When the first fuel pump 120 is re-energized, the pressure in the bias line 130 from the first fuel input line 124 increases, allowing the bias check valve 128 to open, thereby fluidly connecting the first return tank 112 to system 100. The increased pressure in the bias line 130 from the first fuel input line 124 further closes the input valve 132 of the input bypass line 134 and the first outlet valve 122, thus fluidly disconnecting the ignition fuel input line 116 from the first fuel input line 124 and fluidly connecting the first fuel supply 106 to the first fuel input line 124. Furthermore, the outlet bypass valve 136 of the outlet bypass line 138 closes, thus returning the system to the configuration of supplying first fuel to injector 102 for combustion. Figure 2 This will be shown in more detail elsewhere.

[0022] Figure 2 This is a schematic diagram of an injector system 200, based on various examples of the currently disclosed subject matter, illustrating a configuration for fuel switching at the cylinder. Figure 1The system 100 contains the flow of ignition fuel from ignition fuel supply 104 and first fuel from first fuel supply 106. Figure 2 In the above text, the same component reference numerals are used. Figure 1 The components described herein. It should be noted that, as... Figure 2 The injector 102 shown is merely to illustrate fluid flow in a fuel switching configuration at the cylinder, because the injector 102 and other components shown herein may have additional features, parts, or structures not shown in this or other figures but which may be used otherwise. Figure 2 The injector 102 injects fuel load 202 into cylinder 206 of engine 208 for combustion through injector port 204. It should be noted that although a single-port fuel injector 102 is shown, the subject matter disclosed herein can be used with other types of injectors, including injectors having separate ports for ignition fuel and first fuel, and is considered to be within the scope of the subject matter disclosed herein.

[0023] Fuel load 202 includes an ignition fuel 210 portion and a first fuel 212 portion. As described above, ignition fuel 210 is first injected to initiate the combustion process in cylinder 206. Injector 102 includes an ignition fuel inlet 214 and an ignition fuel outlet 216, the ignition fuel inlet being used to receive ignition fuel 210 from ignition fuel input line 116, and the ignition fuel outlet being used to remove excess ignition fuel 210 to ignition return box 108 via ignition excess line 118. Injector 102 also includes a first fuel inlet 218 and a first fuel outlet 220, the first fuel inlet being used to receive fuel, such as first fuel 212 or ignition fuel 210, from first fuel input line 124, and the first fuel outlet being used to remove excess first fuel 212 to first fuel excess line 126, biased check valve 128 and to first return box 112. To generate fuel load 202, injector 102 includes piston 222. Piston 222 is configured to create a vacuum in a first action to draw ignition fuel 210 and first fuel 212 into the injection chamber 224 of injector 102. Then, in a second action, piston 222 generates pressure to push the ignition fuel 210 and first fuel 212 from the injection chamber 224 into cylinder 206. Figure 2 In the example injector 102 shown, the ignition fuel 210 is injected first because the ignition fuel 210 is located at a lower position in the chamber relative to the first fuel 212 (i.e., fluidly closer to the injector orifice 204).

[0024] To switch from supplying first fuel 212 to injector 102 to using ignition fuel 210 for combustion, the first fuel pump 120 is de-energized. When the first fuel pump 120 is de-energized, the pressure in the bias line 130 from the first fuel input line 124 decreases, allowing the bias check valve 128 to close, thereby fluidly disconnecting the first return tank 112. The decrease in pressure in the bias line 130 from the first fuel input line 124 further allows the input valve 132 of the input bypass line 134 to open and allows the first outlet valve 122 to close, thus fluidly connecting the ignition fuel input line 116 to the first fuel input line 124 and fluidly disconnecting the first fuel supply 106 from the first fuel input line 124.

[0025] Pressure from the first excess fuel line 126 opens the outlet bypass valve 136 of the outlet bypass line 138. Therefore, in this configuration, first fuel 212 is no longer received from the first fuel supply 106. Furthermore, ignition fuel 210 is pumped into the ignition fuel input line 116 and into the injector 102 for combustion, and also pumped through the input valve 132 of the input bypass line 134, through the first fuel input line 124, and into the injector 102 for combustion. The excess ignition fuel 210 is directed to the ignition return tank 108 via both the excess ignition line 118 and the outlet bypass valve 136 of the outlet bypass line 138, thereby fluidly disconnecting the first return tank 112 by closing the bias check valve 128.

