Device and method for conditioning and injecting gaseous fuel into internal combustion engine

Abstract

An apparatus includes a pressure regulator, an in-cylinder fuel injector, and a controller programmed to, upon fueling with a first gaseous fuel, command the regulator to regulate a pressure of the first gaseous fuel to a first injection pressure, and commanding the injector to inject an injection amount of a first gaseous fuel into the combustion chamber at a first injection pressure within 90 CA DEG of the TDC during the compression stroke; and while refueling with the second gaseous fuel, commanding the regulator to regulate the pressure of the second gaseous fuel to a second injection pressure, and commanding the injector to inject an injection amount of the second injected gaseous fuel within 90 CA DEG of the TDC during the compression stroke.

Description

Technical Field

[0001] The present application relates to a device and a method for pressure regulating a gaseous fuel and injecting the gaseous fuel into an internal combustion engine. Background Art

[0002] Each document, reference, patent application or patent cited in this article is expressly incorporated herein by reference in its entirety, which means that the reader should read and consider it as part of this article. Documents, references, patent applications or patents cited in this article are not repeated in this article only for the sake of brevity.

[0003] The following discussion of the background of the invention is intended only to facilitate understanding of the invention. It should be understood that this discussion is not an acknowledgement or admission that any of the material referred to was published, known or part of the common general knowledge of a person skilled in the art in any jurisdiction at the priority date of the present invention.

[0004] Gas fuel direct injection (GFDI) is a technology for introducing high-pressure gaseous fuel into the combustion chamber of an internal combustion engine, wherein the gaseous fuel is directly injected into the combustion chamber near the second half of the compression stroke. Therefore, the injection pressure of the gaseous fuel needs to be greater than the pressure in the combustion chamber at the time of injection (also referred to as the in-cylinder pressure). GFDI engines are generally fueled by natural gas, which is stored in a liquefied form at a low temperature of about 112 Kelvin (K). A cryogenic pump pressurizes the liquefied natural gas that is fluidly transmitted through a heat exchanger to vaporize and change the state of the natural gas to a gaseous state or a supercritical state (the state is determined by the pressure and temperature of the vaporized natural gas). The gas fuel injection pressure used in the GFDI engine is about 300 bar. In an exemplary embodiment, the cryogenic pump pressurizes the liquefied and vaporized gaseous fuel to a value between, for example, 320 bar and 340 bar, so that the vaporized natural gas can be adjusted down to a final injection pressure of 300 bar. It is more efficient to pressurize natural gas in liquefied form than in vaporized form because in liquefied form, natural gas behaves like an incompressible fluid, whereas in vaporized form, natural gas is a compressible fluid. Pressurizing a compressible fluid, compared to an incompressible fluid, results in significant energy losses, which can reduce the fuel economy of a GFDI engine.

[0005] There is a renewed interest in the use of hydrogen as a fuel for internal combustion engines. Hydrogen is a carbon-free fuel and therefore does not produce carbon-based greenhouse gases (GHGs) such as carbon dioxide. Hydrogen is currently being used as a fuel in fuel cell applications, where the hydrogen is stored as a compressed gas at a maximum storage pressure of typically 700 bar. Hydrogen fuel cells typically operate at a hydrogen pressure of less than 5 bar, so that the storage pressure of the hydrogen is downregulated to this operating pressure value. Since hydrogen is stored as a compressed gas rather than in its liquefied form, the high value of the maximum storage pressure of 700 bar is selected to increase the storage density of the hydrogen to extend the range of fuel cell vehicles. Currently, liquefied hydrogen is significantly more expensive than natural gas, because the boiling point of hydrogen at atmospheric pressure is about 20.3 K (compared to the boiling point of natural gas of about 112 K) and the density of natural gas at standard temperature and pressure (STP) is 0.7 to 0.9 kg / m 3 Compared with the density of hydrogen at STP (0.0899 kg / m 3 ) is low; the density of natural gas is about one order of magnitude higher than the density of hydrogen. In the context of this application, standard temperature is 273.15K (0 degrees Celsius) and standard pressure is 1 atmosphere (atm). In addition, gaseous fuel refers to any fuel that is gaseous at standard temperature and pressure. Hydrogen and natural gas are typical gaseous fuels, in addition to biogas, ethane, methane, methane-rich gas from fossil or renewable resources, butane, propane or mixtures of these fuels.

[0006] The storage pressure of compressed hydrogen (CH2) decreases as fuel is consumed in a GFDI engine. Once the storage pressure drops below the injection pressure, e.g., 300 bar, the hydrogen must be compressed to maintain the injection pressure as the storage pressure drops to a lower pressure limit below which the engine cannot operate in the GFDI operating mode, at least not at the engine's optimal level. There is an energy loss in pressurizing the CH2 to the injection pressure, which increases significantly as the storage pressure reaches the lower pressure limit, and this parasitic energy loss reduces the fuel economy of the GFDI engine.

[0007] The prior art lacks the technology to pressure regulate gaseous fuel and inject the gaseous fuel into an internal combustion engine. The present apparatus and method provide technology for regulating gaseous fuel and injecting the gaseous fuel into an internal combustion engine. Summary of the invention

[0008] An improved device for regulating a first gas fuel and / or a second gas fuel and injecting the first gas fuel and / or the second gas fuel in an internal combustion engine, the device comprising a pressure regulator and an in-cylinder fuel injector. The pressure regulator regulates the pressure of the first gas fuel or the pressure of the second gas fuel. The in-cylinder fuel injector is fluidly connected to the pressure regulator to receive the first gas fuel or the second gas fuel and directly inject the first gas fuel or the second gas fuel into the combustion chamber of the internal combustion engine. There is also a controller, which is operably connected to the pressure regulator and the in-cylinder fuel injector, and the controller is programmed to: when the internal combustion engine is fueled with the first gas fuel, command the pressure regulator to regulate the pressure of the first gas fuel to a first injection pressure at the engine load and engine speed; and command the in-cylinder fuel injector to inject the injection amount of the first gas fuel into the combustion chamber at the first injection pressure within 90 degrees of crankshaft rotation angle of the top dead center during the compression stroke. When fueling the internal combustion engine with a second gaseous fuel, the controller is programmed to: command the pressure regulator to adjust the pressure of the second gaseous fuel to a second injection pressure at the same engine load and engine speed; and command the in-cylinder fuel injector to inject an injection amount of the second gaseous fuel (the injection amount of the second gaseous fuel may be the same or different from the injection amount of the first gaseous fuel) into the combustion chamber at a second injection pressure within 90 degrees of crankshaft rotation at top dead center during the compression stroke. In an exemplary embodiment, the first gaseous fuel includes a gaseous fuel having a hydrogen mole percentage (mol %) less than the second gaseous fuel; at the engine load and engine speed, the second injection pressure is less than the first injection pressure by a pressure value, and the injection amount of the first gaseous fuel and the injection amount of the second gaseous fuel are burned in a diffusion combustion mode. In some embodiments, the pressure value between the first injection pressure and the second injection pressure may be greater than 15 bar, in other embodiments, the pressure value may be greater than 20 bar, and in yet other embodiments, the pressure value may be greater than 25 bar, and the pressure value varies with fuel composition and / or engine operating requirements.

[0009] In another exemplary embodiment, the first gas fuel may include one of biogas, ethane, methane, natural gas, butane, propane, or a mixture of these fuels, and the second gas fuel may be hydrogen.

[0010] In yet another exemplary embodiment, the first gas fuel contains less than the mole percent of hydrogen contained in the second gas fuel. The first gas fuel may include less than 1 mole percent (mol%) of hydrogen, and the second gas fuel may include more than 1 mol% of hydrogen. In some embodiments, the second gas fuel may include at least 5 mol% of hydrogen; or the second gas fuel may include more than 15 mol% of hydrogen, or more than 25 mol% of hydrogen, or more than 40 mol% of hydrogen, or more than 50 mol% of hydrogen, or more than 70 mol% of hydrogen, or more than 90 mol% of hydrogen; or may be substantially hydrogen. The pressure value varies with the mole % of hydrogen in the second gas fuel; the pressure value may also vary with the type of the first gas fuel, and / or with the difference between the mole % of hydrogen in the second gas fuel and the mole % of hydrogen in the first gas fuel. In some embodiments, the first gas fuel may contain substantially 0 mol% of hydrogen. In some embodiments, the difference between the hydrogen mol% of the second gas fuel and the hydrogen mol% of the first gas fuel can be that the second gas fuel has 5 mol% or more hydrogen, or 15 mol% more hydrogen, or 25 mol% more hydrogen, or 40 mol% more hydrogen, or 50 mol% more hydrogen, or 70 mol% more hydrogen, or 90% more hydrogen than the first gas fuel. In some embodiments, the second gas fuel is substantially hydrogen, while in other embodiments, the second gas fuel contains hydrogen and may also include one of biogas, ethane, methane, natural gas, butane, propane, or a mixture of these fuels.

[0011] The device may also include a storage container for storing gaseous fuel. The compressor may be fluidly connected to the storage container, and the compressor is operable to compress the gaseous fuel from the storage container. There may be a bypass valve in fluid communication with the storage container, and the bypass valve is selectively commanded by the controller to be in a bypass position to fluidly transfer the gaseous fuel from the storage container around the compressor, and to be in a blocking position to allow the gaseous fuel from the storage container to be fluidly transferred through the compressor. The storage container stores the gaseous fuel as compressed gas, and the gaseous fuel is a first gaseous fuel or a second gaseous fuel, and the in-cylinder fuel injector fluidly receives the gaseous fuel from the compressor or the bypass valve. When the gaseous fuel is the first gaseous fuel, the controller may be programmed to: when the pressure of the gaseous fuel in the storage container is greater than or equal to the first injection pressure, command the bypass valve to be in a bypass position to fluidly transfer the gaseous fuel around the compressor. When the gaseous fuel is the second gaseous fuel, the controller may be programmed to: when the pressure of the gaseous fuel in the storage container is greater than or equal to the second injection pressure, command the bypass valve to be in a bypass position to fluidly transfer the gaseous fuel around the compressor. When the gaseous fuel is a first gaseous fuel, the controller may be programmed to command the bypass valve to be in a blocking position to allow the gaseous fuel from the storage container to be fluidly passed through the compressor when the pressure of the gaseous fuel in the storage container and / or the supply pressure upstream of the compressor is less than the first injection pressure. When the gaseous fuel is a second gaseous fuel, the controller may be programmed to command the bypass valve to be in a blocking position to allow the gaseous fuel from the storage container to be fluidly passed through the compressor when the pressure of the gaseous fuel in the storage container and / or the supply pressure upstream of the compressor is less than the second injection pressure.

[0012] A sensor such as a hot wire sensor may be disposed in a conduit between the storage container and the in-cylinder fuel injector, and the sensor is operably connected to the controller. In the example of a hot wire sensor, the hot wire sensor generates a temperature signal representing the gaseous fuel in the storage container as the gaseous fuel flows through the hot wire sensor, wherein the controller is programmed to receive the temperature signal and determine whether the gaseous fuel is a first gaseous fuel or a second gaseous fuel. The controller may also be programmed to determine the mole % of hydrogen in the first gaseous fuel and / or the second gaseous fuel. Alternatively or additionally, there may be a switch operable between a first position and a second position, and the switch is operably connected to the controller, which may be programmed to receive a signal from the switch, wherein when the switch is in the first position, the signal represents the first gaseous fuel, and when the switch is in the second position, the signal represents the second gaseous fuel.

[0013] In yet other embodiments, the apparatus may include a first storage container for storing a first gas fuel, a first shut-off valve, a second storage container, a second shut-off valve, and a compressor, the first storage container for storing a first gas fuel, the first shut-off valve for selectively fluidly transferring the first gas fuel from the first storage container, the second storage container for storing a second gas fuel, the second shut-off valve for selectively fluidly transferring the second gas fuel from the second storage container, the compressor being fluidly connected to the first shut-off valve and the second shut-off valve, and the compressor being operable to compress the gas fuel from the first storage container and / or the second storage container. A bypass valve may be fluidly connected to the first shut-off valve and / or the second shut-off valve, and the bypass valve may be selectively commanded by a controller to be in a bypass position to fluidly transfer the first gas fuel from the first storage container or the second gas fuel from the second storage container around the compressor, respectively, and the bypass valve may be selectively commanded by the controller to be in a blocking position to fluidly transfer the first gas fuel from the first storage container or the second gas fuel from the second storage container through the compressor. The controller may be programmed to command the first shut-off valve to open when fueling with the first gas fuel, and to command the second shut-off valve to open when fueling with the second gas fuel. The second storage container may store the second gaseous fuel as a compressed gas, and the in-cylinder fuel injector fluidly receives the first gaseous fuel or the second gaseous fuel from the compressor or the bypass valve. When fueling with the second gaseous fuel, the controller may be programmed to command the bypass valve to a bypass position to fluidly pass the second gaseous fuel from the second storage container around the compressor when the pressure of the second gaseous fuel in the second storage container is greater than or equal to the second injection pressure, and to command the bypass valve to a blocking position to fluidly pass the second gaseous fuel from the second storage container through the compressor when the pressure of the second gaseous fuel in the second storage container and / or the supply pressure upstream of the compressor is less than the second injection pressure.

[0014] The first storage container may store the first gaseous fuel as a liquefied gas or a compressed gas. When fueling with the first gaseous fuel, the controller may be programmed to command the bypass valve to a bypass position to fluidly pass the first gaseous fuel from the first storage container around the compressor when the pressure of the first gaseous fuel in the first storage container and / or the supply pressure upstream of the compressor is greater than or equal to the first injection pressure, and to command the bypass valve to a blocking position to fluidly pass the first gaseous fuel from the first storage container through the compressor when the pressure of the first gaseous fuel in the first storage container and / or the supply pressure upstream of the compressor is less than the first injection pressure.

