JP6100290B2 - Method for operating an internal combustion engine and internal combustion engine operated by the method - Google Patents

Description

  The invention comprises a cylinder with a reciprocating piston in each interior and a combustion chamber above the piston, and at least one fuel injector that injects fuel directly into the combustion chamber above the piston during operation. The engine is operated with exhaust gas recirculation and is sometimes operated in an environment with a first emission standard that limits the emission of pollutant components along with the exhaust gas. Operated at different times in another environment with a second, more stringent emission standard that limits the emission of such polluting components.

  WO-A-2009 / 046713 discloses a method and apparatus for controlling a dual fuel compression ignition engine, whereby the engine is adjusted to adjust fuel quality in order to adjust the timing of ignition. Fuel is mixed from different components. Accordingly, a fuel mixing unit is disclosed.

Both the EP-B-0459983 and EP-B-0553364 discloses a device for injecting a mixture of fuel and water in the diesel engine, whereby the fuel and water, the black smoke and NO _x In order to reduce at the same time, it is alternately injected at closely spaced intervals.

  US Patent Application Publication No. 2011/0288744 relates to an engine comprising an exhaust gas recirculation pipe, an exhaust gas recirculation valve, and a fuel injection system operable with several fuels. The controller controls operation such that specific fuel consumption is reduced while at the same time exhaust emissions and components in the engine operate within threshold limits.

In general, the present invention aims to reduce NO _{x in} the exhaust gas of internal combustion engines. The exhaust gas of an internal combustion engine is subject to regulations regarding the content of various pollutants, such as NO _x, and it is generally undesirable to emit particulate matter (PM) or soot.

The United Nations organization, the International Maritime Organization (IMO), has set limits on emissions, known as primary, secondary and tertiary regulations. emission standards of the following regulatory and secondary regulation is a globally effective, emission standards cubic regulations apply only to NO _x emission regulations sea (ECA). NO _x emission standards of the secondary regulation and tertiary regulation is effective for the new engine, the NO _x requirements of the primary regulation, valid for existing engines made before the year 2000 is there.

  Therefore, a self-propelled ship such as a ship that sails around the world may be in a secondary-regulated sea area, that is, in an environment where the secondary regulation is applied, or in another environment where the tertiary regulation is applied. There are other times in (ECA), and many ECAs are defined for coastal areas.

Exhaust gas recirculation (EGR) comprises at least one piston that reciprocates within an individual cylinder and a combustion chamber above the piston, and injects fuel directly into the combustion chamber above the piston during operation. It is known to be an effective way to reduce NO _x emissions from an internal combustion engine with two fuel injectors.

During operation of the internal combustion engine, a cylinder charge comprising a mixture of incoming air and recirculated exhaust gas is taken into the combustion chamber and fuel spray is delivered to the combustion chamber at the appropriate time for the engine's operating cycle. The injected fuel ignites and creates a combustion zone in the combustion chamber. The incoming air comprises oxygen, whereas the recirculated exhaust gas is free of oxygen or has a low content of oxygen. On the other hand, the recirculated exhaust gas is relatively rich in water vapor and carbon dioxide as compared to the incoming air. Therefore, cylinder filling has relatively low oxygen content, relatively high water vapor and carbon dioxide content, and low oxygen content compared to conventional inflow air without exhaust gas recirculation. and if both the large water vapor and carbon dioxide of content, lowering the combustion temperature and, since most of the NO _x is formed through a thermal path, the pure flowing air is used in the cylinder charge In comparison, it is a factor that reduces the formation of NO _{x in} the combustion region. Exhaust gas recirculation shows the potential to reduce the NO _x emissions to a maximum of 80%.

  However, as exhaust gas recirculation is increased, the formation of particulate matter (PM) or soot and, in addition, the formation of carbon monoxide increases, which is undesirable and is a limitation on the degree of exhaust gas recirculation. Will be provided.

An object of the present invention, at the same time leads to a further reduction of the NO _x emissions from an internal combustion engine with exhaust gas recirculation of the high degree, for use in environments where additional reduction of the NO _x emissions is required, the soot It is to suppress excessive discharge of particles.