[0026] To switch back to a configuration where first fuel 212 is supplied to injector 102 for combustion and ignition fuel 210 is supplied to injector 102 as ignition fuel, the first fuel pump 120 is re-energized. When the first fuel pump 120 is re-energized, the pressure in the bias line 130 from the first fuel input line 124 increases, causing the bias check valve 128 to open, thereby fluidly connecting the first return tank 112 to system 100. The increased pressure in the bias line 130 from the first fuel input line 124 further closes the input valve 132 of the input bypass line 134 and the first outlet valve 122, thus fluidly disconnecting the ignition fuel input line 116 from the first fuel input line 124 and fluidly connecting the first fuel supply 106 to the first fuel input line 124. Furthermore, the outlet bypass valve 136 of the outlet bypass line 138 is closed, thereby returning the system to a configuration that supplies first fuel 212 to the injector 102 for combustion. In some configurations, the fuel rail can be used to supply ignition fuel 210 and / or first fuel 212 to more than one cylinder, such as... Figure 3 As shown in the image.

[0027] Figure 3This is a schematic diagram of a system 300 configured for fuel switching at cylinders, based on various examples of currently disclosed subjects, showing multiple cylinders. It should be noted that... Figure 3 Use the same component label for Figure 1 and 2 Components with similar configurations as described in [the document]. The use of "A" or "B" attached to the component label is intended to specify [the intended meaning]. Figure 1 and 2 The document describes more than one element with a similar configuration. Figure 3 System 300 includes Figure 1 The system 100 is an element in which an ignition fuel rail 304 and a first fuel rail 306 are added. As used herein, a "rail" is a fuel line that supplies fuel to one or more injectors, such as injectors 102A and 102B. It should be noted that injectors 102A and 102B may be a single injector capable of receiving both ignition fuel 210 and first fuel 212, or multiple injectors each capable of receiving either ignition fuel 210 or first fuel 212, such as... Figure 2 The single-port injector shown is capable of injecting both ignition fuel 210 and first fuel 212 through a single injection port, a multi-port injector that injects ignition fuel through one port and first fuel 212 through the other port, and / or combinations thereof.

[0028] Ignition fuel pump 114 pumps ignition fuel 210 into ignition fuel rail 304. First fuel pump 120 pumps first fuel 212 into first fuel rail 306. Excess first fuel 212 enters excess first fuel rail 310 and reaches first return tank 112. To switch from a configuration supplying first fuel 212 to injectors 102A and 102B to using ignition fuel 210 for combustion, first fuel pump 120 is de-energized. When first fuel pump 120 is de-energized, the pressure in bias lines 130A and 130B from first fuel inlet lines 124A and 124 decreases, respectively. The decrease in pressure allows bias check valves 128A and 128B to close, thereby fluidly disconnecting first return tank 112 from fuel inlet lines 124A and 124. The decrease in pressure in the bias lines 130A and 130B from the first fuel input lines 124A and 124 further allows the input valves 132A and 132B of the input bypass lines 134A and 134B to open, respectively. Furthermore, the first outlet valves 122A and 122B are closed, thus fluidly connecting the ignition input lines 116A and 116B to the first fuel input lines 124A and 124 and fluidly disconnecting the first fuel supply 106 from the first fuel input lines 124A and 124.

[0029] The pressure from the first excess fuel lines 126A and 126B opens the outlet bypass valves 136A and 136B of the outlet bypass lines 138A and 138B, respectively. Therefore, in this configuration, first fuel 212 is no longer received from the first fuel supply 106. Furthermore, ignition fuel 210 is pumped into ignition input lines 116A and 116B and into injectors 102A and 102B for combustion. Additionally, ignition fuel 210 is pumped through input valves 132A and 32B of input bypass lines 134A and 134B, through the first fuel input lines 124A and 124B, and into injectors 102A and 102B for combustion. Excess ignition fuel 210 is directed to the ignition return tank 108 via both the excess ignition lines 118A and 118B and the excess ignition fuel rail 308, as well as the outlet bypass valves 136A and 136B of the outlet bypass lines 138A and 138B. In this configuration, the first return tank 112 is fluidly disconnected by the closure of the biased check valves 128A and 128B, thus preventing ignition fuel from entering the first return tank 112.

