KR102164426B1 - Internal combustion engine - Google Patents

Abstract

The present invention is a two-stroke crosshead diesel internal combustion engine having a plurality of cylinders, and is a two-stroke crosshead diesel internal combustion engine configured to inject a main fuel and an auxiliary fuel to each of the plurality of cylinders. The main fuel includes fuel oil and water. The auxiliary fuel includes fuel oil. The two-stroke crosshead diesel internal combustion engine is configured to ignite the combination of the main fuel and the auxiliary fuel by the high temperature achieved when the gas in the cylinder is compressed, and the mass percentage of water in the main fuel is at least 30%, and the The mass percentage of fuel oil is higher than that of fuel oil in the main fuel.

Description

Internal combustion engine {INTERNAL COMBUSTION ENGINE}

The present invention relates to an internal combustion engine and an internal combustion engine system.

Two-stroke internal combustion engines are used as propulsion engines in ships such as container ships, bulk cargo ships and oil tankers. It has become increasingly important to reduce unwanted emissions from internal combustion engines. Particular attention has been paid to the reduction of NOx.

The International Maritime Organization (IMO), a specialized organization of the United Nations, has set emission standards in a range known as Tier I, Tier II, and Tier III, with Tier I and Tier II emission standards globally. In effect, Tier III emission standards apply to the NOx Emission Control Area (ECA). Tier II and Tier III NOx emission standards are in effect for newer institutions, while Tier I NOx requirements are for existing institutions manufactured before 2000.

One way to reduce NOx emissions is to use a selective catalytic reduction (SCR) system. SCR systems take in the exhaust gas and convert NOx into less harmful substances. Another way to reduce NOx emissions is an exhaust gas recirculation (EGR) system that operates by reducing the NOx produced in the engine by lowering the oxygen concentration and flame temperature by recirculating a portion of the exhaust gas back to the engine cylinder. However, EGR systems and SCR systems are complex and expensive to install and maintain.

An alternative way to reduce NOx emissions is to mix water into the fuel oil used by internal combustion engines. Water reduces the amount of NOx in the exhaust gas by lowering the combustion temperature.

However, mixing water with the fuel increases the ignition delay, which can cause an excessively large amount of fuel to mix with the surrounding air before ignition. When finally ignition occurs, a pressure wave similar to an explosion can form inside the cylinder. This can be observed in pressure tracking and through acoustic (listening), and is commonly referred to as diesel knocking. This can lead to serious damage to the combustion chamber components. Also, if the water level is very high, the ignition delay can be increased to the extent that ignition does not occur at all, which can cause complete or partial misfire of the injected fuel.

Therefore, there remains a problem of simply and effectively reducing NOx emissions in an internal combustion engine.

According to a first aspect, the present invention is a two-stroke crosshead diesel internal combustion engine having a plurality of cylinders, wherein the main fuel including fuel oil and water and the auxiliary fuel including fuel oil are injected into each of the plurality of cylinders. And is configured to ignite the combination of the main fuel and the sub-fuel by the high temperature achieved when the gas in the cylinder is compressed,

● The mass percentage of water in the main fuel is at least 30%,

● The mass percentage of fuel oil in the auxiliary fuel is higher than that of the fuel oil in the main fuel,

It relates to a two-stroke crosshead diesel internal combustion engine.

As a result, more water can be added to the main fuel without diesel knocking or misfire by using an auxiliary fuel having a fuel oil percentage higher than the mass percentage of the fuel oil in the main fuel. This allows for significant reduction of NOx from exhaust gases in a simple and effective manner that allows compliance with Tier III requirements without the use of EGR systems and/or SCR systems.

The internal combustion engine is preferably a two-stroke crosshead diesel internal combustion engine for propulsion of marine vessels with a power per cylinder of at least 400 kW. Examples of fuel oil include Marine Gas Oil (MGO), Marine Diesel Oil (MDO), Intermediate Fuel Oil (IFO), Marine Fuel Oil (MFO), and Heavy Fuel Oil (HFO). The fuel oil used as the main fuel and the fuel oil used as the auxiliary fuel may be the same type of fuel oil. Alternatively, the fuel oil used as the main fuel and the fuel oil used as the auxiliary fuel may be different. The amount of water in the main fuel can be so high that the mixture of water and fuel oil cannot self-ignite. The main fuel and the auxiliary fuel can be sequentially injected into the cylinders through a single fuel valve. Alternatively, the main fuel and auxiliary fuel can be injected into the cylinders through two fuel valves. Since the concentration of the fuel in the auxiliary fuel is higher, the auxiliary fuel is ignited before the main fuel, whereby the heat generated by the combustion of the auxiliary fuel ignites the main fuel. Therefore, the auxiliary fuel acts as the ignition fuel. The internal combustion engine may be configured to ignite the auxiliary fuel through compression ignition, whereby the flame of the auxiliary fuel ignites the main fuel.