[0015] For embodiments having more than one storage container, the second storage container may store the second gaseous fuel as a liquefied gas, a compressed gas, or a cryogenic compressed gas. During fueling with the second gaseous fuel, the controller may be programmed to command the bypass valve to a bypass position to fluidly pass the second gaseous fuel from the second storage container around the compressor when the pressure of the second gaseous fuel in the second storage container and / or the supply pressure upstream of the compressor is greater than or equal to the second injection pressure, and to command the bypass valve to a blocking position to fluidly pass the second gaseous fuel from the second storage container through the compressor when the pressure of the second gaseous fuel in the second storage container and / or the supply pressure is less than the second injection pressure.

[0016] An improved method for regulating and injecting a first gaseous fuel and / or a second gaseous fuel in an internal combustion engine, the method comprising: regulating the pressure of the first gaseous fuel to a first injection pressure at an engine load and engine speed when fueling the internal combustion engine with the first gaseous fuel; and injecting an injection amount of the first gaseous fuel into a combustion chamber at a first injection pressure within 90 degrees of crankshaft rotation at top dead center during a compression stroke of the engine; and regulating the pressure of the second gaseous fuel to a second injection pressure at an engine load and engine speed when fueling the internal combustion engine with the second gaseous fuel; and injecting an injection amount of the second gaseous fuel into the combustion chamber at a second injection pressure within 90 degrees of crankshaft rotation at top dead center during a compression stroke of the engine. In an exemplary embodiment, the first gaseous fuel contains less hydrogen mole % than the second gaseous fuel, and at an engine load and engine speed, the second injection pressure is less than the first injection pressure by a pressure value, and the injection amount of the first gaseous fuel and the injection amount of the second gaseous fuel are burned in a diffusion combustion mode. In another exemplary embodiment, the first gaseous fuel includes a gaseous fuel other than hydrogen, and the second gaseous fuel may include a range up to substantially 100 mol % hydrogen, and at an engine load and engine speed, the second injection pressure is less than the first injection pressure by a pressure value, and the injected amount of the first gaseous fuel and the injected amount of the second gaseous fuel are combusted in a diffusion combustion mode.

[0017] An improved device for regulating gaseous fuel and injecting the gaseous fuel in an internal combustion engine, the device comprising a pressure regulator and an in-cylinder fuel injector. The pressure regulator regulates the pressure of the gaseous fuel. The in-cylinder fuel injector fluidly receives the gaseous fuel from the pressure regulator and injects the gaseous fuel directly into the combustion chamber of the internal combustion engine. There is also a controller, which is operably connected to the pressure regulator and the in-cylinder fuel injector, and the controller is programmed to: command the pressure regulator to regulate the pressure of the gaseous fuel to an injection pressure under engine load and engine speed, and command the in-cylinder fuel injector to inject an injection amount of gaseous fuel into the combustion chamber at the injection pressure within 90 degrees of crankshaft rotation of the top dead center during the compression stroke. In an exemplary embodiment, the gaseous fuel includes hydrogen, the injection pressure is equal to the product of the in-cylinder peak pressure multiplied by a multiplication factor, the multiplication factor is in the range of 1.15 to 1.4, and the injection amount is burned in a diffusion combustion mode. In other embodiments, the multiplication factor is in the range of 1.16 to 1.3, and in still other embodiments, the multiplication factor is in the range of 1.17 to 1.25. In some embodiments, the gaseous fuel is greater than 15 mol% hydrogen, or greater than 30 mol% hydrogen, or greater than 45 mol% hydrogen, or greater than 60 mol% hydrogen, or greater than 75 mol% hydrogen, or greater than 90 mol% hydrogen. In some embodiments, the gaseous fuel is substantially hydrogen.

[0018] An improved method for regulating gaseous fuel and injecting the gaseous fuel in an internal combustion engine, the method comprising regulating the pressure of the gaseous fuel to an injection pressure at an engine load and engine speed, and injecting an injection amount of the gaseous fuel into a combustion chamber at the injection pressure within 90 degrees of the top dead center during the compression stroke. In an exemplary embodiment, the gaseous fuel comprises hydrogen, the injection pressure is equal to the product of the peak pressure in the cylinder multiplied by a multiplication factor, the multiplication factor is in the range of 1.15 to 1.4, and the injection amount is burned in a diffusion combustion mode. In other exemplary embodiments, the multiplication factor is in the range of 1.16 to 1.3, and in yet other exemplary embodiments, the multiplication factor is in the range of 1.17 to 1.25. In some embodiments, the gaseous fuel is more than 15 mol% hydrogen, or more than 30 mol% hydrogen, or more than 45 mol% hydrogen, or more than 60 mol% hydrogen, or more than 75 mol% hydrogen, or more than 90 mol% hydrogen. In other embodiments, the gaseous fuel is essentially hydrogen.

[0019] In a gas fuel internal combustion engine system, gas fuel is stored as compressed gas in a storage container, and a pressure sensor sends a signal representing a supply pressure in the storage container. A compressor is fluidly connected to the storage container to pressurize the gas fuel, and a bypass valve is fluidly connected to the storage container to fluidly bypass the compressor when the bypass valve is in an open position. There is a gas fuel rail that is fluidly connected to the downstream side of the compressor and the downstream side of the bypass valve, wherein the gas fuel has an injection pressure in the gas fuel rail. An in-cylinder fuel injector is fluidly connected to the gas fuel rail, and the in-cylinder fuel injector is operable to introduce the gas fuel directly into a combustion chamber of the internal combustion engine. An improved method for regulating gas fuel and injecting the gas fuel in an internal combustion engine, the method comprising: determining the supply pressure based on the signal representing the supply pressure; and determining a desired injection pressure based on engine load and engine speed conditions. When the supply pressure is greater than or equal to the desired injection pressure, the method includes: opening the bypass valve to fluidly transfer the gas fuel from the storage container to the gas fuel rail bypassing the compressor. When the supply pressure is less than the desired injection pressure, the method includes: closing the bypass valve so that the compressor pressurizes the gaseous fuel from the storage container to the desired injection pressure. The method also includes: determining injection parameters based on the injection pressure; and actuating the in-cylinder injector to introduce the gaseous fuel into the combustion chamber.

[0020] An improved device for regulating gaseous fuel and injecting the gaseous fuel in an internal combustion engine, the device having a storage container, a compressor, a bypass valve, a gaseous fuel rail, an in-cylinder fuel injector, a first pressure sensor, a second pressure sensor, and a controller, the storage container storing the gaseous fuel as compressed gas, the compressor being fluidly connected to the storage container to pressurize the gaseous fuel, the bypass valve being fluidly connected to the storage container and being actuatable between a closed position and an open position to bypass the compressor, the gaseous fuel rail being fluidly connected to an output end of the compressor and an output end of the bypass valve, the gaseous fuel being in the gaseous fuel rail The invention relates to an internal combustion engine having an injection pressure in a gaseous fuel rail, an in-cylinder fuel injector fluidly connected to a gaseous fuel rail and the in-cylinder fuel injector can be actuated to introduce fuel directly into a combustion chamber of an internal combustion engine, a first pressure sensor sends a signal representing a supply pressure in a storage container or a supply pressure in a supply conduit of a storage container fluidly connected to an upstream of a compressor, a second pressure sensor is fluidly connected to a downstream side of the compressor and a downstream side of a bypass valve, and the second pressure sensor sends a signal representing a rail injection pressure of the gaseous fuel, and a controller is operably connected to the bypass valve, the in-cylinder fuel injector, the first pressure sensor, and the second pressure sensor. The controller is programmed to: receive a signal representing the supply pressure and a signal representing the rail injection pressure; determine the supply pressure of the gaseous fuel based on the signal representing the supply pressure; determine a desired injection pressure based on engine load and engine speed conditions; and determine the rail injection pressure of the gaseous fuel based on the signal representing the rail injection pressure. When the supply pressure is greater than or equal to the desired injection pressure, the controller actuates the bypass valve to be in an open position; determines an injection parameter based on at least one of the supply pressure and the rail injection pressure; and actuates the in-cylinder fuel injector to introduce fuel into the combustion chamber. When the supply pressure is less than the desired injection pressure, the controller actuates the bypass valve to be in a closed position, whereby the compressor pressurizes the gaseous fuel to the desired injection pressure; and the controller also determines the injection parameters according to the rail injection pressure; and actuates the in-cylinder fuel injector to introduce the fuel into the combustion chamber. The controller can also be programmed to command the in-cylinder fuel injector to inject the injection amount of gaseous fuel into the combustion chamber at an injection pressure within 90 degrees of the top dead center during the compression stroke of the engine. The controller can also be programmed to command the in-cylinder fuel injector to inject the injection amount of gaseous fuel into the combustion chamber at an injection pressure within 45 degrees of the top dead center during the compression stroke of the engine. In some embodiments, the pilot fuel ignites the gaseous fuel. Some embodiments have a forced ignition source, and in those embodiments, the controller can also be programmed to: command the in-cylinder fuel injector to inject directly into the combustion chamber during the intake stroke of the engine, or command the in-cylinder fuel injector to inject within 90 degrees of the crankshaft angle after the bottom dead center during the compression stroke of the engine. The gaseous fuel may include at least one of hydrogen, biogas, ethane, methane, natural gas, butane, propane, or a mixture of these fuels.In some embodiments, the gaseous fuel comprises more than 5 mol% hydrogen, or more than 15 mol% hydrogen, and in some embodiments, the gaseous fuel comprises more than 30 mol% hydrogen. In some embodiments, the gaseous fuel comprises more than 45 mol% hydrogen, and in some embodiments, the gaseous fuel comprises more than 60 mol% hydrogen. In some embodiments, the gaseous fuel comprises more than 75 mol% hydrogen, and in other embodiments, the gaseous fuel comprises more than 90 mol% hydrogen. In some embodiments, the gaseous fuel is substantially hydrogen.

[0021] An improved method for regulating gaseous fuel and injecting the gaseous fuel in an internal combustion engine, the method comprising gaseous fuel stored as compressed gas in a storage container and a first pressure sensor, the first pressure sensor emitting a signal indicative of a supply pressure in the storage container or a supply pressure in a supply conduit of the storage container fluidly connected upstream of a compressor. The compressor is fluidly connected to the storage container to pressurize the gaseous fuel, and a bypass valve is fluidly connected to the storage container to fluidly bypass the compressor when the bypass valve is in an open position. A gaseous fuel rail is fluidly connected to the downstream side of the compressor and the downstream side of the bypass valve, and a second pressure sensor is fluidly connected to the downstream side of the compressor and the downstream side of the bypass valve. The second pressure sensor emits a signal indicative of a rail injection pressure of the gaseous fuel. An in-cylinder injector is fluidly connected to the gaseous fuel rail and the in-cylinder injector is operable to introduce gaseous fuel directly into a combustion chamber of the internal combustion engine. The method comprises: determining the storage pressure and / or the supply pressure based on the signal indicative of the supply pressure upstream of the compressor; and determining a desired injection pressure based on engine load and engine speed conditions. When the supply pressure is greater than or equal to the desired injection pressure, the bypass valve is opened to bypass the compressor to fluidly deliver the gaseous fuel from the storage container to the gaseous fuel rail; and when the supply pressure is less than the desired injection pressure, the bypass valve is closed so that the compressor pressurizes the gaseous fuel to the desired injection pressure. The method also includes: determining a rail injection pressure of the gaseous fuel based on a signal representing the rail injection pressure; and determining injection parameters based on the rail injection pressure; and then actuating the in-cylinder injector to introduce the gaseous fuel into the combustion chamber. In some embodiments, the method may also include: determining a mole percentage of hydrogen in the supplied fuel, and adjusting the desired injection pressure to a first desired injection pressure that is lower than the first gaseous fuel at the same engine load and engine speed. The first gaseous fuel contains a lower mole % of hydrogen than the fuel supplied to the internal combustion engine. In other embodiments, the mole % of hydrogen of the fuel supplied to the internal combustion engine is known by the controller or otherwise predetermined, and the desired injection pressure for the engine load and engine speed can be directly provided by, for example, a fuel-specific lookup table and a fueling map. In some embodiments, the desired injection pressure of the gaseous fuel comprising a greater mole % of hydrogen for fueling the internal combustion engine may be reduced by a pressure value based on the desired injection pressure of the gaseous fuel having less mole % of hydrogen or even substantially 0 mole % of hydrogen for the same engine load and engine speed. In some embodiments, the method may further include injecting the injection amount of gaseous fuel into the combustion chamber within 90 degrees of crankshaft rotation of top dead center during the compression stroke of the engine. In some embodiments, the method may further include injecting directly into the combustion chamber during the intake stroke of the engine, or injecting within 90 degrees of crankshaft rotation after bottom dead center during the compression stroke of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated into and constitute a part of the specification, illustrate specific embodiments of the apparatus, system and method and, together with the above general description and detailed description of the specific embodiments, serve to explain the principles of the apparatus, system and method.

[0023] Figure 1 is a schematic diagram of a fuel system of an internal combustion engine according to an embodiment.

[0024] Figure 2 is a schematic diagram of a fuel system of an internal combustion engine according to another embodiment.

[0025] Figure 3 is a schematic diagram of a fuel system of an internal combustion engine according to another embodiment.

[0026] Figure 4 is a schematic diagram of a fuel system of an internal combustion engine according to another embodiment.

[0027] Figure 5 is a schematic diagram of an alternative arrangement for storing two types of gaseous fuels which may be used Figure 1 , Figure 2 , Figure 3 and Figure 4 in the fuel system.

[0028] Figure 6 is a schematic diagram of an alternative arrangement for storing two types of gaseous fuels which may be used Figure 1 , Figure 2 , Figure 3 and Figure 4 in the fuel system.

[0029] Figure 7a is a schematic diagram of an alternative arrangement for storing a gaseous fuel which may be used Figure 1 , Figure 2 , Figure 3 and Figure 4 in the fuel system.

[0030] Figure 7b is a schematic diagram of an alternative arrangement for storing a gaseous fuel which may be used Figure 1 , Figure 2 , Figure 3 and Figure 4 in the fuel system.

[0031] Figure 7c is a schematic diagram of an alternative arrangement for storing a gaseous fuel which may be used Figure 1 , Figure 2 , Figure 3 and Figure 4in the fuel system.

[0032] Figure 7d is a schematic diagram of an alternative arrangement for storing a gaseous fuel which may be used Figure 1 , Figure 2 , Figure 3 and Figure 4 in the fuel system.