[0030] To switch back to a configuration where first fuel 212 is supplied to injectors 102A and 102B for combustion and ignition fuel 210 is supplied to injectors 102A and 102B as ignition fuel, the first fuel pump 120 is re-energized. When the first fuel pump 120 is re-energized, pressure increases in the bias lines 130A and 130B from the first fuel input lines 124A and 124, respectively. This pressure increase causes bias check valves 128A and 128B to open, thereby fluidly connecting the first return tank 112 to the fuel input lines 124A and 124B. The increased pressure in the bias lines 130A and 130B from the first fuel input lines 124A and 124 further causes the input valves 132A and 132B of the input bypass lines 134A and 134B to close, respectively. Additionally, the first outlet valves 122A and 122B are opened, thus fluidly disconnecting the ignition inlet lines 116A and 116B from the first fuel inlet lines 124A and 124 and fluidly connecting the first fuel supply 106 to the first fuel inlet lines 124A and 124.

[0031] Pressure from the first excess fuel lines 126A and 126B causes the outlet bypass valves 136A and 136B of the outlet bypass lines 138A and 138B to close respectively. Therefore, in this configuration, first fuel 212 is received from the first fuel supply 106. Furthermore, ignition fuel 210 is pumped into ignition input lines 116A and 116B and into injectors 102A and 102B for combustion. The excess ignition fuel 210 is directed to the ignition return tank 108 via both the excess ignition lines 118A and 118B and the outlet bypass valves 136A and 136B of the outlet bypass lines 138A and 138B, thereby fluidly connecting the first return tank 112 through the opening of the biased check valves 128A and 128B. Because biased check valves 128A and 128B receive pressure input from the same source (first fuel pump 120), a single biased check valve is used in some examples (in...). Figure 4 (As shown in more detail below) It may be beneficial to use a combination of check valves instead of multiple check valves.

[0032] Figure 4 This is a schematic diagram of a system 400 for fuel switching at the cylinder level of an engine 409, configured according to various examples of currently disclosed subject matter, using a bias valve to switch more than one cylinder from one fuel to another. Figure 4 In this system 400, when the first fuel is supplied as the first combustion fuel to injectors 402A and 402B and the combustion of the first fuel is initiated using ignition fuel, the first fuel pump 420 is energized. When the first fuel pump 420 is energized, the pressure in the bias line 430 from the first fuel pump 420 causes the bias check valve 428 (first return isolation valve) to open, thereby fluidly connecting the first return tank 412 to the first fuel excess lines 426A and 426B. Therefore, a bias line (430) and a bias check valve (428) are used in system 400, instead of... Figure 1-4 The examples illustrate multiple bias lines or multiple bias check valves. In some examples, bias check valves with accompanying bias lines can be used for a single cylinder, multiple cylinders, or all cylinders of an engine. The subject matter disclosed herein is not limited to the number of cylinders.

[0033] In this configuration, the first fuel pump 420 pumps first fuel from the first fuel supply 406 to the first fuel rail 407. The first fuel travels from the first fuel rail 407 through first outlet valves 422A and 422B, first fuel inlet lines 424A and 424B, and into injectors 402A and 402B for combustion. Excess first fuel exits injectors 402A and 402B through first excess fuel lines 426A and 426, enters the excess first fuel rail 440, and then enters the first return tank 412. Furthermore, in this configuration, the ignition fuel pump 414 pumps ignition fuel from the ignition fuel supply 404 to the ignition fuel rail 405. The ignition fuel exits the ignition fuel rail 405 through ignition inlet lines 416A and 416B and enters injectors 402A and 402B for combustion. Excess ignition fuel leaves through excess ignition lines 418A and 418B, enters excess ignition fuel rail 442, and then enters ignition return box 408.