To achieve this, the method according to the invention as mentioned by [technical field]
a) when operating in an environment having the first emission standard, the engine is operated with a first fuel having a first low heating value and with a first degree of exhaust gas recirculation; ,
b) when operating in another environment having the second more stringent emission standard, the engine is a second fuel having a second low heat value that is lower than the first low heat value; and Being operated at a second degree of exhaust gas recirculation higher than the degree one exhaust gas recirculation;
For a given engine load, fuel injection occurs at an earlier engine cycle timing when the internal combustion engine is operating with the second fuel than when the internal combustion engine is operating with the first fuel. It is characterized by being started.

When the engine is operated in the other environment having a second emission standard, the second fuel is injected into the cylinder and a second higher degree of exhaust gas recirculation is applied. A higher degree of exhaust gas recirculation causes a further reduction in the formation of NO _x during the combustion process and thus complies with the lower limits on NO _x emissions set by the second emission standard, while soot particles Suppressing excessive amounts of emissions results from the effect of injecting a greater amount of fuel for a given engine load.

  The soot formation caused by a large amount of exhaust gas recirculation is due to the combustion zone subject to oxygen deficiency, which limits the possibility of reoxidation of soot particles already formed and also carbon monoxide It also limits the further oxidation of to carbon dioxide. By using the fuel at a relatively low heat value, a greater amount of fuel can be injected to obtain a given energy output. Because more fuel is injected into the cylinder filling in the combustion chamber and fuel injection occurs at higher pressures, more fuel injection will cause the combustion chamber contents to stir more strongly, resulting in greater mass The cylinder filling is taken into the combustion region. Thus, with respect to the calorific value of the injected fuel, the larger volume of injected fuel increases the cylinder filling mix into the actual combustion zone, which is caused by the increased degree of exhaust gas recirculation. To compensate for the decrease in oxygen content of the filling.

Thus, the amount of oxygen actually required for combustion will be present in the combustion zone, and soot formation will be suppressed or even avoided. Furthermore, the required limit of NO _x formation is achieved thanks to the increased degree of exhaust gas recirculation, whereby the limits of NO _x emission control sea areas can be met. When an internal combustion engine is operated outside the NO _x emission control area, the use of a relatively high low calorific first fuel minimizes specific fuel consumption, which is also an important environmental requirement (engine In the sense of the weight of fuel per effect produced).

  For a given engine load, fuel injection is initiated at an earlier engine cycle timing when the internal combustion engine is operating with the second fuel than when the internal combustion engine is operating with the first fuel. The The second fuel having a calorific value lower than that of the first fuel can be injected in a larger amount than the first fuel, so that the same energy release and combustion effect can be caused in the combustion chamber. The earlier start of fuel injection is that when using the second fuel, the second fuel can be injected through the same fuel nozzle shape as the first fuel injection, and the second fuel is injected into the engine cycle. The same maximum pressure can be applied during This simplifies the engine cylinder design. The cylinder may be provided with more injectors, and one or more injectors can be operating when the second fuel is used, or individual injectors can be The spray nozzle can be embodied with an adjustable spray region.

  Preferably, the second low calorific value of the second fuel is less than 90% of the first low calorific value of the first fuel, so that a corresponding larger volume of the second fuel is present. , Injected for a given engine load.

  In an embodiment, the second fuel is a mixture comprising the first fuel as the first component and at least one other component having a low calorific value that is lower than the low calorific value of the first fuel. This achieves that the change from the first fuel to the second fuel can be carried out by mixing at least one other component into the first fuel stream. It is also an advantage that storage of multiple types of fuel is simplified by using the first fuel as part of the second fuel.

  In an embodiment, the second fuel comprises an incombustible component. The non-flammable component can be the at least one other component of the second fuel. A non-flammable component may have a low calorific value of zero and is therefore a very effective regulator of the calorific value of a mixture of a first component that is flammable.

  In the embodiment, the change from the first fuel to the second fuel is gradually performed. This allows a simple switch to the second fuel by gradually adding one or more other components to the first fuel to provide a mixture of the second fuel.

  In an embodiment, the first fuel comprises a liquid fuel and the second fuel comprises a distillate fuel emulsified with water, a residual fuel emulsified with water, alcohol, ammonia, dimethyl ether, and mixtures thereof. With a fuel selected from This embodiment is advantageous for engines with liquid fuel injectors.

  In other embodiments, the first fuel comprises a fuel gas and the second fuel is selected from the group comprising a low heating value boil-off gas, synthesis gas, a gas mixed with an inert gas, and mixtures thereof. Gas fuel is provided. This embodiment is advantageous by engines with fuel injectors based on gas injection or with dual fuel injectors that inject pilot fuel to cause ignition and then inject gas as the main fuel.