[0033] Figure 8a is used for Figure 1 , Figure 2 , Figure 3 and Figure 4 Schematic diagram of the fuel type switch of the fuel system.

[0034] Figure 8b is a schematic diagram of a hot wire sensor configured in a gas fuel conduit, the hot wire sensor being used to detect Figure 1 , Figure 2 , Figure 3 and Figure 4 The type of fuel in the fuel system.

[0035] Fig. 9 is a flowchart of the algorithm used to Figure 1 , Figure 2 , Figure 3 and Figure 4 The first gas fuel and / or the second gas fuel in the fuel system are pressure regulated and injected.

[0036] Fig.10 is a flowchart of the algorithm used to Figure 1 , Figure 2 , Figure 3 and Figure 4 The hydrogen in the fuel system is pressure regulated and injected.

[0037] Fig.11 is a graphical view of the adiabatic flame temperature for methane and hydrogen versus the fuel / air equivalence ratio.

[0038] Fig.12 is a graphical view of the laminar flame speed for methane and hydrogen versus the fuel / air equivalence ratio.

[0039] Fig.13 yes Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 A graphical representation of storage vessel pressure versus time of an embodiment.

[0040] Fig.14 yes Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 A graphical view of the relationship between injection pressure and time of an embodiment.

[0041] Fig.15 is a flowchart of the algorithm used to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 An embodiment of the invention selects between dynamic injection pressure operation and static injection pressure operation. DETAILED DESCRIPTION

[0042] Although specific embodiments are given in the drawings and the following description, please keep in mind that the specific embodiments do not limit the present disclosure. Instead, these specific embodiments provide a basis for those of ordinary skill in the art to identify alternative forms, equivalents, and modifications covered within the scope of the appended claims. In addition, it should be noted that the embodiments and features of the embodiments in this application can be combined with each other without conflict.

[0043] Throughout the specification and claims, the following terms have the meanings clearly associated herein, unless the context clearly specifies otherwise. As used herein, the phrases "in one embodiment", "in some embodiments", "in exemplary embodiments" and "in some exemplary embodiments" do not necessarily refer to one or more identical embodiments, but they may refer to one or more identical embodiments. In addition, as used herein, the phrases "in other exemplary embodiments", "in alternative embodiments" and "in other embodiments" do not necessarily refer to different embodiments, but they may refer to different embodiments. Therefore, as described below, without departing from the scope of the present invention, various embodiments of the present invention can be easily combined.

[0044] The term "and / or" is used herein to mean "one or the other or both". In addition, as used herein, the term "or" is an inclusive "or" operator and is equivalent to the term "and / or", unless the context clearly dictates otherwise. The term "based on" is not exclusive and allows for being based on additional factors that are not described, unless the context clearly dictates otherwise. In addition, throughout the specification, the meanings of "a", "an" and "the" include plural references, unless the context clearly dictates otherwise. The phrase "the difference between X and Y" should be interpreted as "X minus Y", and "the difference between Y and X" should be interpreted as "Y minus X". The term "substantially" when modifying a parameter with a specified limit should be interpreted as meaning that a parameter actually has the same properties as the specified limit or achieves the same function as the specified limit, and includes the exact specified limit and those values ​​with slight deviations from the specified limit.

[0045] In order to simplify the present disclosure, various features may be combined together in the example embodiments, but this method of disclosure should not be interpreted as reflecting the following intention: any claimed embodiment requires more features than the features explicitly stated in the corresponding claims. On the contrary, the subject matter of the invention may be less than all the features of a single disclosed example embodiment, or the subject matter of the invention may combine features from different drawings or different embodiments. Therefore, the attached claims are incorporated into the detailed description herewith, wherein each claim exists independently as a separately disclosed embodiment. However, the present disclosure should also be interpreted as implicitly disclosing any embodiment having any suitable group (i.e., a set of features that are neither compatible nor mutually exclusive) of one or more disclosed or claimed features appearing in the present disclosure or the attached claims, including those groups that may not be explicitly disclosed herein or may not be explicitly disclosed in a single figure or embodiment. On the contrary, the scope of the attached claims does not necessarily cover the entire content of the subject matter disclosed herein.

[0046] Reference Figure 1, illustrates a fuel system 101 for regulating gaseous fuel pressure and injecting the gaseous fuel into a combustion chamber 111 in an internal combustion engine 121 according to one embodiment. The storage container 130 may be a pressure cylinder that stores the gaseous fuel as compressed gas. Typical storage pressures are 300 bar and 700 bar, at which the refueling station may pressurize the storage container 130; however, higher, lower, and other refueling storage pressures in between are also contemplated. The pressure regulator 141 may be in fluid communication with the storage container 130 to receive the gaseous fuel at the storage pressure and regulate the pressure of the gaseous fuel to the injection pressure. The accumulator 150 may store a desired volume of pressurized gaseous fuel at the injection pressure as a buffer to the fuel demand from the internal combustion engine 121, and the accumulator 150 may be a pipe or container of appropriate size that supplies the fuel from the pressure regulator 141. When the internal combustion engine 121 is shut down, the shut-off valve 160 may be used to isolate the accumulator 150 from the gaseous fuel rail 170 and the downstream fuel system. When a large amount of gaseous fuel flows through the shut-off valve, a small pressure drop may exist across the shut-off valve 160; however, this pressure drop is negligible compared to the value of the injection pressure.

[0047] The fuel injector 180 is fluidly connected to the gaseous fuel rail 170 and is operable to inject gaseous fuel directly into the combustion chamber 111. In an exemplary embodiment, the fuel injector 180 is hydraulically actuated to inject gaseous fuel into the combustion chamber 111 late during the compression stroke of the internal combustion engine 121, for example, before top dead center (TDC) and after 90 degrees of crankshaft angle (CA°). Although only one such fuel injector 180 is illustrated, in other embodiments, there may be multiple fuel injectors associated with corresponding combustion chambers. The gaseous fuel injected into the combustion chamber 111 may be ignited using conventional ignition techniques. The electronic controller 191 is operably connected to the pressure regulator 141, the shut-off valve 160, and the fuel injector 180 to command the operation of the pressure regulator 141, the shut-off valve 160, and the fuel injector 180. The pressure sensor 200 generates a signal indicative of a supply pressure that is substantially the same as the storage pressure of the gaseous fuel in the storage container 130. The pressure sensor 210 generates a signal indicative of a delivery pressure or rail injection pressure that is substantially the same as the injection pressure of the gaseous fuel in the gaseous fuel rail 170. The electronic controller 191 is operably connected to the first pressure sensor 200 and the second pressure sensor 210 to receive the signal indicative of the supply pressure and the signal indicative of the delivery pressure, respectively, and the electronic controller 191 is programmed to determine the supply pressure and the delivery (rail injection) pressure accordingly. In addition to the pressure sensors described herein, one or more temperature sensors may similarly be employed to generate a signal indicative of temperature, the one or more temperature sensors being integrated or separate from the disclosed pressure sensors, in which case the controller is also operably connected to the one or more temperature sensors to receive the signal indicative of temperature from the one or more temperature sensors, and the controller is programmed to determine the temperature of the fluid flowing through the one or more temperature sensors.

[0048] Reference Figure 2, shows a fuel system 102 according to another embodiment for regulating gaseous fuel and injecting the gaseous fuel into a combustion chamber 112 in an internal combustion engine 122, wherein similar components to the previous embodiment and other embodiments have similar reference numerals and only the differences are discussed. The pressure regulator 142 includes a compressor 220 and a bypass valve 230, each of which is fluidly connected to the storage container 130 to receive the gaseous fuel from the storage container 130 on the input side, and the compressor 220 and the bypass valve 230 are fluidly connected to the accumulator 150 to supply the gaseous fuel to the accumulator 150 on the output side. When the bypass valve 230 and the shut-off valve 160 are open, the injection pressure in the gaseous fuel rail 170 is substantially equal to the storage pressure in the storage container 130, wherein those skilled in the art understand that when the gaseous fuel flows through each of the valves 160 and 230, there may be a slight pressure drop through each of the valves 160 and 230. In this case, the supply pressure, which is also the storage pressure in the storage container 130, is greater than or equal to the desired injection pressure, so that the compressor 220 does not need to pressurize the gaseous fuel from the storage container 130. When the bypass valve 230 is closed, the shut-off valve 160 is opened, and the compressor 220 pressurizes the gaseous fuel received from the storage container 130 into the accumulator 150 and the gaseous fuel rail 170, the injection pressure in the gaseous fuel rail 170 is controlled by the compressor 220. In this case, the compressor 220 pressurizes the gaseous fuel received from the storage container 130 to the delivery pressure, which is also the injection pressure in the accumulator 150 and the gaseous fuel rail 170. The electronic controller 192 can be operably connected to the compressor 220 to command the operation of the compressor 220, especially in the case where the compressor 220 is electrically driven or hydraulically driven, in which case the electrical switch (not shown) and the mechanical valve (not shown) can be commanded by the controller 192 to selectively apply electrical energy and hydraulic energy to the compressor 220, respectively. In other embodiments, compressor 220 may be driven by an engine power take-off or camshaft of internal combustion engine 122, in which case a clutch (not shown) controlled by controller 192 may be used to turn the compressor on and off. Electronic controller 192 commands bypass valve 230 to open or close.

[0049] The forced ignition source 240 ignites the gaseous fuel injected by the fuel injector 180 into the combustion chamber 112. The controller 192 is operably connected to the forced ignition source 240 to actuate the forced ignition source to produce an ignition event within the combustion chamber 112. The forced ignition source 240 may be a spark igniter, a heated surface such as a glow plug, a corona discharge igniter, an induction heating igniter, or other types of forced ignition sources.

[0050] Reference Figure 3 , shows a fuel system 103 according to another embodiment for regulating gaseous fuel and injecting the gaseous fuel into a combustion chamber 112 in an internal combustion engine 122. A pressure regulator 143 regulates the pressure of the gaseous fuel in the accumulator 150 (referred to as the accumulator pressure) to a delivery pressure, which is the injection pressure found in the gaseous fuel rail 170. In an exemplary embodiment, the pressure regulator 143 may be a mechanical regulator that regulates the accumulator pressure to one output pressure (i.e., one injection pressure). There may be one mechanical regulator in the pressure regulator 143 so that there is a single injection pressure employed by the fuel system 103, or there may be more than one mechanical regulator in the pressure regulator 143, each with its own output pressure, whereby the controller 193 may select which of these pressure regulators to enable by selectively enabling and disabling the corresponding shut-off valve (not shown), so that there may be two or more injection pressures. When there is only one mechanical pressure regulator 143, the mechanical pressure regulator 143 may not be connected to the electronic controller 193, because the pressure regulator can be designed to adjust a range of input pressures to an output pressure without external control. In other embodiments, the pressure regulator 143 can be an electronically controlled regulator that is operably connected to the controller 193 and controlled by the controller 193 to adjust the output pressure of the electronically controlled regulator to two or more pressures. These electronically controlled regulators are also called servo-controlled regulators. In other embodiments, the pressure regulator 143 can be an injector that is controlled by the electronic controller 193 to inject discrete amounts of gaseous fuel into the gaseous fuel rail 170, whereby the electronic controller monitors the pressure in the gaseous fuel rail 170 to determine whether to actuate the injector to introduce more fuel mass into the gaseous fuel rail. In the illustrated embodiment, when the compressor 220 is disabled and the bypass valve 230 is open, the pressure regulator 143 regulates the gaseous fuel at the supply pressure from the storage container 130 to the delivery pressure or injection pressure in the gas fuel rail 170. When the compressor 220 is enabled and the bypass valve 230 is disabled, the pressure regulator 143 regulates the gaseous fuel at the accumulator pressure in the accumulator 150 to the delivery pressure (injection pressure) in the gas fuel rail 170. In this case, the compressor 220 pressurizes the gaseous fuel at the supply pressure in the storage container 130 to the gaseous fuel at the accumulator pressure in the accumulator 150. The pressure sensor 250 generates signals representing the accumulator pressure of the gaseous fuel in the accumulator 150, and the pressure sensor 250 sends these signals to the electronic controller 192 so that the electronic controller can determine the accumulator pressure and thereby more intelligently command the operation of the compressor 220.

[0051] Now refer to Figure 4 , shows a fuel system 104 according to another embodiment, which is used to regulate gaseous fuel and inject the gaseous fuel into the combustion chamber 114 in the internal combustion engine 124. In the illustrated embodiment, liquid fuel is used as a pilot fuel to ignite the gaseous fuel in the combustion chamber 114. The pumping device 260 pressurizes the pilot fuel from the pilot fuel storage container 270, and the pumping device 260 delivers the pressurized pilot fuel to the pressure regulator 144. In addition to other fuel system components known to those skilled in the art, the pumping device 260 may also include a transfer pump, an inlet metering valve, and a common rail pump located in the pilot fuel storage container 270. Generally, the pilot fuel is easier to ignite than the main fuel (herein, the gaseous fuel), and the pilot fuel is used to ignite the main fuel. The exemplary gaseous fuel used in the conventional GFDI engine is not automatically ignitable in the pressure and temperature environment prevalent in the second half of the compression stroke of the internal combustion engine. Therefore, a pilot fuel such as diesel fuel can be used as an ignition source to ignite the gaseous fuel. The pilot fuel may be injected during the compression stroke into a pressure and temperature environment that causes the pilot fuel to automatically ignite and burn, thereby establishing another pressure and temperature environment suitable for igniting the gaseous fuel. In an exemplary embodiment, the pilot fuel is injected late in the compression stroke so that the pilot fuel burns in a diffusion combustion mode. The gaseous fuel may be injected before the pilot fuel injection, during the pilot fuel injection, and / or after the pilot fuel injection. In other embodiments, the pilot fuel may be another gaseous fuel that is easier to ignite than the main gaseous fuel, so that the second gaseous fuel may be ignited by the pressure and temperature environment that exists during the compression stroke of the internal combustion engine, and more particularly the second gaseous fuel may be ignited by the pressure and temperature environment that exists in the second half of the compression stroke of the internal combustion engine. Back Figure 4 , the pressure sensor 300 generates signals representing the pilot fuel pressure downstream of the pumping device 260 and upstream of the pressure regulator 144, and these signals are sent to the electronic controller 194, which determines the pilot fuel pressure at that location.