[0034] To switch from a configuration where a first fuel is supplied to injectors 402A and 402B as the first combustion fuel and ignition fuel is used to initiate combustion of the first fuel, the first fuel pump 420 is de-energized, thereby reducing the pressure at the outlet 421 of the first fuel pump 420. This pressure reduction is transmitted through the bias line 430, causing the bias check valve 428 to close, thereby fluidly disconnecting the first return tank 412 from the first fuel excess lines 426A and 426B. Therefore, in this configuration, ignition fuel is pumped by the ignition fuel pump 414 to the ignition fuel rail 405. The ignition fuel exits the ignition fuel rail 405 and enters the ignition input lines 416A and 416B of injectors 402A and 402B. The pressure of the ignition fuel relative to the first fuel opens the input valves 432A and 432B of the input bypass lines 434A and 434B and closes the first outlet valves 422A and 422B, thus fluidly connecting the ignition input lines 416A and 416B to the first fuel input lines 424A and 424B and fluidly disconnecting the first fuel supply 406 from the first fuel input lines 424A and 424B. Excess ignition fuel leaves through the excess ignition lines 418A and 418B, enters the excess ignition fuel rail 442, and enters the ignition return box 408. The outlet bypass valves 436A and 436B of the outlet bypass lines 438A and 438B remain closed by the pressure of the excess ignition lines 418A and 418B, respectively. The bias check valve 428 is closed to prevent excess ignition fuel from leaving through the first fuel excess lines 426A and 426B.

[0035] In various applications, for a variety of reasons, it may be necessary or desirable to remove at least a portion of the fuel (such as methanol) from parts of the engine. For example, the fuel may be corrosive, thus allowing it to remain in contact with various parts of the engine could weaken those parts. In another example, the fuel may be a safety hazard, potentially endangering the person using the engine if it remains within the engine or its fuel delivery system. Therefore, some engine systems include methods for purging a portion of the fuel from the system, examples of which are found in... Figure 5 Provided by China.

[0036] Figure 5 This is a schematic diagram of a system 500 configured for fuel switching and fuel purging at the cylinder, based on various examples of currently disclosed topics. Figure 5 In this process, when the first fuel is supplied to the injector 502 as the first combustion fuel and the combustion of the first fuel is initiated using ignition fuel, the first fuel pump 520 is energized. To fluidly connect the first return tank 512 to the first fuel supply 506, a first solenoid valve 528 is provided as a first return isolation valve. The first solenoid valve 528 is a normally closed solenoid valve opened by power 530. Power 530 can be derived from the power supplied to the first fuel pump 520. In this way, when the first fuel pump 520 is energized, the first solenoid valve 528 opens, and when the first fuel pump 520 is de-energized, the first solenoid valve 528 closes. Therefore, other technologies (such as...) can be used. Figure 5 The first solenoid valve 528 is fluidly connected to the first return box 512, instead of the above. Figure 1-4 The hydraulic actuation used for the bias valve is described. Additionally, it should be noted that power 530 can be supplied from other sources because... Figure 5 This is merely an example. In this configuration, a first fuel pump 520 pumps first fuel from a first fuel supply 506 into a first fuel rail 507. The first fuel travels from the first fuel rail 507 through a first outlet valve 522, a first fuel inlet line 524, and into an injector 502 for combustion. Excess first fuel exits the injector 502 through a first excess fuel line 526, enters an excess first fuel rail 540, and then enters a first return tank 512. Furthermore, in this configuration, an ignition fuel pump 514 pumps ignition fuel from an ignition fuel supply 504 into an ignition fuel rail 505. The ignition fuel exits the ignition fuel rail 505 through an ignition inlet line 516 and enters the injector 502 for combustion as ignition fuel. Excess ignition fuel exits through an excess ignition line 518, enters an excess ignition fuel rail 542, and then enters an ignition return tank 508.

[0037] To switch from a configuration supplying first fuel to injector 502 to a configuration using ignition fuel as the first fuel, the first fuel pump 520 is de-energized, thereby de-energizing power supply 530 and thus closing the first solenoid valve 528. Closing the first solenoid valve 528 fluidly disconnects the first return tank 512 from the first fuel excess line 526. Furthermore, in this configuration, ignition fuel is pumped by ignition fuel pump 514 into the ignition fuel rail 505. The ignition fuel exits the ignition fuel rail 505 and enters the ignition input line 516 of injector 502. The pressure of the ignition fuel relative to the first fuel opens the input valve 532 of the input bypass line 534 and closes the first outlet valve 522, thus fluidly connecting the ignition input line 516 to the first fuel input line 524 and fluidly disconnecting the first fuel supply 506 from the first fuel input line 524. The outlet bypass valve 536 of the outlet bypass line 538 remains closed by the pressure of the ignition excess line 518. Excess ignition fuel leaves through ignition excess line 518, enters ignition fuel excess rail 542, and then enters ignition return box 508. The first solenoid valve 528 is closed to prevent excess ignition fuel from leaving through the first fuel excess line 526.