  Liquid fuel or gaseous fuel is used according to the specifications of the internal combustion engine. In the case of liquid fuel, the water emulsified into combustible constitutes the non-combustible component of the second fuel. In the case of gaseous fuel, an inert gas such as nitrogen that does not participate in combustion constitutes the incombustible component of the second fuel.

  In an embodiment, the internal combustion engine is a low speed two-stroke crosshead diesel internal combustion engine. A low speed engine is an engine that operates at a rotational speed in the range of 40 to 300 rpm, in particular at a rotational speed between 40 and 250 rpm, at 100% engine load. The expression “diesel” is to be understood as comprising an engine that operates according to a diesel cycle, which is exemplified by diesel fuel, heavy oil fuel, gas fuel such as methane or natural gas, or dual fuel. That is, it can operate with self-igniting pilot fuel and non-self-igniting main fuel.

  In another embodiment, the internal combustion engine is a medium speed four stroke internal combustion engine. A medium speed engine is an engine that operates at a rotational speed between 300 and 1200 rpm, in particular at a rotational speed between 400 and 1000 rpm, at 100% engine load.

  In an embodiment, for a given engine load, the fuel injection is for the engine cycle when the internal combustion engine is operating with the second fuel rather than when the internal combustion engine is operating with the first fuel. Performed while the percentage is larger. The lower heating value of the second fuel and, consequently, the greater amount of fuel that needs to be injected per engine cycle to obtain the same engine load, during a larger percentage of the engine cycle, Thus, it can be done by injecting fuel during a long period of time when the engine is operating at a constant rotation (rpm). Alternatively, the injector is provided with a larger injection area so that a larger volume of the second fuel can be injected with the same injection profile as the injection profile for the first fuel with respect to the crank angle. May be.

Furthermore, the region on the local earth, according to the actual weather conditions, may be comply with different standards for discharge of NO _x. Therefore, internal combustion engines located in such local terrestrial areas sometimes operate in an environment with a first emission standard, and the fact that the environmental standard changes with actual weather conditions. Thus, with respect to acceptable emissions of such pollutant components of exhaust gas, you are operating at different times in another environment with a second, more stringent emission standard. Such a shift in emission standards due to environmental changes at a particular earth location may be related to an internal combustion engine operating as a ship's propulsion engine or auxiliary engine, but is driven by the internal combustion engine. It is even more relevant to an internal combustion engine that operates as a prime mover in a fixed power generation facility that sends power to the power grid by a generator.

  Examples of the invention and embodiments of the invention are described in more detail below with reference to the very schematic drawings.

Sectional drawing of the perpendicular direction of the cylinder of an internal combustion engine. FIG. 2 is an exemplary diagram for exhaust gas recirculation in the internal combustion engine of FIG. 1. The figure of the embodiment of the combustion chamber and fuel supply system in a cylinder. Figure of soot concentration as a function of exhaust gas recirculation. The figure which shows how the taken-in air depends on the low calorific value of the fuel injected.

  The method according to the invention is based on an engine of the MC or ME type as an example of the manufacture of MAN Diesel & Turbo, or an engine of the X, RT-flex or RTA type as an example of the manufacture of Wartsila or an engine manufactured by Mitsubishi Heavy Industries Are related to internal combustion engines of the type of two-stroke crosshead diesel engine. This type of engine is a large engine typically used as a ship's main engine or as a fixed engine in a power plant. The cylinder may have a bore ranging from, for example, 25 cm to 120 cm, and the engine may have an output ranging from, for example, 3000 kW to 120,000 kW. Such engines are low speed engines with engine speeds ranging from 40 rpm to 250 rpm, or engine speeds up to 300 rpm. Also, the method according to the present invention can be used for 32 / 44CR type, 48 / 60DF type, 51 / 60DF type, V28-33D type engine as an example of MAN Diesel & Turbo manufacture, or 20 type to 64 type as an example of Wartsila manufacture. Also associated with 4-stroke diesel engines, such as DF type engines, which have engine speeds in the range of, for example, 300 rpm to 1200 rpm.