[0052] The pressure regulator 144 is employed to maintain a pressure differential between the pilot fuel pressure in the pilot fuel rail 280 and the gas fuel pressure in the gas fuel rail 170 within a desired range (where the pilot fuel pressure is greater than the gas fuel pressure by at least a desired margin) so that the pilot fuel can be employed as a hydraulic fluid in the actuation of the dual fuel injector 184 and used to form a liquid seal to seal the gas fuel within the dual fuel injector 184. The pressure differential is also referred to as a system bias. Applicant's U.S. Patent No. 6,298,833, issued on October 9, 2001, discloses various embodiments of an exemplary pressure regulator 144 that may be employed herein, but other techniques may also be employed to maintain a bias between the two fuels. These techniques are generally referred to as gas follows diesel (GFD) and diesel follows gas (DFG), where the first listed fuel refers to the fuel whose pressure is regulated according to the pressure of the second listed fuel. The pressure sensor 310 generates signals indicative of the pilot fuel pressure in the pilot fuel rail 280 downstream of the pressure regulator 144, and these signals are sent to the electronic controller 194 so that the electronic controller can determine the pilot fuel pressure at that location. The pressure regulator 144 can mechanically regulate one fuel pressure based on the other fuel pressure. In other embodiments, a separate electronically controlled gaseous fuel pressure regulator can regulate the gaseous fuel pressure independently but in relation to the pilot fuel rail pressure, in which case the electronically controlled gaseous fuel pressure regulator is operably connected to and controlled by the controller 194. The dual fuel injector 184 is fluidly connected to the pilot fuel rail 280 and the gaseous fuel rail 170, and the dual fuel injector 184 is operable to separately and independently inject the pilot fuel and the gaseous fuel into the combustion chamber 114 through the nozzle 290 at which the nozzle 290 of the dual fuel injector 184 is disposed. In other embodiments, where the pilot fuel is another type of gaseous fuel, a separate hydraulic fluid may perform the actuation and sealing functions that would otherwise be performed by the liquid pilot fuel. In addition to dual fuel injectors, separate gaseous fuel injectors and pilot fuel injectors are also contemplated in engine systems where space permits separate injection of gaseous fuel and pilot fuel, respectively. The electronic controller 194 is operably connected to the pumping device 260 and the fuel injectors 184 to command operation of the pumping device 260 and the fuel injectors 184. The pressure of the pilot fuel in the pilot fuel rail 280 is also referred to as the pilot fuel injection pressure, and as disclosed in the previous embodiments, the pressure of the gaseous fuel in the gaseous fuel rail 170 is referred to as the gaseous fuel injection pressure (which is essentially the delivery pressure of the gaseous fuel delivered to the injectors 184).

[0053] In other embodiments, two or more storage containers may be used, wherein each storage container stores one type of gaseous fuel. Figure 5 , the storage container 131 stores the first gas fuel as compressed gas and the storage container 132 also stores the second gas fuel as compressed gas, and these storage containers can replace the storage container 130 and be respectively used in Figure 1 , Figure 2 , Figure 3 and Figure 4 In the fuel system 101, the fuel system 102, the fuel system 103 and the fuel system 104. Figure 5 The electronic controller 19x in the figure indicates Figure 1 , Figure 2 , Figure 3 and Figure 4 The electronic controller 19x commands one of the shut-off valves 340 and 350 to open to allow the first gas fuel and the second gas fuel to flow from the storage container 131 and the storage container 132 to the conduit 174, respectively. The pressure sensors 201 and 202 generate signals representing the gas fuel supply pressures in the storage containers 131 and 132, respectively. In some embodiments, the electronic controller 19x, for example based on the set position arrangement of the first storage container 131 and the second storage container 132, inherently knows whether the internal combustion engines 121, 122, and 124 are supplied with the first gas fuel or the second gas fuel. In other embodiments, the electronic controller can receive an analog signal or a digital signal indicating which storage container contains the first gas fuel and which storage container contains the second gas fuel.

[0054] Reference Figure 6 As an alternative to storing the first gas fuel as a compressed gas, the storage container 131b stores the first gas fuel in a liquefied form. Depending on the container and the gas fuel, the liquefied gas fuel can be stored at ambient temperature to very low temperatures (including low temperatures <130K) and at low pressure (at atmospheric pressure or close to atmospheric pressure) to high pressure (>200bar). In order to store at low temperatures, the container generally has an inner container (134) and an outer container (138), the inner container (134) being used to hold the cryogenic fluid, and an insulating space between the inner container (134) and the outer container (138), the insulating space extending the holding time. When the inner container 134 is reinforced for holding a higher pressure fluid, such as when the inner container 134 is a cryogenic compression container device, the fluid can be stored at low temperatures and high pressures ( Gundam500bar). As an example of a gas fuel stored in a liquefied form at low temperature and low pressure, the first gas fuel in the storage container 131b can be natural gas stored in a liquefied form at a temperature of about 112K and at 1 atmosphere or close to 1 atmosphere. When the liquefied gas fuel is stored at ambient pressure or close to ambient pressure, a cryogenic pump 225 can be used to pressurize the first gas fuel, and a vaporizer 235 changes the state of the pressurized fuel from a liquid state to a gaseous state or a supercritical state (depending on the temperature and pressure of the vaporized gas fuel). Although the cryogenic pump 225 and the vaporizer 235 are illustrated outside the storage container 131b, in other embodiments, the cryogenic pump 225 and the vaporizer 235 can be at least partially disposed within the storage container 131b. Since gas fuel in a liquid state is easier to compress than gas fuel in a gaseous state, less energy is required for compression, and thus in this specific example, the first gas fuel does not need to be compressed by compressor 220, but is only pressurized by cryogenic pump 225, so that the downstream side of shut-off valve 340 can be directly fluidly connected to delivery conduit 172 (i.e., downstream of compressor 220) rather than conduit 174 (i.e., upstream of compressor 220).

[0055] The storage containers disclosed herein may be a single storage container that is fueled with a first gaseous fuel and subsequently fueled with a second gaseous fuel that differs from the first gaseous fuel in at least the mole % content of hydrogen contained therein. Where more than one storage container is employed, each container may be designated for a type of gaseous fuel, i.e., the first storage container stores the first gaseous fuel and the second storage container stores the second gaseous fuel that differs in at least the mole % content of hydrogen contained therein; or the determination of the type of fuel stored in each container may be set and / or otherwise input to a controller, such as when the storage container is filled or ascertained onboard during an engine fueling operation. The mole % of hydrogen in the fuel is equal to the volume % of hydrogen in the fuel when at standard pressure and temperature. A separate container for storing a first gas fuel and a separate container for storing a different second gas fuel can be arranged independently of one another, or in an integrated manner, for example, an outer container encasing two inner storage containers as described in co-owned U.S. Patent No. 7,850,034, which discloses a multi-fuel storage device in which the two gas fuels are stored in separate insulated spaces within a single outer container shield, thereby further isolating the two gas fuels therein and increasing the storage density of the two gas fuels. Depending on the storage container used, the gas fuels can also be stored in a liquefied form, a compressed form, and / or a cryogenically compressed form. Figure 6Like the storage container 131b in, the gaseous fuel is stored at ambient temperature to very low temperature (including low temperature <130K) and at a pressure range from low pressure (close to atmospheric pressure) to high pressure (>200bar) depending on the container specifications and the gaseous fuel.

[0056] Reference Figure 7a , Figure 7b , Figure 7c and Figure 7d As an example of a gaseous fuel stored at very low temperatures and high pressures, hydrogen may be stored in cryogenically compressed form and nominally pressurized to a pressure of 250-350 bar, although such containers are capable of storing hydrogen (and other gaseous fuels) at temperatures ranging from cryogenic to ambient temperature and at pressures ranging up to 500 bar. Figure 7a Optionally, a cryogenic pump 225 may be employed to raise the pressure of the gaseous fluid leaving the storage container 130c to a higher pressure; however, in other embodiments, the gaseous fuel leaving the storage container 130c flows directly to the vaporizer 235, which increases the enthalpy of the pressurized fuel, and depending on the supply pressure of the gaseous fuel as indicated by the pressure sensor 203, the gaseous fuel may be supplied directly to the delivery conduit 172 ( Figure 7a and Figure 7d ) and supplied to the gaseous fuel rail 170 through the supply conduit 173. Note that when both the supply conduit 173 and the supply conduit 174 are present, the shut-off valve 350 and the shut-off valve 355 may be employed such that: the controller 19x commands the valve 355 to be in an open position, thereby allowing fluid to flow from the supply conduit 173 through the valve 355 to the delivery conduit 172, and the controller 19x commands the shut-off valve 350 to be in a closed position, thereby blocking fluid from flowing through the supply conduit 174 to the delivery conduit 172. Alternatively, or in addition to employing the pump 225, the pressure of the gaseous fuel leaving the storage container 130c may be controlled using the vaporizer 235 (and Figure 7c The pressure of the gaseous fuel is increased by directing the fluid through the supply conduit 174 to the compressor 220. In embodiments where the compressor 220 is used instead of or in addition to the cryogenic pump 225 to increase the pressure of the gaseous fuel, the pressure sensor 203 generates a pressure representative of the vaporizer 235 (and the vaporizer 237) upstream of the compressor 220. Figure 7cand when the gas supply pressure is greater than or equal to the desired injection pressure, the compressor 220 does not need to pressurize the gas fuel from the storage container 130c, and the controller 19x selectively commands the bypass valve 230 to be in the bypass position to fluidly pass the gas fuel from the storage container around the compressor 220; and when the gas fuel supply pressure upstream of the compressor 220 is less than the desired injection pressure, the bypass valve 230 is selectively commanded to be in the blocking position to fluidly pass the gas fuel from the storage container 130c (and the vaporizers 235, 237) through the compressor 220. Similarly, when both the supply conduit 173 and the supply conduit 174 are present, the shut-off valve 350 and the shut-off valve 355 can be used, and the controller 19x commands the shut-off valve 350 to be in the open position, thereby allowing fluid to flow through the shut-off valve 350 into the supply conduit 174, and the controller 19x commands the shut-off valve 355 to be in the closed position, thereby blocking the fluid from flowing through the supply conduit 173 to the delivery conduit 172. Instead of using shut-off valves 350 and 355 , a switching device such as a three-way valve may be used upstream of compressor 220 to selectively control gas fuel flowing from storage container 130 c through supply conduit 173 and / or supply conduit 174 and to delivery conduit 172 and gas fuel rail 170 .

[0057] In some embodiments, a single storage container may be used to store the first gas fuel and the second gas fuel and selectively supply each of the first gas fuel and the second gas fuel to the fuel tank. Figure 1 , Figure 2 , Figure 3 and Figure 4 The first gas fuel and the second gas fuel are supplied to the engines 121, 122, and 124 in the fuel systems 101, 102, 103, and 104 shown in FIG. 1 . In the exemplary embodiment, and with particular reference to FIG. Figure 7b , Figure 7c and Figure 7d, the storage container 130c can store the first gas fuel, the second gas fuel, or both gas fuels in a single storage container, and the storage container 130c can selectively and independently supply the two gas fuels to the delivery conduit 172 through separate conduits (conduit 176 and conduit 178), which are both fluidly connected to the storage container 130c. For example, a cryogenic compression storage container can contain the first gas fuel and the second gas fuel at a pressure and temperature at which the first gas fuel is in a liquid state and the second gas fuel is in a gaseous state. An outer container as described in co-owned U.S. Patent No. 7,850,034 encases two inner storage containers, which discloses a multi-fuel storage device, wherein the two gas fuels are stored in separate insulated spaces within a single outer container shield, thereby further isolating the two gas fuels therein and increasing the storage density of the two gas fuels. In another exemplary embodiment, the storage container 130c may store liquefied natural gas as a first gas fuel in the lower portion 135 of the storage container 130c, and a mixture of natural gas and hydrogen as a second gas fuel in the form of vapor in the upper portion 136 of the storage container 130c. Depending on the pressure and temperature in the container 130c, the mole % of natural gas and the mole % of hydrogen in the vapor mixture will change when the two fuels are stored together in the same space in the container 130c; that is, the two gas fuels are stored in the same space, rather than being separated by, for example, multiple internal containers or storage containers with a selectively permeable structure, such as a membrane, which allows hydrogen to pass through the membrane into the isolated space in the storage container, but does not allow larger hydrocarbons such as methane to pass through. Hydrogen has a much lower specific density than natural gas (mainly methane), and hydrogen liquefies at a much lower temperature and at a higher pressure than natural gas, and hydrogen can be stored in the form of vapor in the same container that stores natural gas in liquefied form.