[0038] As mentioned above, in some cases it may be desirable or necessary to purge the first fuel from certain parts of the system. In this way, Figure 5 System 500 is configured to purge a first fuel (e.g., methanol) from a portion of system 500. (See above) Figure 1-4 In the example system, when the biased check valve at the outlet of the first fuel excess line (e.g., Figure 1When the bias check valve 128 is closed, the first return tank is fluidly disconnected from the system. While this prevents ignition fuel from entering the first return tank, the first fuel can remain in both the first fuel inlet line 524 and the first fuel excess line 526. To initiate purging operations on the first fuel inlet line 524 and the first fuel excess line 526, the purge solenoid valve 544 is activated and opened. When open, ignition fuel pumped by the ignition fuel pump 514 also enters the first fuel inlet line 524 through the purge check valve 546. The pump purge check valve 548 prevents ignition fuel from flowing into the first fuel supply 506. The pump purge check valve 548 may be optional if it is desired to purge the first fuel also from the first fuel pump 520. The purge bias line 550 supplies fluid pressure from the purge solenoid valve 544 to the bias purge valve 552, which opens when the purge solenoid valve 544 is activated and opened. Therefore, in this configuration, the ignition fuel can be used to purge the first fuel (e.g., methanol) through the first fuel rail 507, the first fuel inlet line 524, the first excess fuel line 526, the first solenoid valve 528 (which remains open), through the excess first fuel rail 540, and into the first return tank 512. The purging operation can be completed by closing the purging solenoid valve 544, and the engine can be shut down.

[0039] Figure 6 A method 600 for an operating system 100, according to various examples of the currently disclosed subject matter, is shown, in which fuel switching at a cylinder can be performed. The methods 600 and other processes described herein are shown as example flowcharts, each of which may represent a sequence of operations whose order is not intended to be construed as limiting, and any number of said operations may be combined in any order and / or in parallel to implement said processes.

[0040] Method 600 begins at step 602, in which the system operates in a first configuration, whereby the ignition fuel pump 114 pumps ignition fuel through the ignition fuel inlet line 116 and into the injector 102 for combustion. Excess ignition fuel exits the injector 102 through the ignition excess line 118 and enters the ignition return tank 108. In the same configuration, the injector 102 receives a first fuel (e.g., methanol) from a first fuel supply 106. A first fuel pump 120 is in fluid communication with the first fuel supply 106 and pumps the first fuel through a first outlet valve 122, through the first fuel inlet line 124, and into the injector 102 for combustion. Excess first fuel exits the injector 102 through the first fuel excess line 126, through the biased check valve 128, and into the first return tank 112.

[0041] In order to change the operation of the system 100 in the first configuration, the method 600 continues to step 604, in which the first fuel pump 120 is de-energized, which reduces or decreases the flow of the first fuel from the first fuel supply 106.

[0042] The method continues to step 606, where the bias check valve 128 is closed to fluidly disconnect the first return tank 112 from the ignition fuel supply 104. When the first fuel pump 120 is energized, the bias line 130 from the first fuel inlet line 124 provides a bias pressure to the bias check valve 128 to keep it open. De-energizing the first fuel pump 120 reduces the bias pressure on the bias check valve 128, thereby allowing it to close. However, it should be noted that the subject matter disclosed herein is not limited to the use of bias pressure, as other methods can be used to fluidly connect and disconnect the first return tank from the first fuel supply. Figure 5 An example is provided in which a solenoid valve is used to fluidly connect and disconnect a first return tank from a first fuel supply.