In some embodiments, the mass percentage of water in the main fuel is at least 40%, at least 45% or at least 50%.

The mass percentage of water in the main fuel is obtained by the following equation.

는 주연료 중의 물의 질량백분율이고,

는 주연료 중의 물의 질량이고,

는 주연료의 총질량이다.here,

Is the mass percentage of water in the main fuel,

Is the mass of water in the main fuel,

Is the total mass of the main fuel.

The main fuel preferably consists mainly of water and fuel oil.

In some embodiments, the mass percentage of fuel oil in the auxiliary fuel is at least 50%, at least 75%, at least 90%, at least 95%, or at least 99%.

The mass percentage of fuel oil in the auxiliary fuel is obtained by the following equation.

는 부연료 중의 연료유의 질량백분율이고,

는 부연료 중의 연료유의 질량이고,

는 부연료의 총질량이다.here,

Is the mass percentage of fuel oil in the auxiliary fuel,

Is the mass of fuel oil in the auxiliary fuel,

Is the total mass of the auxiliary fuel.

In some embodiments, the mass percentage of subfuel of the total fuel injected into the multiple cylinders is less than 10%, 7%, 5%, 3%, or 1%.

By limiting the amount of auxiliary fuel used, the amount of NOx emitted can be further reduced.

The mass percentage of the auxiliary fuel among the total fuel injected through multiple cylinders is obtained by the following equation.

는 다수의 실린더로 분사되는 전체 연료 중 부연료의 질량백분율이고,

는 다수의 실린더로 분사되는 부연료의 질량이고,

는 다수의 실린더로 분사되는 전체연료의 총질량이다.here,

Is the mass percentage of the auxiliary fuel among the total fuel injected through multiple cylinders,

Is the mass of the auxiliary fuel injected into multiple cylinders,

Is the total mass of fuel injected into multiple cylinders.

In some embodiments, the mass percentage of the main fuel of the total fuel injected into the multiple cylinders is at least 90%, 93%, 95%, 97%, or 99%.

The mass percentage of the main fuel among the total fuel injected through multiple cylinders is obtained by the following equation.

는 다수의 실린더로 분사되는 전체 연료 중 주연료의 질량백분율이고,

는 다수의 실린더로 분사되는 주연료의 질량이고,

는 다수의 실린더로 분사되는 전체 연료의 총질량이다.here,

Is the mass percentage of the main fuel among the total fuel injected through multiple cylinders,

Is the mass of the main fuel injected into multiple cylinders,

Is the total mass of fuel injected into multiple cylinders.

If the engine operates on only the main fuel and the auxiliary fuel, the mass percentage of the main fuel plus the mass percentage of the auxiliary fuel will always be 100%.

In some embodiments, the mixture of fuel oil and water in the main fuel is emulsified prior to delivery to the multiple cylinders.

As a result, by using an emulsified main fuel and an auxiliary fuel, which is preferably made of pure fuel oil, a heterogeneous mixture of water and fuel oil is formed in the cylinders. This causes the amount of water in the main fuel to increase because the fuel oil in the secondary fuel will ignite the heterogeneous mixture.

Surfactants may be added to the main fuel or water to ensure that the main fuel is properly emulsified with water.

In some embodiments, each cylinder includes a first fuel valve and a second fuel valve, and the internal combustion engine is configured to inject the main fuel through the first fuel valve and the auxiliary fuel through the second fuel valve. .

In some embodiments, the internal combustion engine has a first mode and a second mode, wherein the internal combustion engine is configured to inject main fuel and auxiliary fuel into each of a plurality of cylinders in a first mode, and a plurality of cylinders in the second mode. Each is configured to inject an alternative main fuel including fuel oil, the fuel oil of the main fuel being a fuel oil of the first type and the fuel oil of the alternative main fuel being of a second type different from the fuel oil of the first type. It is fuel oil, and the fuel oil of the auxiliary fuel is a first type of fuel oil or a second type of fuel oil.

As a result, by using fuel oil of the type already used by the engine as an auxiliary fuel, there is no need to provide a separate fuel tank for the auxiliary fuel.

The internal combustion engine can also be configured to use an auxiliary fuel in the second mode. The first type of fuel oil is HFO and the second type of fuel oil may be a lighter fuel oil such as MGO or MDO. This allows the agency to operate as HFO in areas with no sulfur emission regulation and as MGO or MDO in areas with sulfur emission regulation.