[0058] In an exemplary embodiment in which a first gas fuel and a second gas fuel are stored simultaneously in the same storage space of a storage container, the first gas fuel in the form of a liquefied gas fuel (such as liquefied natural gas) is supplied to the vaporizer 235 from the lower portion 135 of the storage container 130c through the conduit 178. An optional cryogenic pump 225 may be used to pressurize the first gas fuel before the vaporizer 235 changes the state of the pressurized fuel from a liquid state to a gaseous state or a supercritical state (depending on the temperature and pressure of the vaporized gas fuel). Alternatively, or in addition to using the pump 225, a compressor downstream of the vaporizer 235 may be used to increase the pressure of the first gas fuel. The second gas fuel in the form of vapor is supplied from the upper portion 136 of the storage container 130c through the conduit 176. The pressure sensor 202 generates a signal representing the storage pressure 130c. When the engine is fueled with gas fuel supplied from the storage container 130c through the conduit 176, the shut-off valve 350 and the shut-off valve 345 ( Figure 7d 20 ) is in an open flow position to allow the second gas fuel to flow from conduit 176 to conduit 174 upstream of compressor 220. Note that check valve 215 is a one-way valve on conduit 178 that allows fluid to flow out of storage container 130c through liquefied gas fuel conduit 178, but does not allow fluid to flow back into storage container 130c from conduit 178 in the opposite direction. A check valve or valve such as shut-off valve 340 ( Figure 7b and Figure 7c ) or three-way valve 325 ( Figure 7d ) to similarly block the flow of fluid from conduit 176 and conduit 174 through vaporizer 235 to liquefied gas fuel conduit 178. Figure 7b and Figure 7c As best seen in FIG. 1 , when fueling the engine with gaseous fuel supplied from storage container 130c through conduit 178, shut-off valve 350 may be commanded to a closed position and shut-off valve 340 may be commanded to an open position (and shut-off valve 345, if present, to an open position) to allow gaseous fuel to flow from conduit 178 to supply conduit 174 upstream of compressor 220. In the case of a three-way valve such as three-way valve 325 ( Figure 7d), the three-way valve is commanded to be in a flow position to allow gas fuel to flow from liquefied gas fuel conduit 178 through vaporizer 235 (and optional pump 225) to supply conduit 174, and to block gas fuel from conduit 178 (and conduit 174) to conduit 176. Where a shut-off valve 350 is present, the shut-off valve 350 may also be commanded to be in a closed position to block fuel from conduit 178 to conduit 176. The pressure sensor 203 and / or the sensor 202 generate a signal representing the supply pressure in the supply conduit 174 upstream of the compressor 220, and when the first gas supply pressure is greater than or equal to the desired injection pressure of the first gas fuel or when the second gas supply pressure is greater than or equal to the desired injection pressure of the second gas fuel, the compressor 220 does not need to pressurize the gas fuel, and the bypass valve 230 is selectively commanded by the controller to be in a bypass position to fluidly transfer the first gas fuel or the second gas fuel from the storage container 130c from around the compressor 220 to the delivery conduit 172; and when the first gas fuel pressure is less than the desired injection pressure of the first gas fuel or when the second gas fuel pressure is less than the desired injection pressure of the second gas fuel, the bypass valve 230 is selectively commanded to be in a blocking position to fluidly transfer the first gas fuel or the second gas fuel from the container 130c through the compressor 220 to further pressurize the gas fuel.

[0059] It is worth noting that in Figure 7b In the embodiment, the gas fuel supplied from the vapor space of the upper portion 136 of the storage container 130c is fluidly connected to the conduit 174 downstream of the vaporizer 235 and upstream of the compressor 220. Alternatively, as Figure 7c As shown, the gaseous fuel supplied from the vapor space of the upper portion 136 of the storage vessel 130c may first fluidly flow through a vaporizer 237 which increases the enthalpy of the pressurized gaseous fuel to a desired fuel temperature for fueling the internal combustion engine. Figure 7c In FIG. 2 , vaporizer 237 integrates a first vaporizer (such as vaporizer 235 ) and a second vaporizer in a single housing; however, alternatively, two separately housed vaporizers may be employed depending on, for example, space and other system limitations.

[0060] In embodiments where compressor 220 is used with both the first gas fuel and the second gas fuel, optional switchgear 325 (in Figure 7dThe switch device 325 (shown as a three-way valve 325) fluidly connects the outlet of the vaporizer 235 (or the two gas fuel outlets of the vaporizer 237) with the conduit 174 upstream of the compressor 220. The switch device 325 can be a manual valve, or the controller 19x can command the switch device 325 to be in a position that allows fluid to flow from the vaporizer 235 to the conduit 174 upstream of the compressor 220. The pressure sensor 203 generates a signal representing the supply pressure leaving the vaporizer 235 (and the vaporizer 237), and when the gas pressure is greater than or equal to the desired injection pressure, the compressor 220 does not need to pressurize the gas fuel, and the controller selectively commands the bypass valve 230 to be in the bypass position to fluidly transfer the gas fuel from the vaporizer 235 from around the compressor 220 to the delivery conduit 172; and when the pressure of the gas fuel leaving the vaporizer 235 is less than the desired injection pressure, the bypass valve 230 is selectively commanded to be in the blocking position to fluidly transfer the gas fuel from the vaporizer 235 through the compressor 220 to further pressurize the first gas fuel.

[0061] and Figure 5 similar, Figure 6 , Figure 7a , Figure 7b , Figure 7c and Figure 7d The electronic controller 19x in the figure indicates Figure 1 , Figure 2 , Figure 3 and Figure 4 The electronic controller 19x commands one of the corresponding electronic controllers 191, 192, 193, and 194 in the embodiment of the present invention. The electronic controller 19x commands one or more of the shut-off valves 340, 345, 350, and 355 to open to allow the gaseous fuel to flow from the corresponding containers 130c, 131b, and 132 to the conduit 172. The pressure sensor 203 generates a signal representing the supply pressure of the gaseous fuel in the supply conduits 173 and 174 downstream of the vaporizer 235, while the pressure sensor 202 generates a signal representing the storage pressure of the gaseous fuel in the storage container 132, which may also be the storage pressure of the compressor 220 ( Figure 5 ) upstream of the supply pressure. Pressure sensor 203 generates a pressure signal indicating the supply pressure of carburetor 235 ( Figure 7a ) and the signal of the supply pressure of the gas fuel in the supply conduit 173 downstream of the vaporizer 235 and the vaporizer 237 ( Figure 7b , Figure 7c , Figure 7d ) is a signal of the supply pressure of the gaseous fuel in the supply conduit 174 downstream of the gaseous fuel supply conduit 174.

[0062] Return to reference Figure 1 , Figure 2 , Figure 3 and Figure 4 , the signal 320x in the fuel system 101, 102, 103, and 104 indicates the type of gaseous fuel currently being supplied to the internal combustion engines 121, 122, and 124. The signal 320x is received by the electronic controller 191, 192, 193, and 194, and the signal 320x may be a digital signal or an analog signal. Figure 8a In one embodiment, signal 320x may be signal 320a generated by a fuel type switch 330 that is operated by a user in a first position (represented as a logic 0) or a second position (represented as a logic 1), wherein the first position represents a first gas fuel and the second position represents a second gas fuel. In other embodiments, there may be more than one digital signal 320a so that more than two types of gas fuels may be selected, wherein the switch may be, for example, a rotary switch having three or more positions. Instead of using a fuel type switch 330, a user may input or select the type of gas fuel through a user interface (not shown) of electronic controllers 191, 192, 193, and 194. In embodiments where multiple signals indicating the type of the first gas fuel and / or the second gas fuel are received by electronic controllers 191, 192, 193, and 194, the electronic controllers may employ advanced signal control to provide signal priority or signal preemption.

[0063] Reference Figure 8b In another embodiment, signal 320x may be signal 320b generated by hot wire sensor 360 that is affixed to inner surface 370 of gas fuel rail 170. Instead of gas fuel rail 170, hot wire sensor 360 may be affixed within conduit 174 or conduit 172, and hot wire sensor 360 is typically affixed in any conduit between storage vessels 130, 130c, 131, 131b, and 132 and injectors 180 and 184. The gaseous fuel flowing through the hot wire sensor cools the sensor, and the amount of cooling varies with the type of gaseous fuel for a given engine load and engine speed condition. Signal 320b indicates the type of gaseous fuel flowing through hot wire sensor 360, and signal 320b varies with the temperature of the hot wire sensor, which in turn varies with the mass flow rate of the specific type of gaseous fuel flowing through the hot wire sensor. In an embodiment using the hot wire sensor 360, the signal 320b may be an analog signal or a digital signal indicating the temperature of the hot wire sensor 360 or the temperature change across the hot wire sensor 360. In other embodiments, the hot wire sensor 360 may process the temperature signal itself to determine the type of the gaseous fuel, and the hot wire sensor 360 may transmit information indicating the type of the gaseous fuel to the electronic controller 19x via an analog signal or a digital signal.

[0064] Alternatively or additionally, in other embodiments, a combustion sensor as disclosed in the applicant's U.S. Patent No. 10,519,888 issued on December 31, 2019 may be used in fuel system 101, fuel system 102, fuel system 103, and fuel system 104. The combustion sensor uses an accelerometer sensor (which may be a knock sensor) and an intake manifold pressure sensor, which is a type of acoustic sensor that generates a first pressure signal representing the combustion chamber pressure, and the intake manifold pressure sensor generates a second pressure signal representing the intake manifold pressure. The first pressure signal and the second pressure signal together represent signal 320x (see Figure 1 , Figure 2 , Figure 3 and Figure 4 ), and the first pressure signal and the second pressure signal are received and processed by electronic controllers 191, 192, 193, and 194 to determine the type of gaseous fuel currently consumed by engines 121, 122, and 124. The combustion sensor can detect a change in fuel quality, which can be the result of a change in the type of fuel supplied to engines 121, 122, and 124 (including a change in composition), such as by mixing different types of fuel in storage container 130, storage container 130c, storage container 131, storage container 131b, and / or storage container 132.

[0065] Reference Fig. 9, a flow chart of an algorithm 400 is shown for regulating gaseous fuel pressure and injecting gaseous fuel into corresponding combustion chambers 111, 112, and 114 in internal combustion engines 121, 122, and 124. Algorithm 400 is programmed into electronic controllers 191, 192, 193, and 194. In step 410, engines 121, 122, and 124 are started, and in step 420, electronic controllers 191, 192, 193, and 194 determine whether to fuel internal combustion engines 121, 122, and 124 with a first gaseous fuel or a second gaseous fuel. The electronic controllers 191, 192, 193, 194 may determine the type of gaseous fuel being used by employing one or more onboard sensors that provide one or more signals indicative of the fuel type and / or provide one or more remote signals or wireless signals that indicate the type of gaseous fuel stored in the storage container supplying the internal combustion engine or in each storage container supplying the internal combustion engine. Depending on system requirements, such as the resolution of the compositional accuracy of the mole percentage of hydrogen in the gaseous fuel, one or more fuel type indicators may be employed, including a fuel type switch 330, a hot wire sensor 360, a combustion sensor, a capacitive sensor, a dynamic viscosity sensor, a discrete acoustic wave and phase detection sensor, spectral analysis data (e.g., spectral analysis data from near infrared or fiber enhanced Raman spectroscopy), or any other known or future developed technology. When the first gaseous fuel is stored in a storage container different from the storage container storing the second gas storage container, such as in Figure 5 and Figure 6In the illustrated embodiment, the electronic controllers 191, 192, 193, and 194 can then non-inherently know which fuel type is currently flowing to the engines 121, 122, and 124 by selecting which of the shut-off valves 340 and 350 (controlled by the electronic controllers) is open. In the event that the first gaseous fuel is currently flowing to and being consumed by the engines 121, 122, and 124, in step 430, the electronic controllers 191, 192, 193, and 194 command a first injection pressure, and in step 440, the electronic controllers 191, 192, 193, and 194 command an injection amount of the first gaseous fuel to be injected into the respective combustion chambers of the engines 121, 122, and 124. In the case where the second gaseous fuel is currently flowing to the engines 121, 122, and 124 and being consumed by the engines 121, 122, and 124, in step 450, the electronic controllers 191, 192, 193, and 194 command the second injection pressure, and in step 460, the electronic controllers 191, 192, 193, and 194 command the injection amount of the second gaseous fuel injected into the corresponding combustion chambers of the engines 121, 122, and 124. Whether the injection amount of the first gaseous fuel or the injection amount of the second gaseous fuel is injected, the gaseous fuel is injected late in the compression stroke, and in particular, the gaseous fuel is injected within 90 crank angle degrees (CA°) of the top dead center (TDC) during the compression stroke, and more particularly, the gaseous fuel is injected within 45 CA° of TDC during the compression stroke, so that the injection amount of the first gaseous fuel or the injection amount of the second gaseous fuel is burned in a diffusion combustion mode. In an exemplary embodiment, the first gaseous fuel is natural gas, and the second gaseous fuel is hydrogen. When the first gaseous fuel and the second gaseous fuel are defined in this way, the second injection pressure is a pressure value less than the first injection pressure. The comparison of the first injection pressure and the second injection pressure is carried out under the same engine load and engine speed conditions. In this regard, the first injection pressure can vary with the engine load and engine speed conditions, and the second injection pressure can vary with the engine load and engine speed conditions. The pressure value between the first injection pressure and the second injection pressure can be greater than 15bar in some embodiments, greater than 20bar in other embodiments, and greater than 25bar in yet other embodiments, and the pressure value between the first injection pressure and the second injection pressure varies with fuel composition and / or engine operation requirements. Referring back to step 410, in step 410, engines 121, 122, and 124 are started, and it is worth noting that the injection pressure during the start-up can be the first injection pressure, the second injection pressure, or another injection pressure suitable for the start-up of the engine.In other embodiments, the algorithm 400 is not limited to only two types of gaseous fuels, and the algorithm 400 can distinguish between more than two types of gaseous fuels. For example, the two or more types of gaseous fuels can be natural gas, hydrogen, and mixtures of natural gas and hydrogen with different mixing ratios. In a practical example, when only one storage container is used and filled with natural gas and / or hydrogen, different mixtures can exist in the storage container. In another example, when only one storage container is used and stores natural gas in liquefied form and a mixture of hydrogen and natural gas in vapor form, different mixtures of natural gas and hydrogen can be supplied through conduit 176, and natural gas can be supplied through liquefied gas fuel conduit 178.