[0043] With the bias check valve 128 closed in step 606, method 600 continues to step 608, in which the ignition fuel is used as the first fuel in the second configuration. In this configuration, the decrease in pressure in the bias line 130 from the first fuel inlet line 124 further allows the inlet valve 132 of the inlet bypass line 134 to open and allows the first outlet valve 122 to close, thus fluidly connecting the ignition fuel inlet line 116 to the first fuel inlet line 124 and fluidly disconnecting the first fuel supply 106 from the first fuel inlet line 124. Furthermore, the pressure from the first fuel excess line 126 opens the outlet bypass valve 136 of the outlet bypass line 138. Therefore, in this configuration, the first fuel is no longer received from the first fuel supply 106. Furthermore, ignition fuel is pumped into the ignition fuel inlet line 116 and into the injector 102 for combustion, and also pumped through the inlet valve 132 of the inlet bypass line 134, through the first fuel inlet line 124, and into the injector 102 for combustion. Excess ignition fuel is directed to the ignition return tank 108 through both the excess ignition line 118 and the outlet bypass valve 136 of the outlet bypass line 138, thereby fluidly disconnecting the first return tank 112 by closing the bias check valve 128.

[0044] To return to the first configuration, method 600 continues to step 610, in which the first fuel pump 120 is re-energized, which increases the flow of first fuel from the first fuel supply 106.

[0045] Method 600 continues to step 612, in which the bias check valve 128 is opened to fluidly connect the first return tank 112 to the ignition fuel supply 104. When the first fuel pump 120 is energized, the bias line 130 from the first fuel inlet line 124 provides bias pressure to the bias check valve 128 to open it. Method 600 then continues to step 602 in the first configuration.

[0046] Figure 7 This is a schematic diagram of an alternative injector system 700 using a second ignition fuel input for fuel switching at the cylinder of injector 702, based on various examples of the currently disclosed subject matter. It should be noted that, as Figure 7 The injector 702 shown is merely to illustrate fluid flow in a fuel switching configuration at the cylinder, because the injector 702 and other components shown herein may have additional features, parts, or structures not shown in this or other figures but which may be used otherwise. Figure 7 In the first configuration, injector 702 receives ignition fuel 704 and first fuel 706. Ignition fuel 704 is pumped by ignition fuel pump 708 into ignition fuel rail 710, ignition fuel inlet line 711, and then into injector 702. First fuel 706 is pumped by first fuel pump 712 through two-way first fuel inlet valve 714 into first fuel rail 716, first fuel inlet line 717, and then into injector 702.

[0047] As described above, the first fuel inlet valve 714 is a two-way solenoid valve. In the energized state (e.g., in the first position), the solenoid valve receives power, and the first fuel 706 is directed into the first fuel rail 716. In the de-energized state, the solenoid valve does not receive power, and the first fuel 706 is directed into the first fuel circuit 718. The first fuel circuit 718 is a fuel line that directs the first fuel 706 into a first fuel tank (not shown) for storing the first fuel 706. Continuing with the current configuration, unburned ignition fuel 704 exits the injector 702 via the ignition fuel excess line 719, enters the ignition fuel return rail 720, passes through the ignition fuel return check valve 722, and subsequently enters the ignition fuel circuit 724. Similar to the first fuel circuit 718, the ignition fuel circuit 724 is a fuel line that directs the ignition fuel 704 into an ignition fuel tank (not shown) for storing the ignition fuel 704. Unburned first fuel 706 exits the injector 702 via a first fuel excess line 725, enters a first fuel rail circuit 726, passes through a fluid mixture sensor 728, passes through a first return isolation valve 730, and subsequently enters a first fuel circuit 732. The first fuel circuit 732 is a fuel line that directs the first fuel 706 to a first fuel tank (not shown) for storing the first fuel 706. The first return isolation valve 730 is a two-way solenoid valve, whereby, in the energized state (or first position), unburned first fuel 706 is directed to the first fuel circuit 732. In the de-energized state (or second position), whereby the solenoid valve is not energized, unburned first fuel 706 is directed to a fuel bypass 734, which is used when ignition fuel 704 is supplied as both ignition fuel and first fuel, as explained in more detail below.