According to a second aspect, the present invention is an internal combustion engine system comprising a first fuel tank for storing a first type of fuel oil, a water supply system, and a two-stroke crosshead diesel internal combustion engine having a plurality of cylinders. The engine is in fluid connection with the first fuel tank and the water supply system, and the internal combustion engine includes fuel oil and main fuel including water provided from the first type of fuel oil and water supply system to each of the plurality of cylinders. It is configured to inject fuel and is configured to ignite the combination of the main fuel and the sub-fuel by the high temperature achieved when the gas in the cylinder is compressed by the internal combustion engine,

● The mass percentage of water in the main fuel is at least 30%,

● The mass percentage of fuel oil in the auxiliary fuel is higher than that of the fuel oil in the main fuel,

It relates to an internal combustion engine system.

The internal combustion engine is preferably a two-stroke crosshead diesel internal combustion engine for propulsion of marine vessels with a power per cylinder of at least 400 kW.

In some embodiments, the mass percentage of water in the main fuel is at least 40%, at least 45% or at least 50%.

In some embodiments, the mass percentage of fuel oil in the auxiliary fuel is at least 50%, at least 75%, at least 90%, at least 95%, or at least 99%.

In some embodiments, the mass percentage of subfuel of the total fuel injected into the multiple cylinders is less than 10%, 7%, 5%, 3%, or 1%.

In some embodiments, the mass percentage of the main fuel of the total fuel injected into the multiple cylinders is at least 90%, 93%, 95%, 97%, or 99%.

In some embodiments, the system further comprises an emulsification system having a first inlet, a second inlet and a first outlet, the first inlet being in fluid communication with the first fuel tank and the second inlet being in fluid communication with the water supply system. And the first outlet is in fluid communication with the internal combustion engine, and the emulsification system is configured to generate the main fuel by creating an emulsified mixture of water and a first type of fuel oil.

The emulsifying system can produce an emulsified mixture by adding a surfactant.

In some embodiments, the fuel oil of the auxiliary fuel is a first type of fuel oil, the first fuel tank is directly fluidly connected to the internal combustion engine to provide the auxiliary fuel to the internal combustion engine, and indirectly through an emulsification system to the internal combustion engine. It is fluidly connected to provide the main fuel to the internal combustion engine.

As a result, a single fuel tank can be used to provide both main and secondary fuels.

In some embodiments, each cylinder includes a first fuel valve and a second fuel valve, and the internal combustion engine is configured to inject the main fuel through the first fuel valve and the auxiliary fuel through the second fuel valve. .

In some embodiments, the system may further include a second fuel tank for storing a second type of fuel oil, the second fuel tank in fluid connection with the internal combustion engine, and the internal combustion engine in a first mode and a second A mode, wherein the first mode is configured to inject main fuel and sub-fuel to each of the plurality of cylinders, and in the second mode to inject an alternative main fuel including a second type of fuel oil to each of the plurality of cylinders. And the fuel oil of the auxiliary fuel is a first type of fuel oil or a second type of fuel oil.

Different aspects of the present invention may be practiced in different ways, including the internal combustion engines and internal combustion engine systems described above and also below, each of which produces one or more of the advantages described above, and the aspects Each has one or more preferred embodiments corresponding to the preferred embodiments described above and/or in connection with at least one of the aspects recited in the dependent claims. In addition, it will be appreciated that embodiments described in connection with one of the aspects described herein can be equally applied to other aspects.

The above-described and/or other objects, features, and advantages of the present invention will be better understood by reading the following illustrative and non-limiting detailed description of embodiments of the present invention with reference to the accompanying drawings.
1 is a diagram schematically showing an internal combustion engine system according to an embodiment of the present invention.

In the following description, reference is made to the accompanying drawings, which exemplarily show how the present invention may be practiced.

