Direct injection valve, method of manufacturing a direct injection valve, internal combustion piston engine, method of operating an internal combustion piston engine, and computer control system for operating an internal combustion piston engine

Abstract

The invention relates to a direct injection valve (100) for an internal combustion piston engine (300), the injection valve (100) comprising i. a fuel inlet (102), ii. a fuel passage (104) arranged in flow communication with the fuel inlet (102), iii. a fuel outlet (112) in the fuel passage (104), the outlet (112) comprising one or more injection orifices (112.1, 112.2), iv. a valve needle (114) arranged to close or open the fuel outlet (112), wherein v. the injection valve is for injection of liquid fuel with a lower heating value < 33 MJ / kg, the total cross-sectional area of the fuel outlet (112) is less than 8.5 mm 2 2 / MW, where MW is a cylinder specific nominal maximum power output. The invention also relates to a method of manufacturing a direct injection valve, an internal combustion piston engine, a method of operating an internal combustion piston engine and a control system for operating an internal combustion piston engine.

Description

Technical Field

[0001] This invention relates to a direct injection valve for an internal combustion engine, a method for manufacturing a direct injection valve, an internal combustion piston engine, a method for operating an internal combustion piston engine, and a control system for operating an internal combustion piston engine. Background Technology

[0002] There is a strong market demand for reducing emissions from internal combustion engines, particularly decarbonization. An effective solution for reducing emissions and lowering operating costs from large internal combustion engines in ships and power plants is the so-called dual- or even tri-fuel engine, which can operate on fuels that are carbon-free or contain less carbon, such as traditionally used fossil fuels. These multi-fuel engines offer the flexibility to select the most suitable fuel based on the availability and price of different fuels and / or emission restrictions in a particular place or at a particular time. For example, a ship's engine can operate on non-carbon fuels in areas with strict emission restrictions and on fossil fuel oils elsewhere.

[0003] Traditionally, when operating large diesel or gas engines intended for power generation in land-based power plants or ships, it is generally assumed that fuel injection to ignite the fuel occurs approximately at top dead center (TDC) after the compression stroke. For example, in a diesel engine using LFO as fuel, injection can occur from 25° crank angle (CA) before TDC to 5° CA after TDC, and the injection window is typically about 25° CA long.

[0004] When using generally known principles and experience to select the timing and duration of fuel injection for low-calorific-value fuels, these practices necessitate larger injectors for such fuels to maintain injection timing and duration within conventional ranges, resulting in corresponding power outputs for conventional fuels. This is because narrow injection windows and actual injection pressures require a significant increase in fuel flow rate as a function of time to achieve the desired power output per cylinder of the engine. It has been found that injecting such a large amount of fuel within a narrow window in the TDC region results in a diffuse flame that burns closer to the cylinder walls, increasing component thermal loads. Furthermore, when injectors for both ignition and reserve fuel are required, this leads to an extremely complex cylinder head structure, potentially necessitating three different injectors with different nozzle sizes.

[0005] The object of this invention is to provide a direct injection valve that solves the above-mentioned problems. A further object of this invention is to provide a method for manufacturing a direct injection valve, an internal combustion piston engine, a method for operating an internal combustion piston engine, and a control system for operating an internal combustion piston engine, which solve the above-mentioned problems. Summary of the Invention

[0006] The objectives of the invention can be substantially satisfied as disclosed in the independent claims and in other claims that describe various embodiments of the invention in more detail.

[0007] According to an embodiment of the present invention, a direct injection valve for an internal combustion piston engine, the direct injection valve comprising:

[0008] i. Fuel inlet, ii. A fuel passage, which is arranged to flow in communication with a fuel inlet. iii. A fuel outlet in the fuel passage, the outlet comprising one or more injection orifices, iv. A valve needle configured to close or open the fuel outlet. in v. The injection valve is used to inject liquid fuel with a low calorific value <33MJ / kg, and the total cross-sectional area of ​​the fuel outlet is less than 8.5mm. 2 / MW, where MW is the specific nominal maximum power output of the cylinder.

[0009] Direct injection valves designed in this way allow for the successful injection of alternative liquid fuels with different low calorific values ​​using very similar injectors. This allows for a wide range of fuels with low calorific values ​​and other properties without substantially compromising cylinder power, combustion efficiency, or exhaust emission levels. In practice, using two different alternative fuels has been found to be the most promising way to operate an engine.

[0010] The fuel outlet area in the injection valve is sized based on a specific correlation of the expected maximum nominal power of each cylinder used, which has the lowest calorific value of the fuel to be used. This ensures that the injection valve can inject a sufficient amount of fuel when used with any of the expected fuels, including low-calorific-value and high-calorific-value fuels.

[0011] The total cross-sectional area of ​​the fuel outlet is less than 8.5 mm. 2 By standard MW, the injection valve can inject sufficient quantities of low-calorific-value fuels, such as ammonia, methanol, or ethanol, as fuel in engines producing up to 2500 kW per cylinder. The same valve can also operate the engine at the same power by burning high-calorific-value fuels, such as liquid fuels as the primary fuel.

