KR102382129B1 - Diesel engine for ship - Google Patents

Abstract

(Challenge) Reducing the combustion residues that can be produced in fossil fuels or alternative fuels.
(Solution Means) The marine diesel engine 1 has a fuel injection valve 30 having an injection port 31 for injecting fossil fuels and alternative fuels, and toward the fuel injection valve 30, The fuel pump 41 which pressurizes the 1st fuel which consists of one, the fuel path L from the fuel pump 41 to the injection port 31, and predetermined positions P1 and P2 in the fuel path L. ), injection systems 50 and 60 for injecting the second fuel composed of the other of the fossil fuel and the alternative fuel, and a control unit 92 for controlling the injection systems 50 and 60 are provided. The fuel injection valve 30 injects the first fuel and the second fuel in a layered manner. The control unit 92 controls the injection systems 50 and 60 so that both the fuel layers F1, F2, F3 composed of the first fuel and the fuel layers A1 and A2 composed of the second fuel are two or more layers. to control

Description

Marine diesel engine {DIESEL ENGINE FOR SHIP}

The technology disclosed herein relates to a marine diesel engine.

As a method for reducing nitrogen oxides (NOx) contained in exhaust gas of a marine diesel engine, injecting a plurality of types of fuel from one fuel injection valve is widely known.

For example, in the dual fuel injection system disclosed in Patent Document 1, it is disclosed that a pilot fuel for ignition composed of fossil fuels such as heavy oil or light oil A and a main fuel composed of methanol as an alternative fuel are injected in layers. there is.

The injection system disclosed in the said patent document 1 can inject the pilot fuel for ignition with respect to the main fuel in a fuel injection valve, and can inject the fuel which became layered in order of the pilot fuel for ignition and a main fuel into a combustion chamber. According to the same document, the injection amount of the pilot fuel for ignition is increased in the case of unstable ignition, and decreased in the case of stable ignition.

Japanese Patent Application Laid-Open No. 6-159182

By the way, in the structure described in the said patent document 1, among the fuel layers injected into a combustion chamber, the fuel layer which consists of a main fuel and the fuel layer which consists of pilot fuel for ignition both become one layer.

In this case, although combustion is accelerated|stimulated by pilot combustion for ignition, the main fuel injected following the pilot fuel for ignition, the inventors of this application realized that combustion residues may arise in the main fuel.

That is, the injection amount of the main fuel is increased or decreased according to the load of the engine or the like. Even if the injection amount of the pilot fuel for ignition is increased, if the main fuel injected following it is not reduced, there is a possibility that a combustion residue will be generated in the main fuel.

Here, the case where a fossil fuel is used as the pilot fuel for ignition and an alternative fuel is used as the main fuel has been described as an example. However, the above-mentioned problem is that the alternative fuel is used as the pilot fuel for ignition and the fossil fuel is used as the main fuel. It is common even when used. Depending on the composition of the alternative fuel, since it can also be used as a pilot fuel for ignition, the problem of combustion residues of the main fuel which consists of fossil fuels may arise.

The technology disclosed herein has been made in view of such a point, and its object is to reduce combustion residues that may occur in fossil fuels or alternative fuels.

The technology disclosed herein relates to a marine diesel engine. This marine diesel engine includes: a cylinder partitioning a combustion chamber; a fuel injection valve formed to face the combustion chamber and having an injection port for injecting fossil fuels and alternative fuels; A fuel pump for pressurizing a first fuel composed of one of the fuel, a fuel path from the fuel pump to the injection port, and a second position composed of the other of the fossil fuel and the alternative fuel at a predetermined position in the fuel path an injection system for injecting fuel, and a control unit for controlling the injection system, wherein the fuel injection valve is configured to inject the first fuel pumped by the fuel pump and the second fuel injected by the injection system. In a state in which they are alternately arranged, spray in layers.

Then, the control unit controls the injection system such that, among the fuel layers injected from the fuel injection valve, both the fuel layer composed of the first fuel and the fuel layer composed of the second fuel are two or more layers. .

Here, "fossil fuel" refers to a general fuel that can be refined from crude oil, such as diesel fuel, effluent oil, and residual oil. On the other hand, "alternative fuel" is a fuel that can replace natural petroleum (Alternative Fuel), and refers to general fuels that can replace petroleum, such as ammonia, biofuel, methanol, and ethanol.