  In FIG. 1, the exhaust valve 1 mounted on the cylinder cover at the top of the engine cylinder 6 is shown in a state where the piston is at the bottom dead center position (BDC) in the open position. The scavenging port at the lower part of the air flow allows the incoming air from the scavenging receiver 3, ie the incoming air / gas mixture, to flow into the cylinder in a swiveling movement, and the combustion gas product through the exhaust valve to the exhaust gas receiver. 7 (black arrow), from which the exhaust gas flows through the turbine section of the turbocharger 2. The compressor section of the turbocharger 2 sucks inflow air (white arrow), and sends the compressed inflow air to the scavenging receiver 3 through the gas cooler 4 and the water mist trap 5.

  In the following, the same symbols will be used for the same type of details, however, for ease of explanation, some symbols will be referred to as the letters a and b when related to the details arranged or operated in parallel. Can be identified.

  The engine is operated with exhaust gas recirculation (EGR). An example of a configuration for this is shown in FIG. Although two turbochargers 2a, 2b are shown, the engine may comprise only one turbocharger or more than two turbochargers, such as three, four or five. The turbocharger 2a is a secondary turbocharger that can be excluded from operation by closing the two control valves 13, and one of the two control valves 13 is arranged in an exhaust gas pipe upstream of the turbine section. The other is disposed in the inflow air pipe downstream of the compressor section. The turbocharger 2b is a basic turbocharger. The secondary turbocharger can be operated when the engine load is high and can be excluded from operation when the engine load is low.

  In the illustrated example, the engine comprises six cylinders, each cylinder sending exhaust gas to the exhaust gas receiver 7. The turbochargers 2a and 2b can be supplied with exhaust gas from an exhaust gas receiver. An exhaust gas recirculation pipe 10 from the exhaust gas receiver 7 is selectively used to remove undesired components from the exhaust gas before it is sent to the shut-off valve 8 and the inflow air pipe downstream of the control valve 13. And a first cleaning device 9. A second cleaning device 11 can be placed between the gas cooler 4 and the water mist trap 5a to further remove unwanted components from the recirculated exhaust gas. The blower 17 can send the recirculated exhaust gas to the scavenging receiver 3 at a low engine load or the like. The EGR blower 14 having a larger capacity than the blower 17 passes the recirculated exhaust gas from the water mist trap 5a via the control valve 18 to the inflow air pipe from the turbocharger 2b at a position downstream of the gas cooler 4b. Can be sent. The recirculated exhaust gas passes through both the water mist trap 5a and the water mist trap 5b before entering the scavenging receiver 3.

  The auxiliary blower 16 is connected to the inflow air pipe from the turbocharger 2b, and the auxiliary blower 16 is efficiently connected to the turbocharger 2 because, for example, the speed of the exhaust gas flow is very low during engine startup. It can be used at very low engine loads that cannot be supplied. A check valve 15 is provided in each pipe supplied to the scavenging receiver. The six cylinders are shown with arrows that are supplied with incoming air / gas from a scavenging receiver.

  In the exhaust gas recirculation, the secondary turbocharger 2a is omitted together with the control valve 13 and the blower 17, and the EGR blower 14 is connected to the inlet air pipe from the turbocharger 2b at a position downstream of the water mist trap 5b. It may be provided in other ways, such as a configured.

  The pistons 19 reciprocate within the individual cylinders 6 during engine operation. As shown in FIG. 3, one or more fuel injectors 22 are mounted on the cylinder cover to inject fuel directly into the combustion chamber 20 present in the cylinder above the piston, etc. Is arranged. The fuel is sent to the individual fuel injectors via the fuel supply line 23 when the control device 24 sends the fuel to the injectors. The control device 24 is in electronic communication with the control unit 26 via a signal line 25. The engine may comprise a single control unit or several control units, such as a cylinder control unit for individual cylinders and possibly one or more central control units. Fuel to the fuel injector 22 is sent from a fuel supply system. This feeding can be done in several different ways. One possibility is to deliver the fuel at a relatively low pressure, such as a supply pressure ranging from 2 to 25 bar, and then deliver the fuel to the injector at a high pressure such as 800 bar at the desired timing in the engine cycle. The use of high-pressure fuel pumps associated with the individual injectors. The high pressure fuel pump may be of the Bosh type and may be hydraulic or camshaft operated. Another possibility is to provide fuel at the high pressure required for injection into the common rail 31 which can be supplied by individual injectors opening and closing control valves.