[0012] The total amount of fuel with the lowest calorific value is most critical in terms of fuel outlet area, as the amount of fuel injected must meet the cylinder's desired power output. In practical applications, some trade-offs may be acceptable, and in such cases, it is conceivable that the standard is for the injection valve to be configured to inject liquid fuel with a low calorific value <33 MJ / kg, and the total cross-sectional area of ​​the fuel outlet to be less than 7.5 mm.2 / MW, where MW is the cylinder-specific nominal maximum power output. The size of this direct fuel injection valve can be compensated for, for example, by increasing the injection duration and / or fuel pressure, which will result in an equal injection quantity of fuel, with a total cross-sectional area of ​​the fuel outlet of 7.5-8.5 mm. 2 / MW without such compensation. In addition to the direct injection valve according to the invention, in practical applications where a separate ignition fuel injection valve is arranged in the engine, corresponding compensation can also be achieved by increasing the amount of fuel injected through the ignition valve. In this way, the desired cylinder power ratio can also be achieved. It has been found that, in practical cases, the lower limit usable in the standard is a total cross-sectional area of ​​the fuel outlet of 2 mm. 2 / MW. In other words, according to one aspect of the invention, the standard can be expressed as the total cross-sectional area of ​​the fuel outlet being set to 2-7.5mm. 2 A value between / MW, or 2-8.5mm by other means. 2 / MW requires little or no compensation.

[0013] According to one aspect of the invention, the area of ​​the fuel outlet is less than 8.5 mm. 2 / MW, where MW is the cylinder-specific nominal maximum power when fuel is directly injected into the combustion chamber of an internal combustion piston engine for compression ignition, using a direct injection valve.

[0014] Direct fuel injection into the cylinder is a preferred embodiment of the invention, and compression ignition provides trouble-free engine operation. Liquid fuels with a low calorific value (<33 MJ / kg) can be effectively ignited by compression ignition by properly arranging the environment in the combustion chamber.

[0015] According to one aspect of the invention, when used at a fuel injection pressure between 600 and 2500 bar, the area of ​​the fuel outlet is less than 8.5 mm. 2 / MW.

[0016] Proper injection pressure ensures sufficient fuel quantity and complete combustion.

[0017] According to one aspect of the invention, the valve includes an accumulator that is in direct communication with the fuel passage and the fuel inlet, the accumulator being integrated into the body of the injector.

[0018] When injecting larger quantities of low-calorific-value fuel, the accumulator near the valve outlet ensures smooth valve function and clean combustion.

[0019] According to one aspect of the invention, a direct injection valve and a second injection valve for injecting a second fuel are arranged in a common body. In this embodiment, the area having a fuel outlet is less than 8.5 mm². 2The valve at / MW is referred to as the first valve.

[0020] In this way, fuel injected via the first valve and fuel injected via the second valve can be injected into the cylinder, with one injector body mounted to the engine cylinder head. This makes installation much easier compared to using a separate injector body.

[0021] According to one aspect of the invention, the direct injection valve is a multi-fuel injection valve configured to inject at least two different liquid fuels, namely a first fuel and a second fuel, wherein the lower heating value of the first fuel is <33 MJ / kg and the lower heating value of the second fuel is ≥33 MJ / kg, preferably ≥42 MJ / kg.

[0022] In practice, when a direct injection valve is assembled in an internal combustion engine to operate the engine alternately with a first fuel or a second fuel, thereby controlling the injection of these fuels through the same injection valve at different times / in different operating modes, the injection duration is controlled so that the fuel injection duration when burning the first fuel is longer than the fuel injection duration when burning the second fuel, and the combustion durations of both the first and second fuels are substantially the same. In this arrangement, a single-size direct injection valve can be used with different fuels without needing to increase the injection pressure of low-calorific-value fuels to a significantly higher pressure range.

[0023] According to one aspect of the invention, a multi-fuel injection valve for an internal combustion piston engine is configured to inject at least two different liquid fuels, a first fuel and a second fuel, including...

[0024] i. Fuel inlet, ii. A fuel passage, which is arranged to flow in communication with a fuel inlet. iii. A fuel outlet in a fuel passage, the outlet comprising one or more injection orifices, iv. A valve needle configured to close or open the fuel outlet. in v. The area of ​​the fuel outlet is less than 8.5 mm. 2 / MW, MW is the cylinder-specific nominal maximum power when used with a fuel having the lowest calorific value among the first and second fuels.

[0025] In this way, the injection valve is used and designed for two fuels with different low calorific values, and the valve is able to inject sufficient amounts of the two fuels to provide substantially equal cylinder power ratios.

[0026] A method of manufacturing a direct injection valve for an internal combustion piston engine includes providing a fuel injector body having

[0027] i. Fuel inlet, ii. A fuel passage, the fuel passage being arranged in flow communication with a fuel inlet, iii. A fuel outlet in a fuel passage, the outlet comprising one or more injection orifices, iv. A valve needle configured to close or open the fuel outlet. And among them Choose at least two fuels intended for use in the engine. Determine the desired cylinder-specific nominal maximum power for cylinders intended to use multi-fuel injection valves. The area of ​​the fuel outlet is set to be less than 8.5 mm. 2 / MW; Where MW is the cylinder-specific nominal maximum power when used with the lowest of the selected fuels having a low calorific value.

[0028] According to one aspect of the invention, the area of ​​the fuel outlet is arranged to be less than 8.5 mm. 2 / MW, where MW is the cylinder-specific nominal maximum power when used with a liquid fuel with a low calorific value of <33MJ / kg.

[0029] The internal combustion piston engine according to the present invention includes at least two cylinders having cylinder heads, the cylinder heads being provided with direct injection valves, the direct injection valves including...