According to this configuration, the injection system injects the second fuel into the fuel path through which the first fuel flows. By injecting the second fuel into the fuel path, for example, the first fuel, the second fuel, and the first fuel are sequentially injected from the fuel injection valve in layers.

In this case, while one of the 1st and 2nd fuel burns as a main fuel which produces|generates power for driving a marine diesel engine, the other of 1st and 2nd fuel is a pilot for igniting a main fuel. function as fuel. Here, the control unit controls the injection system so that both the fuel layer made of the first fuel and the fuel layer made of the second fuel are two or more layers.

By controlling in this way, for example, the first fuel, the second fuel, the first fuel, the second fuel, and the first fuel are sequentially injected from the fuel injection valve in a layered manner. Here, when it is assumed that the 1st fuel functions as a main fuel and the 2nd fuel functions as an assist fuel, the 1st fuel injected following the 1st 2nd fuel is the 1st 2nd fuel. It is divided into two parts, one in which combustion is accelerated by this and one in which combustion is accelerated by the second secondary fuel injected after that. While the first fuel to be promoted is divided into two, the combustion of each of the first fuels divided into two can be promoted by the second fuel divided into two in the same manner as the first fuel. As a result, combustion of the 1st fuel as a main fuel is accelerated|stimulated more reliably, and it becomes possible to suppress generation|occurrence|production of a combustion residue.

Such a behavior is the same when a 1st fuel functions as an assist fuel, and also when a 2nd fuel functions as a main fuel. In that case, as for the second fuel injected following the first first fuel, combustion is promoted by the first first fuel, and combustion is promoted by the second first fuel injected after that. It will be 2 minutes. Thereby, combustion of the 2nd fuel as a main fuel is accelerated|stimulated more reliably, and it becomes possible to suppress generation|occurrence|production of a combustion residue.

In addition, the injection system includes a first injection system for injecting the second fuel into a predetermined first injection position in the fuel path, and a second injection system on an upstream side of the first injection position in the fuel path. a second injection system for injecting the second fuel into a position, wherein the fuel injection valve includes: the first fuel pumped by the fuel pump; the second fuel injected by the first injection system; The first fuel pumped by a fuel pump, the second fuel injected by the second injection system, and the first fuel pumped by pressure by the fuel pump in a sequential order of a layered liquid containing a fuel layer in the combustion chamber It is good also as spraying inside.

According to this configuration, combustion of the first fuel is promoted more reliably, and it is advantageous in suppressing generation of combustion residues.

In addition, the control unit, according to the load of the marine diesel engine, so that the injection period by the first injection system and at least a part of the injection period by the second injection system overlap, the first injection system is the first injection system It is good also as controlling the timing at which injection of secondary fuel starts, and the timing at which the said 2nd injection system starts injection of the said 2nd fuel.

According to this configuration, the amount of the second fuel injected by the first injection system and the amount of the first fuel sandwiched by the second fuel injected by the second injection system can be adjusted according to the engine load. . Thereby, it becomes possible to ensure the performance of the marine diesel engine.

Further, the control unit is located between a fuel layer made of the second fuel injected by the first injection system and a fuel layer made of the second fuel injected by the second injection system, and the first Timing at which the first injection system starts injecting the second fuel so that the amount of the fuel layer made of fuel becomes a constant ratio with respect to the injection amount per one time of the first fuel; It is good also as controlling the timing of starting injection of the 2nd fuel.

According to this structure, when ensuring the performance of the diesel engine for ships, it becomes advantageous.

Moreover, while calculating a predetermined waiting time based on the load of the said marine diesel engine, the said control part determines the timing at which the said 1st injection system starts injection of the said 2nd fuel by the minute of the calculated waiting time. , it is good also as delaying the timing at which the said 2nd injection system starts injection of the said 2nd fuel.

According to this structure, when ensuring the performance of the diesel engine for ships, it becomes advantageous.

Moreover, while calculating a predetermined waiting time based on the load of the said marine diesel engine, the said control part determines the timing at which the said 2nd injection system starts injection of the said 2nd fuel by the calculated waiting time. , may be delayed from the timing at which the first injection system starts injection of the second fuel.

According to this structure, when ensuring the performance of the diesel engine for ships, it becomes advantageous.