  The fuel supplied to the fuel injector 22 has a composition that depends on the environment in which the internal combustion engine is currently operating. The first fuel source 27 holds a first fuel having a first calorific value. The second fuel source 28 holds a second fuel or fuel component having a second calorific value lower than the first calorific value of the first fuel. The mixing unit 29 mixes the first fuel and the second fuel according to the control signal received through the signal line 30 from the control unit 26, or an equivalent control unit such as a central control unit The composition is controlled and another local control unit controls the operation of the fuel injectors in the individual cylinders.

  The first fuel is a fuel having a first calorific value. The second fuel is a fuel having a second calorific value. This second fuel may be supplied as another fuel that is completely independent of the first fuel. However, the second fuel may be a mixture, in which case the first fuel is utilized as the first component in the component of the mixture with respect to the second fuel, and the first component is the first component. Mixed with at least one other component having a lower heating value than the component.

  One other component may be a non-flammable component such as water or an inert gas, and in both cases the non-flammable component contributes to lowering the second low heating value of the second fuel. To do. The first fuel can be a heavy oil fuel having a low heating value of 40.9 MJ / kg or a medium grade oil having a low heating value of 42.9 MJ / kg. Medium grade oil mixed with 25% water can be supplied as the second fuel and has a low heating value of 32.2 MJ / kg. Medium grade oil mixed with 40% water could be supplied as the second fuel and has a low heating value of 25.7 MJ / kg. When the engine is operated with gas, the first fuel may be butanol having a low heating value of 33 MJ / kg and the second fuel is methanol having a low heating value of 19.5 MJ / kg, or , A mixture of butanol and an inert gas such as nitrogen, or ammonia having a low heating value of 18.6 MJ / kg.

Internal combustion engine, such as a maximum limit relating to NO _x emissions 14.4 g / kWh, when operating in the environment of the first emission standards, engine, a first fuel, and the like recirculation of 25% 1 Of exhaust gas recirculation. When the engine is subsequently operated in an environment with a second emission standard, such as a maximum limit for NO _x emissions of 3.4 g / kWh, the engine is second fuel and such as 50% recirculation Operated with a second degree of exhaust gas recirculation. A high degree of exhaust gas recirculation has the negative effect that soot formed during combustion in the combustion chamber is not removed again before the exhaust gas leaves the engine. When the combustion product is mixed with a gas containing oxygen, carbon monoxide reacts with oxygen, carbon dioxide is formed, and soot is removed.

  Injection of a second fuel having a low level of low heating value is performed by injecting a larger volume of fuel to meet the engine's requirements for fuel at a given engine load. Fuel injection is set to start earlier in the engine's operating cycle so that more time is available for injection, and instead of injecting via three injectors per cylinder A larger injection nozzle area may be utilized, such as by injecting through four injectors. Fuel injection is set to start at a crank angle of 2 ° before top dead center (TDC) when the first fuel is injected, for example, when the second fuel is injected, For example, it is set to start at a crank angle of 5 ° before top dead center (TDC). Therefore, the timing of the start of fuel injection is earlier in the engine cycle when the internal combustion engine is operating with the second fuel than when the internal combustion engine is operating with the first fuel. The earlier timing of the start of the second fuel injection is given in the example at 3 ° (from 2 ° to 5 ° before TDC = 3 ° earlier), but the earlier timing is Earlier in the range of 0.1 ° to 15 ° from the start of the fuel injection, preferably earlier in the range of 1 ° to 8 ° from the start of the first fuel injection, etc. Other values can be taken. The control unit 26 can provide the control device 24 with a signal for the start of injection. The control unit 26 receives information about the current position of the crankshaft of the engine from a rotation detector associated with the crankshaft and the timing of the start of injection in the engine cycle is 4 ° before TDC or 7 before TDC. It is determined in relation to the TDC position, such as °.

  The duration of the fuel injection can also be performed during a greater percentage of the engine cycle when the engine is operating with the second fuel. The duration is not only by starting fuel injection earlier in the cycle, but also in the cycle when the internal combustion engine is operating with the second fuel than when the internal combustion engine is operating with the first fuel. It can also be made longer by ending fuel injection later in the engine cycle, such as slower crank angle by 3 °.