[0030] i. Fuel inlet, ii. A fuel passage, which is arranged to flow in communication with a fuel inlet. iii. A fuel outlet in a fuel passage, the outlet comprising one or more injection orifices, iv. A valve needle configured to close or open the fuel outlet. in v. The injection valve is configured to inject liquid fuel with a low calorific value of <33 MJ / kg, and the total cross-sectional area of ​​the fuel outlet is less than 8.5 mm. 2 / MW, where MW is the cylinder-specific nominal maximum power output configured for the compression ignition of fuel in the combustion chamber of the engine.

[0031] The direct injection valve may include any modifications based on the aspects of the direct injection valve described above.

[0032] Preferably, the internal combustion engine includes a computer control system, which includes a controller computer provided with executable instructions that, when executed by the computer, operate the internal combustion piston engine using the method according to the invention as described below.

[0033] A method of operating an internal combustion piston engine including at least two cylinders, a system for supplying liquid fuel to the cylinders, the system including a first pressure rail connecting a first fuel source and a first high-pressure fuel pump to a first fuel injection valve, wherein the first fuel injection valve includes a direct injection valve for an internal combustion piston engine, the direct injection valve including...

[0034] i. Fuel inlet, ii. A fuel passage, which is arranged to flow in communication with a fuel inlet. iii. A fuel outlet in a fuel passage, the outlet comprising one or more injection orifices, iv. A valve needle configured to close or open the fuel outlet. in v. The injection valve is configured to inject liquid fuel with a low calorific value <33MJ / kg, and the total cross-sectional area of ​​the fuel outlet is less than 8.5mm. 2 / MW, where MW is the rated maximum power output of the cylinder; The method includes operating the engine using at least one of the following operating modes: i. A first operating mode, during which the first liquid fuel and the second liquid fuel are burned by injecting the first liquid fuel into the cylinder via the first fuel injection valve and injecting the second liquid fuel via the second fuel injection valve and igniting the fuel by compression ignition, wherein the first liquid fuel has a lower calorific value than the second liquid fuel.

[0035] ii. A second operating mode, wherein during the second operating mode, the second liquid fuel is burned by injecting a majority of the second liquid fuel into the cylinder via the first fuel injection valve and injecting a second portion of the second liquid fuel into the cylinder via the second fuel injection valve, and igniting the fuel by compression ignition. iii. Third operating mode, in which the mixture is combusted by injecting a mixture of a first liquid fuel and a second liquid fuel into the cylinder via a first fuel injection valve and igniting the fuel mixture by compression ignition. iv. A fourth operating mode, wherein the mixture of the first and second liquid fuels is combusted by injecting a mixture of a first liquid fuel and a second liquid fuel into the cylinder via the first fuel injection valve and injecting a portion of the second liquid fuel into the cylinder via the second fuel injection valve, and igniting the mixture by compression ignition. v. Fifth operating mode, during which the first liquid fuel is burned by injecting the first fuel into the cylinder via the first fuel injection valve and igniting the first fuel by compression ignition.

[0036] In compression ignition, fuel supplied to the combustion chamber is ignited when the temperature, pressure, and resulting chemical environment within the cylinder are suitable for supporting combustion. In diffusion combustion, the fuel supply to the combustion chamber can continue into the combustion phase after ignition. Compression ignition can be implemented using a second fuel, such that the second fuel promotes compression ignition occurring during the injection of the second fuel, and then the second fuel ignites the first fuel. The injection of the first fuel can continue after ignition. Alternatively, compression ignition can be implemented using a second fuel, such that when the environment (temperature and pressure) in the combustion chamber causes fuel ignition, the first fuel and the second fuel are injected into the combustion chamber, and the mixture of the first fuel and the second fuel is compressed and ignited. Again, the injection of at least one fuel can continue after ignition. And as another alternative, when the first fuel is injected into the cylinder through a first fuel injection valve to burn the first liquid fuel, the first fuel becomes compressed and ignited when the conditions (temperature and pressure) in the combustion chamber cause the first fuel to ignite. The injection of the first fuel through the first fuel injection valve can continue after ignition. In the alternatives discussed above, the first fuel and / or the second fuel can be injected sequentially; that is, the fuel in question can be temporarily divided into consecutive shorter injections via the injection valve in question. The injection of the first fuel and the second fuel can be carried out in an overlapping or partially overlapping manner.

[0037] In practice, it is preferable to operate the engine in such a way that at least two of the operating modes i to v are used.

[0038] According to one aspect of the invention, in a first operating mode, the injection duration of the first liquid fuel injected through the first fuel injection valve is 35°CA to 45°CA, and in a second operating mode, the injection duration of the second fuel injected through the first fuel injection valve is 15°CA to 20°CA. In this method, the first fuel injection has a longer duration, but the combustion durations of the first and second fuels are substantially equal.

[0039] Because the dimensions and method steps of the direct injection valve according to the invention define the injection duration using the same injection nozzle for different fuels, the engine can operate well with both the first and second liquid fuels, even if the fuels may have significantly different calorific values. With the help of the invention, the injection duration of low-calorific-value fuels can be extended beyond the conventional injection window without resulting in a deterioration in combustion efficiency or emission levels.

[0040] According to one aspect of the invention, in a first operating mode, the injection timing of the first liquid fuel injected through the first fuel injection valve is 0 to 10°CA before the TDC, and the injection timing of the second liquid fuel injected through the second fuel injection valve is 1°CA to 5°CA before the injection time of the first injection valve.