[0048] To switch from the first configuration, which supplies first fuel 706 to injector 702, to a second configuration, which uses ignition fuel 704 as both the first and ignition fuels, the first fuel pump 712 and the first fuel inlet valve 714 are de-energized (e.g., in the second position). De-energizing the first fuel inlet valve 714 directs its output from the first fuel rail 716 to the first fuel circuit 718 and closes the first outlet valve 736. With the first fuel pump 712 and the first fuel inlet valve 714 de-energized, the ignition fuel bypass valve 738 is energized from the closed first position (fluidly disconnecting ignition fuel 704) to the open second position, thereby fluidly connecting ignition fuel 704 to the first fuel inlet line 717. Thus, in the second position, a portion of the ignition fuel 704 is directed through the inlet bypass line 739, the ignition fuel bypass check valve 740, and into injector 702. The ignition fuel bypass check valve 740 opens as the pressure from the ignition fuel pump 708 and the first fuel pump 712 decreases. Therefore, in this configuration, ignition fuel 704 enters the injector 702 through both the ignition fuel rail 710 and the ignition fuel bypass check valve 740.

[0049] When switching to the second configuration, a portion of the first fuel 706 may still leave the injector 702. Therefore, in some examples, the switching of the first return isolation valve 730 from delivering the first fuel 706 to the first fuel circuit 732 may be delayed. As described above in the second configuration, the ignition fuel has replaced the first fuel in the injector 702. After a predetermined period of time, or when a sensor such as the fluid mixture sensor 728 senses that the fluid is primarily or entirely ignition fuel 704 (e.g., diesel), the first return isolation valve 730 is energized to direct fuel to the return bypass 741, the return bypass check valve 742, and the ignition fuel circuit 724.

[0050] Industrial applicability

[0051] This disclosure generally relates to internal combustion engines that use two fuels for combustion: a primary fuel such as methanol and an ignition fuel such as diesel. The system described herein allows for a switch from methanol to diesel as the primary fuel at the cylinder level, rather than at the system level. In some conventional systems, the switch from methanol to diesel is accomplished by switching the fuel entering the primary fuel rail. While the fuel ultimately entering the cylinders will switch from methanol to diesel, this can result in a time delay because diesel needs to move through the system and eventually reach all cylinders. During this transition, some cylinders may be receiving diesel fuel (as the primary fuel), some cylinders may be receiving a mixture of diesel and methanol, and some cylinders may still be receiving methanol. This situation can complicate engine timing and delay the delivery of the desired power increase.

[0052] The system described in this article reduces switching time by switching from one fuel to another at the cylinder level rather than at the system level. In some examples, the valve at the inlet of its corresponding first return tank (such as, for example, Figure 1 Valve 128 Figure 4 Valve 428 and Figure 5 Valve 528 isolates the first return tank. Additionally, the first fuel pump is de-energized, thereby allowing the input valve (e.g., Figure 3 The ignition inlet 214 (132) is opened, allowing ignition fuel to enter the injector 102 not only through the ignition fuel inlet 214 but also through the first fuel inlet 218. Therefore, the injector 102 switches from receiving fuel from the first fuel supply to receiving fuel from the ignition fuel supply, potentially reducing the time required to switch from using the first fuel to using the ignition fuel. This can reduce the time required to deliver the desired engine power by using ignition fuel instead of a fuel such as methanol as the first fuel.

[0053] Unless explicitly excluded, the use of the singular to describe a component, structure, or operation does not preclude the use of multiple 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 one of the following: A; B; C; A and B; A and C; B and C; A, B, and C; or multiple items such as A and A; B, B, and C; A, A, B, C, and C, etc.

[0054] While aspects of this disclosure have been specifically shown and described with reference to the foregoing embodiments, those skilled in the art will understand that various other embodiments can be conceived through modifications to the disclosed machines, systems, and methods without departing from the spirit and scope of the disclosure. Such embodiments should be understood to fall within the scope of this disclosure as defined by the claims and any equivalents.