  Soot formation as a function of the degree of exhaust gas recirculation is shown in FIG. Curve A, shown as a solid line, shows how the soot concentration can increase when exhaust gas recirculation exceeds 40%. Curve B shown by the dashed line shows the effect on soot concentration that results from using a second fuel that is injected at a volume greater than the first fuel. The greater volume and greater mass of the second fuel cause a higher degree of agitation of the contents of the combustion chamber due to fuel injection. Since the injected fuel takes in air from outside the combustion region and brings this air into the combustion region, it also draws oxygen contained in the air into the combustion region where oxygen acts to remove soot. The injected fuel has an energy content that can be expressed in kJ. In order to operate the engine at a certain engine load, a certain energy content of fuel needs to be injected into the combustion chamber. The mass of air entrapped into the combustion zone per injected kJ of fuel energy content as a function of the low calorific value at MJ / kg of the second fuel is shown in curve C in FIG. Is shown as It can be seen that the mass of air increases as the low heating value of the second fuel decreases.

  The low calorific value LCV of the second fuel may be calculated based on the measurement of one parameter or multiple parameters when the fuel is stored in a fuel source such as a fuel storage tank. By obtaining a measure for the low heating value in this way, the low heating value can be stored in the control unit and used automatically for control of the internal combustion engine. Many different parameters can be measured in a manner known per se to provide a calculation of the low calorific value of the fuel. It is also possible to use this information to measure one or more operating parameters of the engine and to determine the setting of the fuel component being mixed into the second fuel. Such operating parameters can include, for example, measurement of changes in pressure through a cycle within at least one cylinder. Alternatively, the low heating value that can be used may be set manually in the control system of the internal combustion engine.

  An increase in cylinder charge mixing to the actual combustion zone is achieved, which compensates for the reduced oxygen content of the cylinder charge caused by an increased degree of exhaust gas recirculation, thus increasing exhaust gas recirculation. The combustion conditions in between are improved with a larger volume of injected fuel with respect to the calorific value of the injected fuel.

The details of the various embodiments described above can be combined with further embodiments within the scope of the claims.
The matters described in the claims at the beginning of the application are appended as they are.
[1] A cylinder having a reciprocating piston in each interior and having a combustion chamber above the piston, and at least one fuel injection for directly injecting fuel into the combustion chamber above the piston during operation And operating the internal combustion engine with a calibrator, wherein the engine is operated in an exhaust gas recirculation and is sometimes operated in an environment of a first emission standard that limits the emission of pollutant components along with the exhaust gas, In a method operated at different times in another environment with a second, more stringent emission standard that limits the emission of such pollutants along with exhaust gases,
a) When operating in the environment having the first emission standard, the engine is operated with a first fuel having a first low heating value and with a first degree of exhaust gas recirculation. And
b) when operating in another environment having the second more stringent emission standard, the engine is a second fuel having a second low heat value lower than the first low heat value; and Being operated at a second degree of exhaust gas recirculation higher than the first degree of exhaust gas recirculation;
For a given engine load, fuel injection is faster when the internal combustion engine is operating with the second fuel than when the internal combustion engine is operating with the first fuel. Start with the timing
A method characterized by.
[2] The method according to [1], wherein the second low calorific value of the second fuel is less than 90% of the first low calorific value of the first fuel. .
[3] The mixture including the second fuel as the first component and at least one other component having a low calorific value lower than the low calorific value of the first fuel. The method according to [1] or [2], wherein
[4] The method according to any one of [1] to [3], wherein the second fuel includes an incombustible component.
[5] The change from the first fuel to the second fuel is gradually performed during operation of the engine, according to any one of [1] to [4] Method.
[6] The first fuel includes a liquid fuel, and the second fuel includes a distillate fuel emulsified with water, a residual fuel emulsified with water, alcohol, ammonia, dimethyl ether, and a mixture thereof. The method according to any one of [1] to [5], comprising a fuel selected from the group.
[7] The first fuel comprises a fuel gas, and the second fuel is selected from the group comprising a low heating value boil-off gas, a synthesis gas, a gas mixed with an inert gas, and a mixture thereof. The method according to any one of [1] to [5], characterized by comprising a gaseous fuel.
[8] The method according to any one of [1] to [7], wherein the internal combustion engine is a low-speed two-stroke crosshead diesel internal combustion engine.
[9] The method according to any one of [1] to [8], wherein the internal combustion engine is a medium-speed four-stroke internal combustion engine.
[10] For a given engine load, the fuel injection occurs when the internal combustion engine is operating with the second fuel rather than the internal combustion engine is operating with the first fuel. The method according to any one of [1] to [9], wherein the method is performed while the engine cycle rate is larger.
[11] The internal combustion engine is a fixed engine located at a specific earth position, and the engine is sometimes operating in an environment of a first emission standard, Therefore, the method according to any one of [1] to [10], wherein the operation is performed at different times in the different environment of the second stricter emission standard.
[12] A cylinder having a reciprocating piston in each interior and having a combustion chamber above the piston, and at least one fuel injection for directly injecting fuel into the combustion chamber above the piston during operation Engine, at least one turbocharger, an exhaust gas recirculation pipe, a control valve, and an exhaust gas recirculation blower for sending the recirculated exhaust gas to the inflow air pipe of the internal combustion engine The internal combustion engine control unit is configured to control the internal combustion engine according to the method according to any one of [1] to [11].