[0041] According to one aspect of the invention, the lower calorific value of the first fuel is less than 33 MJ / kg, and the lower calorific value of the second fuel is equal to or greater than 33 MJ / kg, preferably greater than 42 MJ / kg.

[0042] A control system for operating an internal combustion piston engine equipped with a direct injection valve according to any one of claims 1 to 6, comprising a controller computer equipped with executable instructions that, when executed by the computer, operate the internal combustion piston engine according to any one of claims 9 to 10.

[0043] The nominal maximum power per cylinder refers to the power output that the engine manufacturer sets as the maximum output power for that cylinder. The total output power of an engine is the sum of the power outputs of all its cylinders. For example, the nominal maximum power of a 6-cylinder engine is six times the nominal power of a single cylinder (power group).

[0044] This invention is particularly advantageous in large internal combustion piston engines operating at low or medium speeds, where absolute time and cylinder volume of a single combustion cycle affect combustion chemistry, thereby allowing for different types of injection phasing compared to smaller engines operating at higher speeds. This invention is also applicable to four-stroke and two-stroke engines.

[0045] It has been found that the combustion of both low-calorific-value and high-calorific-value fuels using the direct injection valve according to the invention is efficient and clean, and also provides equal cylinder-specific power in a medium-speed four-stroke engine having the following details: -rpm range: 300 to 1800rpm -Injection pressure range o Main fuel 600 to 2500 bar LFO as the main fuel bar, for example, 600-2300 bar LHV as the main fuel bar, 600-2500 bar o Ignition fuel pressure of 900 to 2500 bar, preferably higher than the main fuel pressure. - Cylinder bore should be at least 135mm, preferably 150mm-700mm. -Single-cylinder nominal power output: 80 to 2500 kW / cylinder In this invention, it has been surprisingly found that, as is generally understood by those skilled in the art, in the combustion of liquid fuels with significantly low calorific values, the duration of the combustion process does not have the same relationship with the injection duration compared to conventional diesel engines operating with fuels such as heavy, medium, or even light fuel oils. In fact, it has been found that in the combustion of low calorific value fuels, particularly ammonia and methanol, the duration of the combustion process is not directly related to the duration of the fuel injection period.

[0046] This leads to new solutions where the injection duration of this fuel can be extended beyond the conventional range without causing a decline in combustion efficiency or emissions levels. Thus, by properly setting the injection cycle and without requiring compensation operations via significantly different injection pressures, the same, smaller injector can be used for different fuels.

[0047] In this article, the term "main fuel" refers to the fuel that carries most of the energy to the combustion chamber.

[0048] The exemplary embodiments of the invention presented in this patent application should not be construed as limiting the applicability of the appended claims. The verb "comprising" is used in this patent application as an open limitation that does not exclude the presence of features not yet described. Unless otherwise expressly stated, the aforementioned features may be freely combined with each other. Novel features considered to be characteristics of the invention are specifically set forth in the appended claims. Attached Figure Description

[0049] In the following description, the invention will be illustrated with reference to the accompanying exemplary schematic diagrams, wherein...

[0050] Figure 1 A direct injection valve according to an embodiment of the present invention is shown. Figure 2 An arrangement according to an embodiment of the invention is shown in the common body having a second fuel injection valve. Figure 1 The direct injection valve shown is... Figure 3 An internal combustion engine according to an embodiment of the present invention is shown, and Figure 4 An arrangement according to an embodiment of the invention is shown as a single injection valve on the injector body. Figure 1 The direct injection valve shown. Detailed Implementation

[0051] Figure 1A direct injection valve 100 according to the present invention is shown. The first injection valve 100 includes a fuel inlet 102 and a fuel passage 104, the fuel passage 104 being arranged via a fuel inlet to an injector body (…). Figure 1 The flow path 106 (not shown) is in flow communication with the fuel inlet 102. The flow path is preferably provided with a so-called flow fuse 108, which prevents excessive fuel flow in the event of a valve 100 failure. As a preferred feature, the flow path 106 is provided with an accumulator 110 disposed between the fuel passage 104 and the fuel inlet 102. The accumulator 110 is also disposed between the fuel inlet 102 and the flow fuse 108, such that the volume of the flow passage downstream of the flowing fuel (in the normal operating fuel flow direction) is small, and therefore the amount of fuel leakage that may occur in the event of a failure is small. The accumulator is used only for the valve, thus ensuring fuel delivery during injection. The inlet 102 of the direct injection valve 100 is arranged in a controllable flow connection with the first fuel source 16 and the second fuel source 20, which is only used for... Figure 1 This is illustrated schematically. Thus, the fuel injected by the direct injection valve 100 can be selected between the first fuel and the second fuel, or even a mixture of the first fuel and the second fuel can be used.