[0066] Fuel systems 101, 102, 103, 104 may be employed in applications using only hydrogen as a fuel, so that signal 320x (see Figure 1 , Figure 2 , Figure 3 ,and Figure 4 ), whereby the electronic controllers 191, 192, 193, and 194 are programmed that the gaseous fuel in the storage containers 130, 130c, 131, 132 is only hydrogen. In the context of the present application, the reference fuel gas is essentially a reference to a specific gas. For example, as a fuel gas for a refueling station, the purity of the gaseous fuel is subject to geographical regulations and must generally meet or exceed a specified purity specification. One such specification for hydrogen as a fuel gas is the international standard ISO 14687-2-2019, which specifies the maximum allowable concentrations of a number of key impurities depending on the use, and which has been adopted by many jurisdictions. The electronic controllers 191, 192, 193, and 194 know a priori that the fuel is hydrogen, making it unnecessary to detect the type of gaseous fuel. Now referring to Fig.10, a flow chart of an algorithm 500 is shown for regulating the gaseous fuel pressure and injecting the gaseous fuel into the corresponding combustion chambers 111, 112, and 114 in the internal combustion engines 121, 122, and 124 when the gaseous fuel is hydrogen. In step 510, the engines 121, 122, and 124 are started. In step 520, the electronic controllers 191, 192, 193, and 194 command the injection pressure of the gaseous fuel (i.e., hydrogen), which injection pressure may vary with engine load and engine speed conditions. In an exemplary embodiment, when the engines 121, 122, and 124 are operated at a power level greater than 50% of their maximum output power, the injection pressure employed may be equal to a multiplication factor multiplied by the in-cylinder peak pressure in at least a portion of the engine output power range. The in-cylinder peak pressure is the peak pressure in the combustion chamber produced by combustion. In some exemplary embodiments, the multiplication factor is in the range of 1.15 to 1.40, and in other exemplary embodiments, the multiplication factor is in the range of 1.16 to 1.3, and in yet other exemplary embodiments, the multiplication factor is in the range of 1.17 to 1.25. As an example, when the in-cylinder peak pressure is 210 bar, in some embodiments, the injection pressure can be in the range of 241.5 bar to 294 bar, and in other embodiments, the injection pressure can be in the range of 243.6 bar to 273 bar, and in yet other embodiments, the injection pressure can be in the range of 245.7 bar to 262.5 bar. An exemplary multiplication factor of 1.2 for hydrogen provides a good balance between efficiency and NOx emissions. In contrast, for other gaseous fuels such as natural gas, an exemplary multiplication factor of about 1.43 provides a similar relative balance between efficiency and NOx emissions, such that when the in-cylinder peak pressure is 210 bar, the selected injection pressure is about 300 bar. In step 530 , electronic controllers 191 , 192 , 193 , and 194 command the in-cylinder fuel injectors to inject an injection amount of gaseous fuel into the combustion chamber within 90 crank angle degrees of top dead center during the compression stroke.

[0067] For various reasons, it is counterintuitive to reduce the injection pressure when adding fuel with hydrogen and burning the fuel in a diffusion combustion mode compared to other gaseous fuels. For example, one reason is that the energy content of the hydrogen (second fuel) injected into the combustion chamber is less than the energy content of the first fuel when injected at the same injection pressure and the same injection volume is injected. According to Equation 1 below, the energy content per unit volume of fuel that can be released as heat during combustion is proportional to the product of the calorific value of the fuel and the density of the fuel. As an example, Table 1 below lists the lower heating value, density, energy content per unit volume, and energy ratio when the first gas fuel is natural gas and the second gas fuel is hydrogen. According to Table 1, when the same volume is injected at the same injection pressure, the energy content of the injected natural gas is 3.06 to 3.93 times the energy content of the injected hydrogen. Based on this analysis, it is expected that the injection pressure must be increased when injecting hydrogen compared to injecting natural gas. Alternatively or additionally, the injection window of hydrogen may also be increased; however, when the fuel is introduced late during the compression stroke so that the fuel burns in a diffusion combustion mode, there may not be sufficient time to introduce the fuel by widening the injection window.

[0068] Energy content ∝ calorific value * density Equation 1

[0069]

[0070] 1) Close to lower calorific value,

[0071] https: / / www.engineeringtoolbox.com / fuels-higher-calorific-values-d_ 169.html

[0072] 2) Density at standard temperature and pressure, which are defined as 0°C and 1 atm.

[0073] Table 1

[0074] Furthermore, as a rule consistent with most fuels, lower injection pressures do not improve combustion because the turbulence created during injection is reduced, which reduces local mixing of fuel with air, which reduces ignition and combustibility due to increased local rich air / fuel equivalence ratio regions. The air / fuel equivalence ratio, also known as lambda, is defined as the ratio of the air / fuel ratio to the stoichiometric air / fuel ratio, where lambda=1 when the air / fuel equivalence ratio is stoichiometric, lambda>1 when the air / fuel equivalence ratio is high air fraction (lean), and lambda<1 when the air / fuel equivalence ratio is high fuel fraction (rich). Note that when the overall or global air / fuel equivalence ratio in the combustion chamber is stoichiometric (λ=1) or high air fraction (λ>1), there may still be regions of air / fuel equivalence ratio (λ<1) with local high fuel fractions in the combustion chamber due to lack of mixing of fuel with air prior to ignition and combustion. For typical gaseous fuels, it is desirable to reduce, and in some cases eliminate, localized areas of high fuel concentration prior to ignition and combustion.

[0075] Now refer to Fig.11 , graph 600 illustrates the relationship between adiabatic flame temperature (on the y-axis) and fuel / air equivalence ratio (on the x-axis), and graph 600 includes a curve 610 for methane (CH4) and a curve 620 for hydrogen (H2). The fuel / air equivalence ratio, also known as (phi), is the inverse of the air / fuel equivalence ratio (λ), where, for a stoichiometric fuel / air mixture, λ = 1, for a fuel / air mixture with a high air content, λ>1, and for a fuel / air mixture with a high fuel fraction, λ<1. On the high fuel ratio side The adiabatic flame temperature of natural gas decreases faster than that of hydrogen. This is probably due to the fact that several reaction mechanisms such as steam methane reforming and pyrolysis are strongly endothermic. Fig.12 , graph 700 illustrates the relationship between laminar flame speed (on the y-axis) and fuel / air equivalence ratio (on the x-axis), and graph 700 includes a curve 710 for methane (CH4) and a curve 720 for hydrogen (H2). The peak laminar flame speed 740 of hydrogen is more than six times the peak laminar flame speed 730 of methane. When the peak laminar flame speed 730 of methane is approximately stoichiometric, the flame speed of the fuel / air equivalence ratio is 1.0. When the hydrogen gas has a peak laminar flame speed of 740, it appears clearly on the high fuel ratio side. The adiabatic flame temperature and laminar flame speed of hydrogen indicate that hydrogen is more tolerant of high fuel fraction operation than methane (and natural gas, since natural gas typically contains about 95 mol% methane with methane content ranging from 87 mol% to 98 mol%). Therefore, injecting hydrogen at a reduced injection pressure compared to the injection pressure used to inject natural gas (and all other gaseous fuels) does not reduce engine efficiency, and in fact, efficiency and fuel economy may improve because there are more localized high fuel fraction areas when hydrogen is injected at lower injection pressures.

[0076] In addition, the greater diffusivity of hydrogen compared to other gaseous fuels such as natural gas is also a factor in why the efficiency of engines 121, 122, and 124 remains within acceptable ranges when the injection pressure of hydrogen is reduced compared to other gaseous fuels under given engine load and engine speed conditions, and the injection pressures are particularly but not limited to those injection pressures employed when the engines are operated above 50% of their maximum rated output power. In contrast, where these other gaseous fuels are injected at reduced injection pressures, the efficiency of engines 121, 122, and 124 will decrease below acceptable values. For example, hydrogen is more diffusive in air than natural gas. The mass diffusion coefficient of hydrogen in excess air at 1 atmosphere and 20°C is about 0.756 cm 2 / s. Natural gas is a mixture of gaseous fuels, the main component of which is methane (usually natural gas contains about 95 mol% methane, with the methane content ranging from 87 mol% to 98 mol%). The mass diffusion coefficient of methane in excess air at 1 atmosphere and 20°C is 0.21 cm 2 / s. The ratio of the mass diffusion coefficient of hydrogen to the mass diffusion coefficient of methane is 3.6 (0.756 / 0.21). Compared to natural gas (and other gaseous fuels), the greater mass diffusion coefficient of hydrogen allows hydrogen to mix more efficiently with air in the combustion chambers 111, 112, 114 when hydrogen is injected at a reduced injection pressure.

[0077] By reducing the injection pressure of hydrogen when fueling with hydrogen as compared to natural gas, the fuel economy of engines 121, 122, and 124 can be improved. Fig.13 and Fig.14 , showing a graph 800 of storage pressure and a graph 900 of injection pressure. Storage pressure curve 810 represents the storage pressure of hydrogen when the hydrogen is stored as a compressed gas in a storage container, such as: Figure 1 , Figure 2 , Figure 3 and Figure 4 A storage container 130; Figure 5 and Figure 6 Storage container 131 and storage container 132; or Figures 7a to 7d As engines 121, 122, and 124 consume hydrogen from these storage containers, the storage pressure and therefore the supply pressure increases from the maximum storage pressure P SMAX Reduce to minimum storage pressure P SMIN , maximum storage pressure P SMAX is the maximum rated pressure that can be stored in the storage container, the minimum storage pressure P SMIN is the minimum pressure required for engine operation. Storage pressure curve 810 is illustrated as a linear decreasing function; however, this is not a requirement and more generally, the storage pressure curve decreases as a monotonically non-increasing function during operation between refueling of the storage container. Injection pressure curve 910 represents the injection pressure of hydrogen in gaseous fuel rail 170, which is substantially equal to the delivery pressure to the fuel injector. Segment 920 of injection pressure curve 910 represents the dynamic injection pressure P DINJ A region 930 of operation is shown in which the injection pressure tracks and is substantially equal to the storage pressure. Due to pressure drops across valves and other components in the fuel systems 101, 102, 103, and 104, a small difference between the storage pressure and the injection pressure may exist in the dynamic region 930. Segment 940 of the injection pressure curve 910 represents the static injection pressure P SINJ Region 950 of operation, in which the storage pressure has dropped below the desired injection pressure, such that the supply pressure needs to be increased (e.g., by Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7a , Figure 7b , Figure 7c and Figure 7d The compressor 220 in the injection nozzle increases the static injection pressure P SINJ (i.e., desired injection pressure). Note that there may be more than one desired injection pressure depending on engine load and engine speed, whereby the injection pressure operation switches back and forth between dynamic region 930 and static region 950 as engine load and engine speed change. By lowering the static injection pressure P of hydrogen compared to other gaseous fuels such as natural gas, the desired injection pressure P of hydrogen may be increased. SINJ(i.e., the desired injection pressure), the storage pressure is allowed to decrease to a lower value before the compressor 220 needs to be turned on to compress the hydrogen to the desired injection pressure. Therefore, in the case where the desired injection pressure is reduced, the compressor 220 is operated less, thereby reducing the parasitic power consumption caused by operating the compressor 220, thereby improving the fuel economy of the engines 121, 122, and 124. In addition, within the region 930 of dynamic injection pressure operation, by sending the higher storage pressure directly to the injector, the combustion efficiency of the engines 121, 122, and 124 can be improved, because generally higher injection pressures lead to higher efficiency, especially in the case where the engine does not need to expend energy to compress the gaseous fuel to a higher injection pressure, the combustion efficiency of the engines 121, 122, and 124 can be improved; that is, the advantage is that there is no energy consumption in the dynamic region 930. Note that when the storage pressure is initially higher than the desired injection pressure, the technology is also applicable to engines 121, 122, and 124 operating with any gaseous fuel.

[0078] Now refer to Fig.15 , illustrates an algorithm 1000 for regulating the gaseous fuel pressure and injecting the gaseous fuel into the respective combustion chambers 111, 112, and 114 of the internal combustion engines 121, 122, and 124. The algorithm 1000 is programmed into the electronic controllers 191, 192, 193, and 194, and when the algorithm 1000 is executed by the electronic controllers, the entry point into the algorithm is step 1010. In step 1020, the electronic controllers 191, 192, 193, and 194 determine the supply pressure P S , the supply pressure P S represents the pressure in the storage container 130 (see Figure 1 , Figure 2 , Figure 3 and Figure 4 ); or the supply pressure P S Indicates the pressure in the storage container 131 or the storage container 132 (see Figure 5 and Figure 6 ); or when conduit 176 is opened to supply supply conduit 174 upstream of compressor 220 (see Figure 7b and Figure 7d ), the supply pressure P S represents the pressure in the storage container 130c. Supply pressure P S It can also represent the pressure of the gas fuel supplied from the storage container 130c in the storage container supply conduit 173 and the supply conduit 174 after the gas fuel has left the vaporizer 235 or the vaporizer 237 upstream of the compressor 220. In step 1030, the desired injection pressure P DesInjThe desired injection pressure is determined to vary with engine load and engine speed conditions. In the context of the present application, the desired injection pressure is the preferred injection pressure when the engines 121, 122, and 124 are operated under the corresponding engine load and engine speed conditions, wherein the gaseous fuel is pressurized from the storage pressure to the desired injection pressure when the supply pressure is lower than the desired injection pressure. Based on the engine load and engine speed conditions, there may be more than one desired injection pressure. In step 1040, the supply pressure P S and the desired injection pressure P DesInj For comparison. At supply pressure P S Greater than or equal to the desired injection pressure P DesInj In the case of , algorithm 1000 proceeds to dynamic region subroutine 1001 and step 1050, in which gaseous fuel from storage container 130, storage container 130c, storage container 131 or storage container 132 is supplied to gaseous fuel rail 170 so that the actual injection pressure P INJ Basically equal to the supply pressure P S (For example, there may be a small pressure drop across the valve and other components as the gaseous fuel flows from the storage container to the gaseous fuel rail.) Note that the gaseous fuel from storage container 130, storage container 130c, storage container 131, or storage container 132 is supplied directly to gaseous fuel rail 170 via gaseous fuel supply conduit 174 or gaseous fuel supply conduit 173 without compression. Figure 1 , Figure 3 and Figure 4 In the embodiment of the present invention, bypass valves (not shown) around pressure regulators 141, 143, 144, commanded by electronic controllers 191, 192, 193, 194, can be opened to supply gaseous fuel from storage container 130 to gaseous fuel rail 170 without regulation. Figure 4 In the embodiment, the pilot fuel pressure in the pilot fuel rail 280 is still maintained within the differential pressure of the gas fuel pressure in the gas fuel rail 170 by the pressure regulator 144, and the gas fuel is injected at the late stage of the compression stroke, and in particular, the gas fuel is injected within 90 crank angle degrees (CA°) of the top dead center (TDC) during the compression stroke, and more particularly, the gas fuel is injected within 45CA° of TDC during the compression stroke, so that the injected amount of gas fuel is burned in a diffusion combustion mode. In other embodiments, as the storage pressure decreases, the gas fuel from the storage container 130, the storage container 130c, the storage container 131, or the storage container 132 can be adjusted down to the desired injection pressure P DesInj and supply pressure P S, and such downward adjustment may be part of the functionality of pressure regulators 141, 143, and 144. For example, as the storage pressure decreases, the pressure of the gaseous fuel supplied from storage vessels 130, 130c, 131, and 132 may be adjusted downward in discrete steps to a plurality of injection pressures that form a monotonically non-increasing function. In step 1060, the injection parameters are determined using dynamic injection pressure operation, whereby the injection start time and pulse width are selected to vary with the actual injection pressure P INJ (The injection pressure P INJ Can be equal to the supply pressure P S Or the desired injection pressure P DesInj and supply pressure P S The value between ) varies with the injection pressure P rather than the expected injection pressure P DesInj In some embodiments, the method may further include adjusting the desired injection pressure to a predetermined or known first desired injection pressure lower than the first gaseous fuel so as to add fuel to the internal combustion engine at the same engine load and engine speed. The first gaseous fuel contains a lower mol % of hydrogen or even substantially 0 mol % of hydrogen than the fuel supplied to the internal combustion engine. In other embodiments, the mol % of hydrogen in the fuel supplied to the internal combustion engine is known by the controller or otherwise predetermined by the controller, and the desired injection pressure may be provided directly by, for example, a fuel-specific lookup table and a fueling map for the engine load and engine speed. The gaseous fuel is injected late in the compression stroke, and in particular, the gaseous fuel is injected within 90 crank angle degrees (CA°) of top dead center (TDC) during the compression stroke, and more particularly, the gaseous fuel is injected within 45CA° of TDC during the compressor stroke, so that the injected amount of gaseous fuel burns in a diffusion combustion mode. At the supply pressure P S Less than the desired injection pressure P DesInj In the case of a stagnation zone, algorithm 1000 proceeds to static region subroutine 1002 and in step 1070, gaseous fuel from storage container 130, storage container 130c, storage container 131, or storage container 132 is pressurized to a desired injection pressure P before being supplied to gaseous fuel rail 170. DesInj , so that the injection pressure P INJ Equal to the desired injection pressure P DesInj In step 1080, the injection parameters are determined using a static injection pressure operation, whereby the injection start time and pulse width are selected to vary with the desired injection pressure P DesInjThe gaseous fuel is injected at a late stage of the compression stroke, and in particular, the gaseous fuel is injected within 90 crank angle degrees (CA°) of top dead center (TDC) during the compression stroke, and more particularly, the gaseous fuel is injected within 45 CA° of TDC during the compressor stroke, so that the injected amount of gaseous fuel is burned in a diffusion combustion mode.