Claims (12)

A cylinder having a reciprocating piston in each interior and having a combustion chamber above the piston; and at least one fuel injector for injecting fuel directly into the combustion chamber above the piston during operation. a method of operating an internal combustion engine wherein the internal combustion engine is in an environment where first emission standards that limit the emission of contaminant together with the exhaust gas is applied, the first having a first low heat value In another environment where a second, more stringent emission standard is applied that is operated with fuel and limits the emission of such pollutants along with exhaust gas, it is operated with a second fuel having a second low heating value. In the method
When operating in an environment where a) the first emission standards are applied, the internal combustion engine, comprising: operating at an exhaust gas recirculation of the first degree,
b) when operating in another environment where the second, more stringent emission criteria are applied , the internal combustion engine is configured to increase the mixing of cylinder filling into the actual combustion region in the combustion chamber. of being operated in the second fuel having a second low heating value lower than the low heating value, and the internal combustion engine is re-exhaust gas higher second degree of the exhaust gas recirculation of the first degree Being driven in circulation,
For a given engine load, fuel injection may occur in the engine cycle when the internal combustion engine is operating with the second fuel than when the internal combustion engine is operating with the first fuel . Starting earlier ,
A method characterized by.   The method of claim 1, wherein the second low heat value of the second fuel is less than 90% of the first low heat value of the first fuel. Said second fuel is characterized in that said first fuel as a first component, a mixture comprising at least one other component having a low have calorific than calorific of the first fuel The method according to claim 1 or 2.   4. A method according to any one of claims 1 to 3, characterized in that the second fuel comprises an incombustible component. 5. A method according to any one of the preceding claims, characterized in that the change from the first fuel to the second fuel is carried out gradually during operation of the internal combustion engine.   The first fuel comprises a liquid fuel, and the second fuel is selected from the group comprising distillate fuel emulsified with water, residual fuel emulsified with water, alcohol, ammonia, dimethyl ether, and mixtures thereof. 6. A method according to any one of the preceding claims, characterized in that it comprises a fuel to be used.   The first fuel comprises a fuel gas, and the second fuel is a gaseous state selected from the group comprising a low heating value boil-off gas, a synthesis gas, a gas mixed with an inert gas, and mixtures thereof. 6. A method according to any one of the preceding claims, characterized in that it comprises a fuel.   The method according to claim 1, wherein the internal combustion engine is a low-speed two-stroke crosshead diesel internal combustion engine.   The method according to claim 1, wherein the internal combustion engine is a medium-speed four-stroke internal combustion engine. For a given engine load, the fuel injection occurs when the internal combustion engine is operating with the second fuel rather than when the internal combustion engine is operating with the first fuel . 10. Method according to any one of claims 1 to 9, characterized in that it is carried out during a large proportion in the engine cycle .   The internal combustion engine is a fixed engine located at a particular earth location, and the engine is sometimes operating in a first emission standard environment and due to current weather conditions, 11. The method according to any one of claims 1 to 10, characterized in that it is operating at different times in the different environment with two more stringent emission standards.   A cylinder with a reciprocating piston in each interior and a combustion chamber above the piston, and at least one fuel injector that injects fuel directly into the combustion chamber above the piston during operation; An internal combustion engine comprising at least one turbocharger, an exhaust gas recirculation pipe, a control valve, and an exhaust gas recirculation blower for sending the recirculated exhaust gas to an inflow air pipe of the internal combustion engine An internal combustion engine, wherein the control unit of the internal combustion engine is configured to control the internal combustion engine according to the method of any one of claims 1 to 11.

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