1 is a diagram schematically showing an internal combustion engine system 100 for propulsion of a marine vessel according to an embodiment of the present invention. The internal combustion engine system 100 includes a first fuel tank 103 for storing a first type of fuel oil, such as heavy fuel oil or gas oil, a water supply system 104, an emulsification system 105. ) And an internal combustion engine 101 having four cylinders 102. In other embodiments, the internal combustion engine 101 may comprise a different number of cylinders, such as 2 cylinders, 6 cylinders, 8 cylinders, 10 cylinders or 12 cylinders. The water supply system 104 may be configured to generate purified water, for example from sea water, and/or may include a water tank containing the purified water. The emulsification system 105 includes a first inlet 108 in fluid connection with the first fuel tank 103, a second inlet 109 in fluid connection with the water supply system 104, and a fluid connection with the internal combustion engine 101. It has a first outlet (110). The emulsification system 105 is configured to produce an emulsified mixture of water and fuel oil of a first type, wherein the mass percentage of water is at least 30%. The emulsifying system 105 may be configured to add a surfactant to the mixture to ensure that the water and fuel oil are properly emulsified. The first fuel tank 103 is directly fluidly connected to the internal combustion engine 101 to provide an auxiliary fuel composed of a first type of fuel oil. Accordingly, the first fuel tank 103 is indirectly fluidly connected to the internal combustion engine (via the emulsification system 105) and also directly fluidly connected. Each cylinder 102 includes a first fuel valve 106 and a second fuel valve 107, and the internal combustion engine injects the main fuel through the first fuel valve 106 and supplies the auxiliary fuel to the second fuel valve. It is configured to spray through 107. Each cylinder may include two or more fuel valves, for example, a total of four fuel valves, in which case two fuel valves are used for the main fuel and two fuel valves are used for the auxiliary fuel. The internal combustion engine 101 is configured to ignite the combination of the main fuel and the sub-fuel by the high temperature achieved when the gas in the cylinders 102 is compressed. The mass percentage of the auxiliary fuel among the total fuel injected into the plurality of cylinders is preferably small, for example less than 10%, 7%, 5% or 3%. As a result, the mass percentage of the main fuel in the total fuel injected into the plurality of cylinders is preferably high, for example at least 90%, 93%, 95% or 97%. Accordingly, the auxiliary fuel acts as an ignition fuel that ignites the combination of the main fuel and the auxiliary fuel. As a result, a non-homogeneous mixture of water and fuel oil of the first type is formed in the cylinder by using an emulsified main fuel containing fuel of the first type and an auxiliary fuel composed of only fuel oil of the first type. This causes the amount of water in the main fuel to increase because the fuel oil in the secondary fuel will ignite the heterogeneous mixture.

The internal combustion engine system may optionally further include a second fuel tank 111 for storing a second type of oil, and the second fuel tank 111 is fluidly connected to the internal combustion engine 101, the internal combustion engine ( 101) has a first mode and a second mode, and the internal combustion engine 101 is configured to inject main fuel and auxiliary fuel to each of the cylinders 102 in the first mode, and the cylinders 102 in the second mode. Each is configured to inject an alternative main fuel comprising a second type of fuel oil. The second fuel tank 111 may be indirectly connected to the internal combustion engine 101 through the emulsification system 105, whereby the alternative main fuel is a mixture of water and a second type of fuel oil emulsified, e.g., a mass percentage of water. It is an emulsified mixture that is at least 30%. Thus, the internal combustion engine 101 can also use the auxiliary fuel in the second mode. Alternatively, the second fuel tank 111 may be directly connected to the internal combustion engine 101, thereby eliminating the need for auxiliary fuel in the second mode. In some embodiments (not shown in the drawing), the second fuel tank 111 is directly connected to the internal combustion engine 102 to provide auxiliary fuel to the second fuel valve 107 in the first mode, and the second mode Is provided to the first fuel valve 106, in which case both the auxiliary fuel and the alternative main fuel are made of a second type of fuel oil. The first type of fuel oil may be HFO, and the second type of fuel oil may be a lighter fuel oil such as MGO or MDO.

Although some embodiments have been described and illustrated in detail, the present invention is not limited to these embodiments, and may be implemented in other ways within the scope of the gist of the present invention defined by the claims below. In particular, it should be understood that other embodiments may be used and structural and functional modifications may be made without departing from the scope of the present invention.

In the device claims enumerating multiple means, many of these means may be embodied in one and the same hardware item. The fact that specific measures are recited in different dependent claims or described in different embodiments does not indicate that a combination of these measures cannot be used to advantage.

The term "comprising/comprising", as used herein, specifies the presence or addition of features, integers, steps or components to which it is mentioned, but not the presence or addition of one or more other features, integers, steps, components or groups thereof. It is emphasized that it should be considered not to be excluded.