[0052] Valve 100 is provided with a valve needle 114, which is arranged to close or open fuel outlet 112 by its axial movement. Valve needle 114 is controlled by a hydraulic system 116. The hydraulic system can be implemented in various ways, utilizing the principle of applying a biasing force to the needle against the force generated by the fuel injection pressure. Figure 1 In this embodiment, the hydraulic system is provided with an inlet 118 for pressurized working fluid, which is guided through the inlet 118 to the needle housing at the end of the needle opposite the fuel outlet 112. A pressure chamber 124 is present, defined by the end of the needle 114, such that the pressure of the working fluid exerts a force on the needle 114. An outlet flow passage 122 of the hydraulic system 116 is provided with a valve 120, which, when open, releases pressure from the chamber 124, causing the needle to move upwards as shown in the figure, thereby opening the fuel outlet 112. When the valve 120 is closed, pressure builds up in the chamber 124, forcing the needle 114 back to the closed position. The working fluid also fills a sealed fluid chamber 126 surrounding the upper part of the needle 114 at a pressure higher than the fuel injection pressure to prevent the first fuel from flowing into the hydraulic system 116 and mixing with the working fluid.

[0053] The valve also includes a fuel outlet 112 arranged to lead to a fuel passage 104, which may include one or more injection orifices 112.1, 112.2. As clearly seen in the enlarged cross-section of the valve, the orifices may have a circular cross-section with a diameter defining the geometric cross-sectional area of ​​the orifice. In the presence of multiple orifices, the area A of the outlet 112 is the sum of the areas Ao of each orifice, i.e. .

[0054] The total area A of the fuel outlet is designed to be less than 8.5 mm. 2 / MW, where MW is the cylinder-specific nominal maximum power output, determined based on the engine specifications for which the fuel injection valve is intended to be used. The valve is a multi-fuel injection device, sized to produce substantially equal nominal maximum power for each cylinder of the engine by burning any one of the used fuels in practical applications. In practice, engines typically operate on two different liquid fuels. According to the invention, the area of ​​the fuel outlet 112 is designed based on the cylinder-specific nominal maximum power output when used with the fuel having the lowest calorific value among the different fuels. More precisely, the area A of the fuel outlet 112 is less than 8.5 mm². 2 / MW, where MW is the cylinder-specific nominal maximum power when used with a fuel with a low calorific value <33MJ / kg. The area of ​​region A is determined by considering fuel pressure, resulting in an injection pressure of 600-2500 bar. This pressure range covers the possible variations in fuel viscosity, and when used, the appropriate amount of fuel in each fill can be fine-tuned by the total injection duration. In multi-fuel engines, the fuel pressures of different fuels can be selected to be close to each other, making it easier for these fuels to be directed into the same direct injection valve operating as a multi-fuel injection valve. The fuel pressure of one of the fuels, such as the second fuel (e.g., LFO), can be selected to be slightly higher than the first fuel (a fuel with a low calorific value), allowing the second fuel to be used to displace or flush portions of the fuel system shared by both fuels during fuel switching. This can be important from a safety and maintenance perspective, as some fuels with low calorific values ​​(e.g., ammonia or methanol) have toxic properties.

[0055] For example, an engine is designed to operate using at least two fuels, one of which has a lower calorific value than the other, and the direct injection valve is designed based on the fuel having the lowest calorific value of the first and second fuels. When applied to engines with smaller cylinder bores (such as 200mm), in this case, to determine a cylinder-specific nominal maximum power of 150kW, the area A will be less than 1.275mm². 2Accordingly, when applied to large-bore engines (such as 640mm), in this case, to determine a cylinder-specific nominal maximum power of 1300kW, the area A will be less than 11.05mm². 2 Preferably, the area is designed to be close to the obtained value A of the area to avoid unnecessarily long injection periods; however, some compromises may be acceptable in practice as long as they do not lead to degradation of the combustion process.

[0056] Figure 2 Fuel injector 10 is disclosed, wherein the common body 16 includes, for example, Figure 1 The diagram shows a first injection valve 100 and a second liquid fuel injection valve 200, the second liquid fuel injection valve 200 being configured to inject so-called pilot fuel into the engine at least during normal operation using the first fuel. Typically, the amount of pilot fuel is such that it promotes and ensures compression ignition of the main fuel by influencing the environment within the main combustion chamber. It should be understood that the timing of injection and ignition can be set in many ways. For example, the second fuel ignition can occur before or even during the main fuel (first fuel) injection. The second fuel injection can occur as a single injection period or as a shorter sequential injection period, overlapping or not overlapping between the first and second fuels. Correspondingly, the first fuel injection can also occur as one or more injections within a single combustion cycle. The actual initiation of combustion depends largely on the timing of both the first and second fuel injections, but does not necessarily correspond directly to the start of either injection. Ignition occurs when pressure, temperature, fuel mixture, and the presence of chemically active substances (free radicals) are suitable for ignition and support premixed and / or diffusion combustion. Figure 2 In one embodiment, the second fuel injection valve 200 includes a needle 204 for supplying a second fuel to the combustion chamber of the engine. A second fuel passage 206 is in flow connection to a second fuel inlet 201 via a second fuel supply passage 212. The second fuel supply passage 212 has a second accumulator space 214 disposed in the injector body 16 between the second fuel passage and the second fuel inlet 201. Therefore, the second fuel passage 206 is in flow connection to the second fuel inlet 201 via the second accumulator space 214. The fuel injector unit 10 also contains a hydraulically operated second valve control section 210 disposed at the end of the second fuel injection valve needle 204 opposite to the needle tip. The second fuel supply section can be designed to deliver fuel to the engine's combustion chamber in an amount representing even up to 70-100% of its energy so that the engine can operate at its design load. However, the most important function of the second fuel is to facilitate or provide ignition of the first fuel, in which case it typically represents less than 10% of the total fuel energy entering the cylinder.