In addition, the control unit, regardless of the load of the marine diesel engine, the ratio of the injection amount of the second fuel by the first injection system to the injection amount of the second fuel by the second injection system is constant, It is good also as controlling the said 1st injection system and the said 2nd injection system.

According to this structure, when ensuring the performance of the diesel engine for ships, it becomes advantageous.

As described above, according to the marine diesel engine, it is possible to reduce combustion residues that may be generated in fossil fuels or alternative fuels.

1 is a schematic diagram illustrating a configuration of a marine diesel engine.
2 is a schematic diagram illustrating a configuration of a fuel injection device.
3 is a longitudinal sectional view illustrating a combustion chamber of a marine diesel engine.
4 is a diagram illustrating a layered liquid in a fuel path.
5 is a diagram illustrating a timing for injecting the second fuel.
6 : is a figure for demonstrating the quantity of 1st fuel.
7 is a diagram for explaining an injection amount according to an engine load.
Fig. 8 is a diagram corresponding to Fig. 5 in the first modification of the marine diesel engine.
Fig. 9 is a diagram corresponding to Fig. 6 in the first modification of the marine diesel engine.
It is a figure corresponding to FIG. 2 which shows the 2nd modification of the marine diesel engine.
It is a figure corresponding to FIG. 3 in the 2nd modification of the marine diesel engine.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this indication is described based on drawing. In addition, the following description is an example. 1 is a schematic diagram illustrating the configuration of a marine diesel engine (hereinafter, also simply referred to as "engine 1"). 2 is a schematic diagram illustrating the configuration of the fuel injection device 100 in the engine 1 , and FIG. 3 is a longitudinal sectional view illustrating the combustion chamber 17 of the engine 1 .

The engine 1 is an in-line multi-cylinder diesel engine provided with a plurality of cylinders 16 . This engine 1 is comprised as a 2-stroke 1-cycle engine which employ|adopted the uniflow scavenging method, and is mounted on large ships, such as a tanker, a container ship, and an automobile carrier.

An engine 1 mounted on a ship is used as a main engine for propelling the ship. That is, the output shaft of the engine 1 is connected to the propeller (not shown) of a ship via a propeller shaft (not shown). When the engine 1 drives, the output is transmitted to a propeller, and it is comprised so that a ship may be propelled.

In particular, the engine 1 according to the present disclosure is configured as a so-called crosshead type internal combustion engine in order to realize the longer stroke. That is, in this engine 1, the piston rod 22 which supports the piston 21 from below, and the connecting rod 24 connected to the crankshaft 23 are connected by the crosshead 25. As shown in FIG.

(1) Main composition

Hereinafter, the main part of the engine 1 is demonstrated.

As shown in FIG. 1 , the engine 1 includes a base 11 positioned below, a furniture 12 formed on the base 11 , and a cylinder formed on the furniture. A jacket 13 is provided. The base plate 11 , the furniture 12 , and the cylinder jacket 13 are fastened with a plurality of tie bolts and nuts extending in the vertical direction. The engine 1 also includes a cylinder 16 formed in the cylinder jacket 13, a piston 21 formed in the cylinder 16, and an output shaft rotating in association with the reciprocating motion of the piston 21 (for example, For example, a crankshaft 23) is provided.

The base plate 11 comprises the crankcase of the engine 1, and accommodates the crankshaft 23 and the bearing 26 which supports the crankshaft 23 so that it can rotate freely. The lower end of the connecting rod 24 is connected to the crankshaft 23 via a crank 27 .

The furniture 12 accommodates a pair of guide plates 28 , a connecting rod 24 , and a crosshead 25 . Among these, the pair of guide plates 28 are made of a pair of plate-shaped members formed along the piston axis direction, and are arranged at intervals in the width direction of the engine 1 (the left-right direction of the paper in FIG. 1 ). . The connecting rod 24 is arranged between the pair of guide plates 28 in a state where the lower end thereof is connected to the crankshaft 23 . The upper end of the connecting rod 24 is connected to the lower end of the piston rod 22 via a cross head 25 .

Concretely, the crosshead 25 is arrange|positioned between a pair of guide plate 28, and slides in an up-down direction along each guide plate 28. As shown in FIG. That is, the pair of guide plates 28 are comprised so that sliding of the crosshead 25 may be guided. The crosshead 25 is connected to the piston rod 22 and the connecting rod 24 via a crosshead pin 29 . The crosshead pin 29 is integrally connected to the piston rod 22 so as to move vertically, while the connecting rod 24 is rotated ( It is connected so as to make it move.