[0079] In an embodiment with intelligent pressure and operation management, the pressure thresholds for switching between the dynamic region subroutines 1001, 2001 and the static region subroutines 1002, 2002 and when the compressor 220 is actuated in the static region can be determined using predicted operating modes and / or learned usage modes input to the electronic controller 19x for a particular engine, vehicle, fuel composition, operator, and / or geographic location. The desired injection pressure can also be determined to be dependent on the learned usage modes for the internal combustion engine, fuel composition, operator, and / or geographic location. For example, for a system that is refueled at a particular geographic location, the operation of the internal combustion engine operating with the fuel composition previously learned from an earlier refueling operation performed at the same geographic location can be used to determine the desired injection pressure, which can be, at least in part, dependent on the operating mode learned when the internal combustion engine was previously refueled at the same geographic location. In this case, the controller 19x can set the desired injection pressure P for the engine load and engine speed based on the learned operating mode for the fuel composition specific operation. DesInj . Additionally or alternatively, in some exemplary embodiments, the controller may employ intelligent pressure and operation management in a predictive mode. For example, the desired injection pressure may vary with the engine speed required by the internal combustion engine and the predicted engine load. For example, the desired injection pressure is increased when climbing a hill or high load operation is expected; and / or the desired injection pressure is adjusted when the engine speed is expected to be reduced or when the pressure in a particular storage container (130, 130c, 131, 131b, or 132) is expected to be reduced in the event of expected refueling or long-term parking - such as refueling or long-term parking indicated by the operator, geographic location, distance and / or time to the geographic location, or amount of fuel remaining.

[0080] In spark-ignition premixed hydrogen engines, the injection pressure is a fixed value between 2 bar and 30 bar (i.e., a relatively low pressure), and hydrogen is injected upstream of the intake valve during the intake stroke or directly into the combustion chamber early in the compression stroke (i.e., within 90 CA° after the bottom dead center during the compression stroke). These engines operate at a global stoichiometric air / fuel equivalence ratio (λ=1) or at a high air fraction side of the global stoichiometric air / fuel equivalence ratio (λ>1), and these engines cannot reduce the injection pressure by a large amount because these engines are already operating at very low injection pressures, or these engines are already operating at a global rich air / fuel equivalence ratio (λ<1).

[0081] when Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 as well as Figures 7a to 7dWhen the embodiments are used in multi-fuel applications or flexible fuel applications, the types of gaseous fuels used are expanded, the first gaseous fuel includes a gaseous fuel other than hydrogen, and the second gaseous fuel includes hydrogen. The first gaseous fuel may include one of biogas, ethane, methane, natural gas, butane, propane, or a mixture of these fuels. The first gaseous fuel may be any methane-rich gas, such as fossil natural gas or natural gas from renewable resources. In some embodiments, the first gaseous fuel includes less than 1 mol % of hydrogen, and the second gaseous fuel includes 1 mol % to 100 mol % of hydrogen. In some embodiments, the first gaseous fuel includes less than 1 mol % of hydrogen, and the second gaseous fuel has more than 1 mol % of hydrogen. In some embodiments, the first gas fuel includes less than 1 mol % hydrogen and the second gas fuel includes at least 5 mol % hydrogen; or the second gas fuel may include more than 15 mol % hydrogen, or more than 25 mol % hydrogen, or more than 40 mol % hydrogen, or more than 50 mol % hydrogen, or more than 70 mol % hydrogen, or more than 90 mol % hydrogen. The pressure value between the first injection pressure of the first gas fuel and the second injection pressure of the second gas fuel may vary with the mole % of hydrogen in the second gas fuel. The pressure value may also vary with the first gas fuel, such as with the type of gas fuel and whether the first gas fuel includes hydrogen. The pressure value may also vary with the difference between the mole % of hydrogen in the second gas fuel and the mole % of hydrogen in the first gas fuel. In some embodiments, the first gas fuel may contain substantially 0 mol % hydrogen. In some embodiments, the difference between the mole percentage of hydrogen in the second gas fuel and the mole percentage of hydrogen in the first gas fuel can be 5 mole % or more of hydrogen in the second gas fuel than in the first gas fuel; or, the hydrogen in the second gas fuel is 15 mole % more than the first gas fuel, or 25 mole % more than the first gas fuel, or 40 mole % more than the first gas fuel, or 50 mole % more than the first gas fuel, or 70 mole % more than the first gas fuel, or 90 mole % more than the first gas fuel. In some embodiments, the second gas fuel is substantially hydrogen, while in other embodiments, the second gas fuel contains hydrogen, and the second gas fuel may also include one of biogas, ethane, methane, natural gas, butane, propane, or a mixture of these fuels. The first gas fuel may include substantially 0 mole % of hydrogen. In some embodiments, the pressure value between the first injection pressure and the second injection pressure may be greater than 15 bar, in other embodiments, the pressure value may be greater than 20 bar, and in yet other embodiments, the pressure value may be greater than 25 bar, and the pressure value varies with fuel composition and / or engine operating requirements.Depending on the embodiment, at the same engine load and engine speed, the second injection pressure is at least 5% less than the first injection pressure; or at the same engine load and engine speed, the second injection pressure is at least 10% less than the first injection pressure; or at the same engine load and engine speed, the second injection pressure is at least 20% less than the first injection pressure. For the same engine load and engine speed, the percentage reduction in the injection pressure of the second gaseous fuel varies with the mole percentage of hydrogen in the second gaseous fuel, the type of the first gaseous fuel; and / or for the same engine load and engine speed of a particular internal combustion engine, the percentage reduction in the injection pressure of the second gaseous fuel varies with the difference between the mole percentage of hydrogen in the second gaseous fuel and the mole percentage of hydrogen in the first gaseous fuel.

[0082] While particular elements, embodiments, and applications of the present invention have been shown and described, it will be understood that the invention is not limited thereto since modifications may be made by those skilled in the art, particularly in light of the foregoing teachings, without departing from the scope of the present disclosure.

Claims

1. A device for regulating a first gas fuel or a second gas fuel and injecting the first gas fuel or the second gas fuel into an internal combustion engine, the device comprising: a pressure regulator, the pressure regulator being used to adjust the pressure of the first gas fuel or the pressure of the second gas fuel; an in-cylinder fuel injector in fluid communication with the pressure regulator to receive the first gaseous fuel or the second gaseous fuel, the in-cylinder fuel injector being configured to inject the first gaseous fuel or the second gaseous fuel directly into a combustion chamber of the internal combustion engine; and a controller operatively connected to the pressure regulator and the in-cylinder fuel injector, and programmed to: When the internal combustion engine is fueled with the first gaseous fuel: commanding the pressure regulator to adjust the pressure of the first gaseous fuel to a first injection pressure at an engine load and engine speed; and commanding the in-cylinder fuel injector to inject the first gaseous fuel in the first injection amount into the combustion chamber at the first injection pressure within 90 crank angle degrees of top dead center during a compression stroke of the engine; as well as When fueling the internal combustion engine with the second gaseous fuel: commanding the pressure regulator to adjust the pressure of the second gaseous fuel to a second injection pressure at the engine load and the engine speed; and commanding the in-cylinder fuel injector to inject the second gaseous fuel in the second injection amount into the combustion chamber at the second injection pressure within 90 crank angle degrees of top dead center during a compression stroke of the engine; wherein the first gas fuel comprises a gas fuel having a mole percentage of hydrogen that is less than that of the second gas fuel; At the engine load and the engine speed, the second injection pressure is less than the first injection pressure by a pressure value; and The injected amount of the first gas fuel and the injected amount of the second gas fuel are combusted in a diffusion combustion mode.

2. The device according to claim 1, wherein: The first gaseous fuel comprises less than 1 mole percent hydrogen; and the second gaseous fuel comprises more than 1 mole percent hydrogen, and preferably, the second gaseous fuel comprises at least 5 mole percent hydrogen.

3. The device according to claim 1 or 2, wherein: The pressure value varies with the mole percentage of hydrogen in the second gaseous fuel.

4. The device according to any one of claims 1 to 3, wherein: The pressure value varies with the difference between the hydrogen mole percentage of the second gas fuel and the hydrogen mole percentage of the first gas fuel; and preferably, the difference between the hydrogen mole percentage of the second gas fuel and the hydrogen mole percentage of the first gas fuel is that the second gas fuel has 5 mole percentage or more of hydrogen than the first gas fuel.

5. The device according to any one of claims 1 to 4, wherein: The pressure value is a function of the first gaseous fuel type.

6. The device according to any one of claims 1 to 5, wherein: The first gaseous fuel includes substantially 0 mole percent hydrogen.

7. The device according to any one of claims 1 to 6, wherein: The first gaseous fuel includes biogas, ethane, methane, natural gas, butane, propane or a mixture of these fuels.

8. The device according to any one of claims 1 to 6, wherein: The second gaseous fuel is substantially hydrogen.

9. The device according to any one of claims 2 to 6, wherein: The second gaseous fuel also includes biogas, ethane, methane, natural gas, butane, propane or a mixture of these fuels.

10. The device according to any one of claims 1 to 9, further comprising: A storage container, wherein the storage container is used to store gaseous fuel; a compressor in fluid communication with the storage vessel and operable to compress the gaseous fuel from the storage vessel; and a bypass valve in fluid communication with the storage vessel and selectively commanded by the controller to a bypass position to fluidly route the gaseous fuel from the storage vessel around the compressor and to a blocking position to fluidly route the gaseous fuel from the storage vessel through the compressor; wherein the gaseous fuel is the first gaseous fuel or the second gaseous fuel; and the in-cylinder fuel injector fluidly receives the gaseous fuel from the compressor or the bypass valve.

11. The device according to claim 10, wherein: The storage container stores the gaseous fuel as compressed gas.

12. The device according to claim 10, wherein: The storage container stores the first gas fuel as a liquefied gas fuel, and the storage container stores the second gas fuel as a compressed gas.

13. The device according to any one of claims 10 to 12, wherein: When the gas fuel is the first gas fuel, the controller is programmed to: when the pressure of the gas fuel in the storage container is greater than the first injection pressure, command the bypass valve to be in the bypass position to fluidly transfer the gas fuel around the compressor; and when the gas fuel is the second gas fuel, the controller is programmed to: when the pressure of the gas fuel in the storage container is greater than the second injection pressure, command the bypass valve to be in the bypass position to fluidly transfer the gas fuel around the compressor.

14. The device according to any one of claims 10 to 13, wherein: When the gas fuel is the first gas fuel, the controller is programmed to: when the pressure of the gas fuel in the storage container is less than the first injection pressure, command the bypass valve to be in the blocking position to fluidly pass the gas fuel from the storage container through the compressor; and when the gas fuel is the second gas fuel, the controller is programmed to: when the pressure of the gas fuel in the storage container is less than the second injection pressure, command the bypass valve to be in the blocking position to fluidly pass the gas fuel from the storage container through the compressor.

15. The device according to any one of claims 1 to 14, further comprising a hot wire sensor, the hot wire sensor being disposed in a conduit between the storage container and the in-cylinder fuel injector and being operably connected to the controller, the hot wire sensor generating a temperature signal representing the gas fuel in the storage container, wherein: The controller is programmed to receive the temperature signal and determine whether the gaseous fuel is the first gaseous fuel or the second gaseous fuel.

16. The device according to claim 15, wherein: The controller is also programmed to determine a mole percentage of hydrogen in the gaseous fuel.