[0057] Furthermore, in this embodiment, the second fuel is used as the control fluid for the second valve 202. In other words, the second fuel supply section 200 utilizes the second fuel as the control fluid for the valve. Figure 2 It is clear that the control fluid return lines from both valves are combined to a single outlet 122. This means that in this embodiment, the pressurized working fluid and sealing fluid in the direct injection valve 100 are a second fuel; however, the second fuel is supplied to the first fuel injection valve 100 through a dedicated inlet 108. Thus, the working fluid leading to the first valve can be at a different pressure than the second fuel. This also provides independent pressure control. The sealing fluid chamber 126 in the first fuel injection valve is in continuous flow connection to inlet 118. This ensures that the pressure in the sealing fluid chamber is substantially at a sufficient level and substantially free of pulsations.

[0058] When designing and / or manufacturing a fuel injection valve according to an embodiment of the invention, an injector body 16 is provided, preferably an assembly of multiple components, and a fuel inlet 102 and a fuel passage 114 are provided to the injector body. In this body, the fuel passage 114 is arranged in flow communication with the fuel inlet 102. A fuel outlet 112 is formed at the end of the body 16, through which fuel is injected as a spray. The fuel outlet is arranged to the fuel passage, and the outlet may be provided with one or more injection orifices 112.1, 112.2. A valve needle 114 is axially movable within the body to close or open the fuel outlet 112. The desired cylinder-specific nominal maximum power for a cylinder intended to use the fuel injection valve is determined, and the fuel outlet 112 is provided with a diameter of less than 8.5 mm. 2 / MW is the area where MW is the cylinder-specific nominal maximum power when used with fuel that is intended and / or designed for use in the engine (which has the lowest calorific value among fuels).

[0059] Specifically, MW is the cylinder-specific nominal maximum power when used with a liquid fuel with a low calorific value of <33MJ / kg.

[0060] Figure 2 Also shown is a control system 500 for operating the direct injection valve 100, the second injection valve 200, and the internal combustion piston engine when assembled for use in an engine. The control system includes a controller computer 501 provided with executable instructions that, when executed by the computer, operate the internal combustion piston engine according to the invention. It should be understood that in some practical applications, the second injection valve can be implemented as an injector operated by a telescopic pump, wherein the valve needle opens by fuel pressure provided by a dedicated telescopic pump for the injector.

[0061] Figure 3An internal combustion piston engine 300 is schematically depicted, equipped with a fuel supply system 10 for supplying liquid fuel to two or more cylinders 12. The fuel supply system is suitable for engines with different cylinder configurations, such as inline or V-type engines. The fuel supply system 8 is advantageous for use with liquid fuels, one type being a low-viscosity, low-calorific-value fuel, and the other being a high-viscosity, high-calorific-value fuel. In this regard, the low-viscosity fuel has a viscosity of <1 mm. 2 The viscosity is / s, and the low-calorific-value fuel has a low calorific value of <33MJ / kg. The fuel supply system 8 is particularly advantageous with liquid ammonia or methanol as low-viscosity and low-calorific-value fuels, and as high-viscosity fuels (=>1mm). 2 It can be used with light fuel oil, marine diesel or diesel fuel with high calorific value (=>33MJ / kg) and high calorific value fuel (=>33MJ / kg).

[0062] The fuel supply system 8 includes at least two pressure rails: a first pressure rail 24 and a second pressure rail 28. The pressure rails suppress the desired injection pressure of used fuel. The pressure rails may include an accumulator volume outside the injector as a common rail or partially inside the injector as an injector-specific accumulator. The fuel supply system 8 includes a first fuel source 16 connected to the first pressure rail 24 and at least one first high-pressure fuel pump 18 arranged to pressurize the first fuel in the first pressure rail 24 to the desired injection pressure. Correspondingly, it includes a second fuel source 20 connected to the second pressure rail 28 and at least one second high-pressure fuel pump 22 arranged to pressurize the second fuel in the second pressure rail 28 to the desired injection pressure. The fuel supply system also includes a third pressure rail 40 connected to the second fuel source 20 via a third high-pressure pump 21.

[0063] The fuel supply system includes a first fuel injection valve 100 and a second fuel injection valve 200 for each cylinder of the engine 300. The first fuel injection valve 100 is arranged to be connected to a first pressure rail 24, and the second fuel injection valve 200 is arranged to be connected to a second pressure rail 28.

[0064] In the fuel supply system 8, a first fuel injection valve 100 is configured to inject main fuel into the cylinder 12, which carries most of the heat to the cylinder. According to the invention, the main fuel can be supplied to the first fuel injection valve 100 from either a first fuel source 16 or a second fuel source 20. For functionality, the fuel supply system 8 provides a flow path 32 between a first pressure rail 24 and a second pressure rail 28. The flow path is sized to achieve the required flow rate of the second fuel when used as the main fuel injected by the first valve 100. The fuel supply system is provided with a control valve unit 34, which is configured to control the flow connection between the first pressure rail 24 and the second pressure rail 28 via the flow path 32. Figure 3 In this configuration, the flow path includes a connecting conduit between the first pressure rail 24 and the second pressure rail 28. The third pressure rail 40 is connected to the inlet 118 of the first fuel injection valve 100. The fuel used in the first injection valve 100 can be converted into a second fuel by opening the valve 34 in the conduit 32, which directs the fuel from the second pressure rail 28 through the connecting conduit 32 to the first pressure rail. For this purpose, the pressure in the second pressure rail needs to be higher than the pressure in the first pressure rail.