The cylinder jacket 13 is formed by arranging a cylinder liner 14 as an inner cylinder. Inside the cylinder liner 14, the aforementioned piston 21 is disposed. The piston 21 reciprocates in the vertical direction along the inner wall of the cylinder liner 14 . Moreover, the cylinder cover 15 is being fixed to the upper part of the cylinder liner 14. As shown in FIG. The cylinder cover 15 constitutes the cylinder 16 together with the cylinder liner 14 .

In addition, the cylinder cover 15 is provided with an exhaust valve 18 actuated by a copper valve device (not shown). The exhaust valve 18 partitions the combustion chamber 17 together with the cylinder 16 comprised by the cylinder liner 14 and the cylinder cover 15, and the front surface of the piston 21. As shown in FIG. The exhaust valve 18 opens and closes between the combustion chamber 17 and the exhaust pipe 19 . The exhaust pipe 19 has an exhaust port communicating with the combustion chamber 17 , and the exhaust valve 18 is configured to open and close the exhaust port.

Moreover, the fuel injection valve 30 for supplying fuel to the combustion chamber 17 is formed in the cylinder cover 15. As shown in FIG. As shown in FIG.2 and FIG.3, the fuel injection valve 30 is formed in the attitude|position facing the interior of the combustion chamber 17, and has the injection port 31 for injecting a fossil fuel and an alternative fuel.

Specifically, the fuel injection valve 30 is disposed in the combustion chamber 17 in a posture toward the injection port 31 , and includes a first fuel composed of one of fossil fuels and alternative fuels, and the other of fossil fuels and alternative fuels. In a state in which the formed second fuel is alternately arranged, it can be injected in layers.

Here, while one of the 1st and 2nd fuel functions as a main fuel which produces|generates the motive power of the engine 1, the other of the 1st and 2nd fuel functions as a pilot fuel for igniting the main fuel. will do Therefore, among the first and second fuels, at least one of the pressure and temperature leading to compression ignition is lower in the other functioning as the pilot fuel than in the one functioning as the main fuel.

In this embodiment, although the 1st fuel functions as a pilot fuel and the 2nd fuel functions as a main fuel, it takes as an example and demonstrates, but is not limited to this example. As shown in the second modification described later, the first fuel may function as the main fuel and the second fuel may function as the pilot fuel.

Moreover, in this embodiment, while using a fossil fuel as a 1st fuel, while taking as an example the pattern which uses an alternative fuel as a 2nd fuel, it demonstrates, but it is not limited to this example. As shown in the 2nd modified example mentioned later, while using an alternative fuel as a 1st fuel, you may use a fossil fuel as a 2nd fuel.

Specifically, as the first fuel according to the present embodiment, diesel fuel (so-called “diesel oil”) as a fossil fuel can be used, and as the second fuel according to the embodiment, ammonia as an alternative fuel is used. can be used That is, compared with the alternative fuel which concerns on the same embodiment, the fossil fuel which concerns on this embodiment is low in at least one of the pressure and temperature which reach compression ignition.

Although detailed later, the engine 1 which concerns on this embodiment injects the 2nd fuel into the fuel pump 41 which pressurizes the 1st fuel to the fuel injection valve 30, and the path|route through which the 1st fuel is pressurized. A first infusion pump (51) and a second infusion pump (61) are provided.

As shown in FIG. 1 , the fuel pump 41 , the first injection pump 51 , and the second injection pump 61 are laid out in the vicinity of the cylinder 16 , and respectively, the internal path 32 , the fuel It is fluidly connected to the fuel injection valve 30 via the injection pipe 42, the downstream injection pipe 52, the upstream injection pipe 62, etc.

Among these, the fuel pump 41 is connected to the fuel injection valve 30 through the fuel path L from the fuel pump 41 to the injection port 31, and is the 1st toward this fuel injection valve 30. pressurize fuel This fuel path L consists of the 1st internal path 32 and the fuel injection pipe 42 (it also includes the branch pipe 42a mentioned later), and connects the fuel pump 41 and the injection port 31. It is structured as a path to Further, the first injection pump 51 and the second injection pump 61 are respectively connected to the fuel path L via the downstream injection pipe 52 and the upstream injection pipe 62, A second fuel is injected into the fuel path (L).