Claims (10)

An internal combustion engine having a plurality of cylinders,
It is configured to inject the main fuel including fuel oil and water and the auxiliary fuel including fuel oil into each of the plurality of cylinders, and the combination of the main fuel and the auxiliary fuel is ignited by the high temperature achieved when the gas in the cylinder is compressed. In the internal combustion engine configured to let,
The internal combustion engine is a two-stroke crosshead internal combustion engine, and the mass percentage of the main fuel among the total fuel injected into the plurality of cylinders is at least 90%,
The amount of fuel oil in the auxiliary fuel is large enough to allow the auxiliary fuel to self-ignite by the high temperature achieved when the gas in the cylinder is compressed, and the amount of water in the main fuel is so large that the main fuel cannot self-ignite. The amount of fuel oil in the fuel is large enough to allow the flame generated from the secondary fuel to ignite the main fuel,
The internal combustion engine, characterized in that the internal combustion engine is configured to ignite the auxiliary fuel through compression ignition, whereby a flame generated from ignition of the auxiliary fuel ignites the main fuel. The method according to claim 1,
An internal combustion engine, characterized in that the mass percentage of fuel oil in the auxiliary fuel is any one of 50% or more, 75% or more, 90% or more, 95% or more, and 99% or more. The method according to claim 1 or 2,
An internal combustion engine, characterized in that a mixture of water and fuel oil in the main fuel is emulsified before being delivered to a plurality of cylinders. The method according to claim 1,
An internal combustion engine, characterized in that each cylinder includes a first fuel valve and a second fuel valve, and the internal combustion engine is configured to inject the main fuel through the first fuel valve and the secondary fuel through the second fuel valve. . The method according to claim 1,
The internal combustion engine has a first mode and a second mode, and is configured to inject main fuel and sub-fuel into each of the plurality of cylinders in the first mode, and in the second mode, an alternative main fuel comprising fuel oil in each of the plurality of cylinders. It is configured to inject fuel, the fuel oil of the main fuel is fuel oil of the first type, the fuel oil of the alternative main fuel is the fuel oil of the second type different from the fuel oil of the first type, and the fuel oil of the auxiliary fuel is An internal combustion engine, characterized in that it is a first type of fuel oil or a second type of fuel oil. An internal combustion engine system comprising an internal combustion engine having a first fuel tank, a water supply system and a plurality of cylinders for storing a first type of fuel oil,
An internal combustion engine is fluidly connected to a first fuel tank and a water supply system, and the internal combustion engine system comprises fuel oil and a main fuel comprising a first type of fuel oil and water provided from the water supply system to each of the plurality of cylinders. An internal combustion engine system configured to inject a secondary fuel, wherein the two-stroke crosshead diesel internal combustion engine is configured to ignite a combination of the main fuel and the secondary fuel by the high temperature achieved when the gas in the cylinder is compressed,
The internal combustion engine is a two-stroke crosshead diesel internal combustion engine, and the mass percentage of the main fuel among the total fuel injected into the plurality of cylinders is at least 90%,
The amount of fuel oil in the auxiliary fuel is large enough to allow the auxiliary fuel to self-ignite by the high temperature achieved when the gas in the cylinder is compressed, and the amount of water in the main fuel is so large that the main fuel cannot self-ignite. The amount of fuel oil in the fuel is large enough to allow the flame generated from the secondary fuel to ignite the main fuel,
The internal combustion engine system, characterized in that the internal combustion engine is configured to ignite the auxiliary fuel through compression ignition, whereby a flame generated from ignition of the auxiliary fuel ignites the main fuel. The method of claim 6,
An internal combustion engine system, characterized in that the mass percentage of fuel oil in the auxiliary fuel is any one of 50% or more, 75% or more, 90% or more, 95% or more, and 99% or more. The method according to claim 6 or 7,
The system further comprises an emulsification system having a first inlet, a second inlet and a first outlet, wherein the first inlet is in fluid connection with the first fuel tank and the second inlet is in fluid connection with the water supply system and the first outlet An internal combustion engine system in fluid connection with a two-stroke crosshead diesel internal combustion engine, wherein the emulsification system is configured to generate main fuel by creating an emulsified mixture of water and fuel oil of the first type. The method of claim 6,
The fuel oil of the auxiliary fuel is the first type of fuel oil, and the first fuel tank is directly fluidly connected to the two-stroke crosshead diesel internal combustion engine to provide the auxiliary fuel to the two-stroke crosshead diesel internal combustion engine. An internal combustion engine system, characterized in that indirectly fluidly connected to the engine through an emulsification system to supply main fuel to a two-stroke crosshead diesel internal combustion engine. The method of claim 6,
The system further comprises a second fuel tank for storing a second type of fuel oil, the second fuel tank being fluidly connected to the two-stroke crosshead diesel internal combustion engine, and the two-stroke crosshead diesel internal combustion engine with the first mode and A second mode is provided, wherein the first mode is configured to inject the main fuel and the sub-fuel into each of the plurality of cylinders, and in the second mode to inject an alternative main fuel comprising a second type of fuel oil into each of the plurality of cylinders. Wherein the fuel oil of the auxiliary fuel is a first type of fuel oil or a second type of fuel oil.

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