Claims

1. A system (100) comprising: An internal combustion engine (208) that burns a first fuel (212) and an ignition fuel (210), wherein the engine (208) includes an injector (102) in a cylinder of the engine, the injector (102) being configured to inject the ignition fuel (210) and the first fuel (212) for combustion; A first fuel pump (120) is fluidly connectable to a first fuel supply (106) to supply the first fuel (212) to the injector (102) via a first fuel inlet line (124) and is fluidly disconnectable from the first fuel supply; Ignition fuel pump (114), which is fluidly connected to ignition fuel supply (104) to supply ignition fuel (210) to the injector (102) via ignition fuel inlet line (116). A first return isolation valve (730) is used to fluidly disconnect the first fuel excess line (126) from the first return tank (112) in a first position of the first return isolation valve (730) and to fluidly connect the first fuel excess line (126) in a second position of the first return isolation valve (730). A first outlet valve (122) is configured to fluidly connect the first fuel (212) to the first fuel inlet line (124) when the first outlet valve (122) is in a first position, and to fluidly disconnect the first fuel (212) from the first fuel inlet line (124) when the first outlet valve (122) is in a second position; and An input bypass line (134) is provided to supply a portion of the ignition fuel (210) from the ignition fuel pump (114) to the first fuel input line (124) when the first outlet valve (122) is in the second position of the first outlet valve (122).

2. The system (100) according to claim 1, wherein a first position of the bypass valve (136) fluidly disconnects the ignition fuel (210) from the first fuel input line (124), a second position of the bypass valve (136) fluidly connects the ignition fuel (210) to the first fuel input line (124) via the input bypass line (134) and the ignition fuel bypass valve (738), and wherein the bypass valve is in the first position when the first outlet valve (122) is in the first position, and the bypass valve is in the second position when the first outlet valve (122) is in the second position.

3. The system (100) of claim 1, wherein the input bypass line (134) includes an input valve to fluidly disconnect the ignition fuel supply (104) from the first fuel supply (106) when the first fuel pump (120) is energized and the first fuel (212) is pumped from the first fuel supply (106).

4. The system (100) of claim 1, wherein the first return isolation valve (730) includes a bias check valve that remains open by the outlet pressure of the first fuel pump (120) when the first fuel pump (120) is energized and pumping the first fuel (212) from the first fuel supply (106), and closes when the first fuel pump (120) is de-energized and not pumping the first fuel (212) from the first fuel supply (106).

5. The system (100) according to claim 1, wherein the first return isolation valve (730) comprises a normally closed electromagnetically activated valve powered by electricity, wherein when the first return isolation valve (730) is open, the normally closed electromagnetically activated valve fluidly connects the first return tank (112) to the first fuel excess line (126), and when the first return isolation valve (730) is closed, the normally closed electromagnetically activated valve fluidly disconnects the first return tank (112) from the first fuel excess line (126).

6. The system (100) according to claim 5, wherein the power is a portion of the power supplied to the first fuel pump (120), whereby when the first fuel pump (120) is de-energized, the power to the first return isolation valve (730) is removed, thereby closing the first return isolation valve (730).

7. The system (100) according to claim 1, further comprising an outlet bypass line (138) and an outlet bypass valve, wherein when the outlet bypass valve is open, the first fuel excess line (126) is fluidly connected to the ignition return box, and when the outlet bypass valve is closed, the first fuel excess line (126) is fluidly disconnected from the ignition return box.

8. The system (100) according to claim 1, wherein the ignition fuel (210) comprises diesel fuel, and the first fuel (212) comprises methanol.

9. The system (100) of claim 1 further includes a purge valve configured to fluidly connect the ignition fuel pump (114) to a first fuel rail when open, the first fuel rail receiving fuel for the first fuel inlet line (124).

10. An injector (102) system (100), comprising: Injector (102), the injector comprising: Ignition fuel inlet, the ignition fuel inlet being used to receive ignition fuel (210) from ignition fuel pump (114) fluidly connected to ignition fuel supply (104) via ignition fuel inlet line (116). Ignition fuel outlet, the ignition fuel outlet being used to remove excess ignition fuel (210) into the ignition return box; A first fuel inlet is used to receive fuel via a first fuel inlet line (124), wherein the fuel comprises: When the first outlet valve (122) of the first fuel pump (120) fluidly connected to the first fuel inlet line (124) is open, and when the inlet valve for supplying a portion of the ignition fuel (210) from the ignition fuel pump (114) to the inlet bypass line (134) in the first fuel inlet line (124) is closed, the first fuel (212) from the first fuel pump (120); or When the first outlet valve (122) is closed, and when the inlet valve is open, the ignition fuel (210) from the ignition fuel pump (114); and A first fuel outlet is used to remove excess fuel received in the first fuel inlet line (124) via a first excess fuel line (126).

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