17. The device of any one of claims 1 to 16, further comprising a switch operable between a first position and a second position, and operably connected to the controller, the controller being programmed to receive a signal from the switch, wherein: When the switch is in the first position, the signal is representative of the first gaseous fuel, and when the switch is in the second position, the signal is representative of the second gaseous fuel.

18. The device according to any one of claims 1 to 9, further comprising: a first storage container, the first storage container being used to store the first gas fuel; a first shut-off valve for selectively fluidly communicating the first gaseous fuel from the first storage container; a second storage container, the second storage container being used to store the second gas fuel; a second shut-off valve for selectively fluidly communicating the second gaseous fuel from the second storage container; a compressor in fluid communication with the first shut-off valve and the second shut-off valve and operable to compress the gaseous fuel from the first storage container or the second storage container; and a bypass valve in fluid communication with the first shut-off valve and the second shut-off valve and selectively commanded by the controller to a bypass position to fluidly pass the first gas fuel from the first storage container or the second gas fuel from the second storage container, respectively, around the compressor and selectively commanded by the controller to a blocking position to fluidly pass the first gas fuel from the first storage container or the second gas fuel from the second storage container, respectively, through the compressor; and The controller is programmed to: command the first shut-off valve to open when fueling with the first gaseous fuel, and command the second shut-off valve to open when fueling with the second gaseous fuel; wherein the second storage container stores the second gaseous fuel as compressed gas; and the in-cylinder fuel injector fluidly receives the first gaseous fuel or the second gaseous fuel from the compressor or the bypass valve.

19. The device according to claim 18, wherein: During fueling with the second gaseous fuel, the controller is programmed to command the bypass valve to the bypass position to fluidly route the second gaseous fuel from the second storage container around the compressor when a pressure of the second gaseous fuel in the second storage container is greater than the second injection pressure.

20. The device according to claim 18 or 19, wherein: During fueling with the second gaseous fuel, the controller is programmed to command the bypass valve to the blocking position to fluidly pass the second gaseous fuel from the second storage container through the compressor when a pressure of the second gaseous fuel in the second storage container is less than the second injection pressure.

21. The device according to any one of claims 18 to 20, wherein: The first storage container stores the first gas fuel as liquefied gas.

22. The device according to any one of claims 18 to 20, wherein: The first storage container stores the first gaseous fuel as compressed gas.

23. The device according to claim 22, wherein: During fueling with the first gaseous fuel, the controller is programmed to command the bypass valve to the bypass position to fluidly route the first gaseous fuel from the first storage container around the compressor when a pressure of the first gaseous fuel in the first storage container is greater than the first injection pressure.

24. The device according to claim 22 or 23, wherein: During fueling with the first gaseous fuel, the controller is programmed to command the bypass valve to the blocking position to fluidly pass the first gaseous fuel from the first storage container through the compressor when a pressure of the first gaseous fuel in the first storage container is less than the first injection pressure.

25. The device according to any one of claims 1 to 24, wherein: The pressure value between the first injection pressure and the second injection pressure is greater than 25 bar.

26. The device according to any one of claims 1 to 25, wherein: At the engine load and the engine speed, the second injection pressure is at least 5% lower than the first injection pressure; or at the engine load and the engine speed, the second injection pressure is at least 10% lower than the first injection pressure; or at the engine load and the engine speed, the second injection pressure is at least 20% lower than the first injection pressure.

27. A method for regulating a first gaseous fuel and / or a second gaseous fuel and injecting the first gaseous fuel and / or the second gaseous fuel in an internal combustion engine, the method comprising: When the internal combustion engine is fueled with the first gaseous fuel: adjusting the pressure of the first gaseous fuel to a first injection pressure under engine load and engine speed; and injecting an injection amount of the first gaseous fuel at the first injection pressure into a combustion chamber of the engine within 90 crank angle degrees of top dead center during a compression stroke of the engine; as well as When fueling the internal combustion engine with the second gaseous fuel: adjusting the pressure of the second gaseous fuel to a second injection pressure at the engine load and the engine speed; and injecting an injection amount of the second gaseous fuel at the second injection pressure into the combustion chamber of the engine within 90 crank angle degrees of top dead center during a compression stroke of the engine; wherein the first gas fuel comprises a gas fuel having a mole percentage of hydrogen that is less than that of the second gas fuel; At the engine load and the engine speed, the second injection pressure is less than the first injection pressure by a pressure value; and The injected amount of the first gas fuel and the injected amount of the second gas fuel are combusted in a diffusion combustion mode.

28. The method according to claim 27, further comprising: determining the gaseous fuel type by receiving a signal indicative of the gaseous fuel type; selecting the first injection pressure at the engine load and the engine speed when the gaseous fuel is the first gaseous fuel; The second injection pressure is selected at the engine load and the engine speed when the gaseous fuel is the second gaseous fuel.

29. The method according to claim 28, wherein: The signal indicative of the gaseous fuel type is from at least one of a fuel type switch, a hot wire sensor, a combustion sensor, a capacitive sensor, a dynamic viscosity sensor, and an acoustic wave and phase detection sensor.

30. The method according to any one of claims 27 to 29, wherein: The first gaseous fuel includes less than 1 mole percent hydrogen; and the second gaseous fuel includes 5 mole percent or more hydrogen.

31. The method according to any one of claims 27 to 30, wherein: The pressure value varies with the mole percentage of hydrogen in the second gaseous fuel.

32. The method according to any one of claims 27 to 31, wherein: The pressure value varies with the difference between the hydrogen mole percentage of the second gas fuel and the hydrogen mole percentage of the first gas fuel; and preferably, the difference between the hydrogen mole percentage of the second gas fuel and the hydrogen mole percentage of the first gas fuel is that the second gas fuel has 5 mole percentage or more of hydrogen than the first gas fuel.

33. The method according to any one of claims 27 to 32, wherein: The pressure value is a function of the first gaseous fuel type.

34. A method according to any one of claims 27 to 33, wherein: The first gaseous fuel includes substantially 0 mole percent hydrogen.

35. The method according to any one of claims 27 to 34, wherein: The first gaseous fuel includes biogas, ethane, methane, natural gas, butane, propane or a mixture of these fuels.

36. A method according to any one of claims 27 to 35, wherein: The second gaseous fuel is substantially hydrogen.

37. The method according to any one of claims 30 to 35, wherein: The second gaseous fuel also includes one of biogas, ethane, methane, natural gas, butane, propane, or a mixture of these fuels.

38. An apparatus for conditioning a gaseous fuel and injecting the gaseous fuel into an internal combustion engine, the apparatus comprising: A pressure regulator, the pressure regulator is used to adjust the pressure of the gas fuel; an in-cylinder fuel injector fluidly receiving a first gaseous fuel or a second gaseous fuel from the pressure regulator, the in-cylinder fuel injector for injecting the gaseous fuel directly into a combustion chamber of the internal combustion engine; and a controller operatively connected to the pressure regulator and the in-cylinder fuel injector, and programmed to: commanding the pressure regulator to adjust the pressure of the gaseous fuel to an injection pressure at an engine load and engine speed; and commanding the in-cylinder fuel injector to inject the gaseous fuel in the injection amount into the combustion chamber at the injection pressure within 90 crank angle degrees of top dead center during a compression stroke of the engine; and Wherein, the gaseous fuel includes hydrogen; The injection pressure is equal to the product of the in-cylinder peak pressure and a multiplication factor, the multiplication factor being in the range of 1.15 to 1.4; and The injected amount is combusted in a diffusion combustion mode.

39. The device according to claim 38, wherein The multiplication factor is in the range of 1.16 to 1.

3.

40. The device according to claim 39, wherein The multiplication factor is in the range of 1.17 to 1.

25.

41. The device according to any one of claims 38 to 40, wherein: The gaseous fuel includes between 15 mol % and 100 mol % hydrogen.

42. The device according to any one of claims 38 to 41, wherein: The gaseous fuel is essentially hydrogen.

43. A method for conditioning a gaseous fuel and injecting the gaseous fuel in an internal combustion engine, the method comprising: regulating the pressure of the gaseous fuel to an injection pressure under engine load and engine speed; and injecting an injection amount of the gaseous fuel at the injection pressure into a combustion chamber within 90 crank angle degrees of top dead center during a compression stroke of the engine; and Wherein, the gaseous fuel includes hydrogen; The injection pressure is equal to the product of the in-cylinder peak pressure and a multiplication factor, the multiplication factor being in the range of 1.15 to 1.4; and The injected amount is combusted in a diffusion combustion mode.

44. The method of claim 43, wherein: The multiplication factor is in the range of 1.16 to 1.

3.

45. The method of claim 43, wherein: The multiplication factor is in the range of 1.17 to 1.

25.

46. ​​A method according to any one of claims 43 to 45, wherein: The gaseous fuel includes between 15 mol % and 100 mol % hydrogen.

47. A method according to any one of claims 43 to 46, wherein: The gaseous fuel is essentially hydrogen.

48. An apparatus for conditioning a gaseous fuel and injecting the gaseous fuel into an internal combustion engine, the apparatus comprising: a storage container that stores the gaseous fuel as a compressed gas; a compressor in fluid communication with the storage vessel to pressurize the gaseous fuel; a bypass valve in fluid communication with the storage vessel and actuatable between a closed position and an open position to bypass the compressor; a gas fuel rail in fluid communication with an output of the compressor and an output of the bypass valve, the gas fuel having an injection pressure in the gas fuel rail; an in-cylinder fuel injector in fluid communication with the gaseous fuel rail and actuatable to introduce fuel directly into a combustion chamber of the internal combustion engine; a first pressure sensor that emits a signal indicative of a supply pressure in the storage vessel or in a supply conduit fluidly connected to the storage vessel upstream of the compressor; a second pressure sensor in fluid communication with a downstream side of the compressor and a downstream side of the bypass valve, the second pressure sensor emitting a signal indicative of a rail injection pressure of the gaseous fuel; and a controller operatively connected to the bypass valve, the in-cylinder fuel injector, the first pressure sensor, and the second pressure sensor, and programmed to: receiving a signal indicative of the supply pressure and a signal indicative of the rail injection pressure; determining a supply pressure of the gaseous fuel based on a signal representing the supply pressure; determining a desired injection pressure based on engine load and engine speed conditions; determining a rail injection pressure of the gaseous fuel based on a signal indicative of the rail injection pressure; as well as When the supply pressure is greater than or equal to the desired injection pressure: actuating the bypass valve to be in the open position; determining an injection parameter based on at least one of the supply pressure and the rail injection pressure; and actuating the in-cylinder fuel injector to introduce fuel into the combustion chamber; When the supply pressure is less than the desired injection pressure: actuating the bypass valve to be in the closed position, whereby the compressor pressurizes the gaseous fuel to the desired injection pressure; determining injection parameters according to the rail injection pressure; and The in-cylinder fuel injector is actuated to introduce fuel into the combustion chamber.

49. The apparatus of claim 48, wherein: The controller is also programmed to: The in-cylinder fuel injector is commanded to inject an injection amount of the gaseous fuel into the combustion chamber at the injection pressure within 90 crank angle degrees of top dead center during a compression stroke of the engine.

50. The apparatus of claim 48, wherein: The controller is also programmed to: The in-cylinder fuel injector is commanded to inject an injection amount of the gaseous fuel into the combustion chamber at the injection pressure within 45 crank angle degrees of top dead center during a compression stroke of the engine.

51. The device according to any one of claims 48 to 50, wherein: The pilot fuel ignites the gaseous fuel.

52. The apparatus of claim 48, further comprising a forced ignition source, and wherein the controller is further programmed to: The in-cylinder fuel injector is commanded to inject directly into a combustion chamber during an intake stroke of the engine, or the in-cylinder fuel injector is commanded to inject within 90 crankshaft degrees after bottom dead center during a compression stroke of the engine.

53. The device according to any one of claims 48 to 52, wherein: The gaseous fuel includes hydrogen, biogas, ethane, methane, natural gas, butane, propane or a mixture of these fuels.

54. A method for regulating and injecting a gaseous fuel in an internal combustion engine, the gaseous fuel being stored as compressed gas in a storage vessel, a first pressure sensor emitting a signal indicative of a supply pressure in the storage vessel or in a supply conduit of the storage vessel fluidly connected to an upstream portion of a compressor, the compressor being in fluid communication with the storage vessel to pressurize the gaseous fuel, a bypass valve being in fluid communication with the storage vessel to fluidly bypass the compressor when the bypass valve is in an open position, a gaseous fuel rail being in fluid communication with a downstream side of the compressor and a downstream side of the bypass valve, a second pressure sensor being in fluid communication with a downstream side of the compressor and a downstream side of the bypass valve, the second pressure sensor emitting a signal indicative of a rail injection pressure of the gaseous fuel, an in-cylinder injector being in fluid communication with the gaseous fuel rail and the in-cylinder injector being operable to introduce the gaseous fuel directly into a combustion chamber of the internal combustion engine, the method comprising: determining the supply pressure based on a signal representing the supply pressure; determining a desired injection pressure based on engine load and engine speed conditions; When the supply pressure is greater than or equal to the desired injection pressure: opening the bypass valve to fluidly deliver the gaseous fuel from the storage vessel to the gaseous fuel rail bypassing the compressor; When the supply pressure is less than the desired injection pressure: closing the bypass valve so that the compressor pressurizes the gaseous fuel to the desired injection pressure; determining the rail injection pressure of the gaseous fuel based on a signal indicative of the rail injection pressure; determining injection parameters according to the rail injection pressure; and The in-cylinder injector is actuated to introduce the gaseous fuel into the combustion chamber.

55. The method of claim 54, wherein: Determining the desired injection pressure is also a function of learned usage patterns regarding the engine, fuel composition, operator, and / or geographic location.

56. The method of claim 54 or 55, wherein: The desired injection pressure is determined also as a function of engine speed demand and predicted engine load of the internal combustion engine.

57. The method of any one of claims 54 to 56 further comprising injecting an injection amount of the gaseous fuel into the combustion chamber within 90 crankshaft degrees of top dead center during a compression stroke of the engine.

58. The method of any one of claims 54 to 56 further comprising injecting directly into a combustion chamber during an intake stroke of the engine, or injecting within 90 crankshaft degrees after bottom dead center during a compression stroke of the engine.

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