[0065] In a preferred embodiment, the low-viscosity, low-calorific-value fuel is one of methanol, ammonia, or ethanol, and the high-viscosity, high-calorific-value fuel is one of light fuel oil, marine diesel, marine gas oil, diesel, etc.

[0066] Figure 3 The engine shown is provided with a direct injector valve and a second injection valve according to the invention in each of its cylinders, and the engine can operate, for example, in three different operating modes: A) First operating mode: The first liquid fuel is injected into the combustion chamber as the main fuel through the first injection valve, and the second liquid fuel is injected through the second injection valve to ignite or assist in igniting the first liquid fuel.

[0067] In this mode, the second fuel (ignition fuel) promotes ignition through the compression of the first fuel in the combustion chamber. The first liquid fuel is the primary fuel in combustion, meaning it provides the majority of the energy for combustion.

[0068] Preferably, in this operating mode, the first fuel injection timing range is 0 to 10°CA before TDC, and the first fuel injection duration at nominal load ranges from 35°CA to 45°CA. The ignition timing and duration can be selected based on the fuel. For example, compared to methanol, which can be injected at a duration closer to the lower end of this range, the injection duration of ammonia can be selected from the highest (longest) end of a given range. Naturally, the injection duration and timing are adjusted according to the engine load level.

[0069] During normal engine operation, the injection timing of the second fuel, used as ignition injection, is 1°CA to 5°CA before the injection time of the first injection valve (main fuel), and lasts for 2 to 6°CA. This results in increasing the temperature and pressure in the cylinder to the level required to ignite the first fuel when it is injected into the cylinder.

[0070] For example, under high load conditions, main fuel injection can begin 5 to 10°CA before ignition injection and a split injection strategy can be used, in which approximately 25% of the main fuel is injected 20 to 40°CA before TDC, and the remainder is injected after ignition fuel injection.

[0071] Under high engine load, one possible option is to initiate ignition fuel injection 5°CA to 10°CA after the start of main fuel injection. Furthermore, split injection of the main fuel can be feasible, for example, by implementing a first injection 20°CA to 40°CA before TDC and lasting up to 15°CA, and a second injection within a timing range of 0°CA to 10°CA before TDC, with the duration of the first fuel injection at nominal load ranging from 15°CA to 30°CA.

[0072] B) Second operating mode: The majority of the second liquid fuel is injected into the combustion chamber as the main fuel through the first injection valve, and a portion of the second liquid fuel is injected through the second injection valve.

[0073] Preferably, in this operating mode, the second fuel is injected via the first injection valve within a range of 0 to 10°CA before the TDC, and the duration of the main fuel under nominal load is within a range of 15 to 20°CA.

[0074] Preferably, the second injection valve is also used by injecting a second fuel, such that the injection timing is 1°CA prior to the injection timing of the first injection valve, and the duration is 2°CA. The second injection valve is mainly used in operation to prevent nozzle clogging.

[0075] C) Third operating mode: The mixture of the first liquid fuel and the blend of the second liquid fuel are injected into the combustion chamber through the first injection valve, and a portion of the second liquid fuel is injected through the second injection valve.

[0076] Figure 4 A fuel injector 10 is disclosed, wherein the main body 16 includes, for example, Figure 1 The first injection valve 100 shown is the only injection valve in the engine cylinder. The inlet 102 of the direct injection valve 100 is arranged in a controllable flow connection with the first fuel source 16 and the second fuel source 20, which only... Figure 1This is illustrated schematically. Thus, the fuel injected by the direct injection valve 100 can be selected between the first fuel and the second fuel, or even a mixture of the first fuel and the second fuel can be used.

[0077] Using this embodiment, an engine can be operated such that liquid fuel, a first fuel, or a second fuel can be burned as needed by injecting a first fuel into the engine cylinder via a first fuel injection valve and igniting the fuel through compression ignition. Ignition occurs when the pressure, temperature, fuel-air mixture, and the presence of chemically active substances (free radicals) are suitable for ignition.

[0078] While the invention has been described by way of example with reference to embodiments currently considered to be the most preferred, it will be apparent to those skilled in the art that the basic idea of ​​the invention can be implemented in many ways, along with technological advancements. Therefore, the invention and its embodiments are not limited to the examples and samples described above, but can be varied within the scope of the patent claims and their legal equivalents. When such a combination is technically feasible, the details mentioned in any of the foregoing embodiments can be used in conjunction with another embodiment.

Claims

1. A direct injection valve (100) for an internal combustion piston engine (300), the direct injection valve (100) comprising: i. Fuel inlet (102). ii. A fuel passage (104) arranged in flow communication with the fuel inlet (102), iii. A fuel outlet (112) in the fuel passage (104), the outlet (112) comprising one or more injection orifices (112.1, 112.2). iv. Valve needle (114), which is arranged to close or open the fuel outlet (112). in v. The injection valve is configured to inject liquid fuel with a low calorific value <33 MJ / kg, and the total cross-sectional area of ​​the fuel outlet (112) is less than 8.5 mm. 2 / MW, where MW is the specific nominal maximum power output of the cylinder.

2. The direct injection valve (100) according to claim 1, wherein, The injector is sized to be used in an internal combustion piston engine (300) that uses compression ignition and has a nominal power output of at least 80 kW / cylinder, where MW is the cylinder-specific nominal maximum power when the fuel is injected directly into the combustion chamber.

3. The direct injection valve (100) according to claim 1, wherein, When used at fuel injection pressures between 600 and 2500 bar, the area of ​​the fuel outlet (112) is less than 8.5 mm. 2 / MW.

4. The direct injection valve (100) according to claim 1, wherein, The valve (100) includes an accumulator (110) between the fuel passage (104) and the fuel inlet (102), the accumulator (110) being integrated into the body (16) of the injector.

5. The direct injection valve (100) according to any one of claims 1 to 4, wherein the direct injection valve and the second injection valve (200) for injecting the second fuel are arranged in a common body (16).

6. The direct injection valve (100) according to any one of claims 1 to 4, wherein, The direct injection valve (100) is a multi-fuel injection valve, which is configured to inject at least two different liquid fuels, a first fuel and a second fuel, wherein the lower heating value of the first fuel is <33MJ / kg and the lower heating value of the second fuel is ≥33MJ / kg, preferably ≥42MJ / kg.

7. A method of manufacturing a direct injection valve (100) for an internal combustion piston engine (300), the method comprising providing a fuel injector body having v. Fuel inlet (102). vi. Fuel passage (104), which is arranged to be in flow communication with the fuel inlet (102). vii. The fuel outlet (112) in the fuel passage (104), the outlet (112) comprising one or more injection orifices, viii. Valve needle (114), which is arranged to close or open the fuel outlet (112). And in the method Select at least two fuels to be used in the engine (300). Determine the desired cylinder-specific nominal maximum power for the cylinder to which the direct injection valve (100) will be used. The area of ​​the fuel outlet (112) is set to be less than 8.5 mm. 2 / MW, Where MW is the cylinder-specific nominal maximum power when used with the lowest of the selected fuels having the lowest calorific value.

8. The method according to claim 6, wherein, Less than 8.5mm 2 / MW, where MW is the cylinder-specific nominal maximum power when used with a liquid fuel with a low calorific value of <33MJ / kg.

9. An internal combustion piston engine (300) comprising at least two cylinders having cylinder heads, the cylinder heads being provided with direct injection valves according to any one of claims 1 to 6, the direct injection valves being configured for compression ignition of fuel in the combustion chamber of the engine.

10. The internal combustion piston engine (300) according to claim 9, wherein the internal combustion piston engine includes the computer control system according to claim 16.

11. A method of operating an internal combustion piston engine (300), the internal combustion piston engine (300) comprising at least two cylinders (12), a system for supplying liquid fuel to the cylinders (12), the system comprising a first pressure rail (24) connecting a first fuel source and a first fuel high-pressure pump (18) to a first fuel injection valve (100), and wherein the first fuel injection valve comprises a direct injection valve (100) according to any one of claims 1 to 6, the method comprising operating the engine using at least one of the following operating modes: i. A first operating mode, during which the first liquid fuel and the second liquid fuel are burned by injecting a first liquid fuel into the cylinder via the first fuel injection valve (100) and injecting a second liquid fuel via the second fuel injection valve (200) and igniting the fuel by compression ignition, wherein the first liquid fuel has a lower calorific value than the second liquid fuel. ii. A second operating mode, wherein during the second operating mode, the second liquid fuel is burned by injecting a majority of the second liquid fuel into the cylinder via the first fuel injection valve (100) and a second portion of the second liquid fuel into the cylinder via the second fuel injection valve (200), and by igniting the fuel through compression ignition. iii. A third operating mode, during which the mixture is burned by injecting a mixture of the first liquid fuel and the second liquid fuel into the cylinder via the first fuel injection valve (100) and igniting the fuel mixture by compression ignition. iv. A fourth operating mode, during which the mixture is burned by injecting a mixture of the first liquid fuel and the second liquid fuel into the cylinder via the first fuel injection valve (100) and injecting a portion of the second liquid fuel into the cylinder via the second fuel injection valve (200) and igniting the mixture by compression ignition. v. Fifth operating mode, during which the first liquid fuel is burned by injecting the first fuel into the cylinder via the first fuel injection valve (100) and igniting the first fuel by compression ignition.

12. The method according to claim 11, wherein, The method includes operating the engine alternately using at least two of the operating modes i to v.

13. The method according to claim 11, wherein, In the first operating mode, the injection duration of the first liquid fuel injected through the first fuel injection valve (100) is 35°CA to 45°CA, and in the second operating mode, the injection duration of the second fuel injected through the first fuel injection valve (100) is 15°CA to 20°CA.

14. The method according to claim 11 or 13, wherein, In the first operating mode, the injection timing of the first liquid fuel injected through the first fuel injection valve (100) is 0 to 10°CA before the TDC, and the injection timing of the second liquid fuel injected through the second fuel injection valve (200) is 1°CA to 5°CA before the injection time of the first injection valve (100).

15. The method according to claims 11 to 14, wherein, The lower heating value of the first fuel is less than 33 MJ / kg, and the lower heating value of the second fuel is equal to or greater than 33 MJ / kg, preferably greater than 40 MJ / kg.

16. A computer control system (500) for operating an internal combustion piston engine equipped with a direct injection valve (100) according to any one of claims 1 to 6, the computer control system comprising a controller computer provided with executable instructions, which, when executed by the computer, operate the internal combustion piston engine using the method according to any one of claims 11 to 15.

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