By configuring in this way, the fuel injection valve 30 injects the first fuel pressurized from the fuel pump 41 and the second fuel injected by the first injection pump 51 and the second injection pump 61 into fuel. By the pressure-feeding action of the pump 41, it is possible to alternately (that is, in a layered manner) inject into the combustion chamber 17 .

In this way, the fuel injection valve 30 supplies the first fuel and the second fuel to the combustion chamber 17 , and generates combustion in the combustion chamber 17 . Due to this combustion, the piston 21 reciprocates in the vertical direction. At this time, when the exhaust valve 18 is actuated and the combustion chamber 17 is opened, the exhaust gas generated by combustion is pushed out into the exhaust pipe 19 and gas is introduced into the combustion chamber 17 from a scavenging port (not shown). do.

Moreover, when the piston 21 reciprocates by combustion, the piston rod 22 reciprocates with the piston 21 in an up-down direction. As a result, the crosshead 25 connected to the piston rod 22 reciprocates in the vertical direction. The crosshead 25 allows rotation of the connecting rod 24 , and rotates the connecting rod 24 by using the connecting portion with the crosshead 25 as a fulcrum. And the crank 27 connected to the lower end of the connecting rod 24 cranks, and the crankshaft 23 rotates according to the crank motion. In this way, the crankshaft 23 converts the reciprocating motion of the piston 21 into rotational motion, and rotates the propeller of a ship together with a propeller shaft. Thereby, the ship propels.

(2) Configuration related to fuel injection device

Hereinafter, the fuel injection valve 30 and various devices for supplying the first fuel and the second fuel to the fuel injection valve 30 are collectively referred to as a fuel injection device, and the code “100” is attached to this, and explanation is given. do In addition, the arrow shown by the solid line in FIG. 2 has shown the circulation of the 1st fuel and the 2nd fuel, and the arrow shown with the broken line has shown the sending/receiving of an electric signal.

As shown in FIG. 2 , the fuel injection device 100 according to the present embodiment includes, as main components, a plurality of (three in this embodiment) fuel injection valves 30 and for pressurizing the first fuel. The pressure-feed system 40, the injection systems 50 and 60 for injecting a 2nd fuel, and the control part 92 for controlling the pressure-feed system 40 and the injection systems 50 and 60 are provided.

Among these, the fuel injection valve 30 has the injection port 31 for injecting the fossil fuel as a 1st fuel, and the alternative fuel as a 2nd fuel, as mentioned above, The fuel via the fuel path L It is connected to the pump 41 .

On the other hand, the injection systems 50 and 60 are comprised so that the 2nd fuel may be injected into the predetermined positions P1 and P2 in the fuel path L. In particular, the injection systems 50 and 60 according to the present embodiment include the downstream injection system 50 for injecting the second fuel into the predetermined first injection position P1 in the fuel path L, and the fuel; It has an upstream injection system 60 which injects a 2nd fuel into the 2nd injection position P2 upstream from the 1st injection position P1 in the path|route L.

The fuel injection device 100 also includes, as other components, an alternative fuel supply pump 71 for supplying the second fuel to the injection systems 50 and 60 , the pressure feeding system 40 , and the injection systems 50 , 60 . .

Hereinafter, the fuel injection valve 30 , the pressure feed system 40 , the downstream injection system 50 , the upstream injection system 60 , the alternative fuel supply pump 71 , the pressure accumulator 81 , the detection unit 91 and The configuration of the control unit 92 will be described in turn.

(fuel injection valve (30))

The plurality of fuel injection valves 30 are injection valves for injecting the first fuel and the second fuel in a layered manner to the combustion chamber 17 in the cylinder 16 as described above. Three fuel injection valves 30 are provided in each cylinder 16 of the engine 1 (in the example shown in FIG. 3, only one is shown for convenience of description). These several fuel injection valves 30 are respectively comprised similarly. Then, below, one of these some fuel injection valves 30 is taken as an example, and the structure related to the fuel injection valve 30 is demonstrated.

As shown in FIG. 2 , the fuel injection valve 30 is connected to the fuel pump 41 in the pressure feeding system 40 via a fuel injection pipe 42 or the like. In addition, the fuel injection valve 30 is an upstream injection pipe 62 and a downstream injection from the 1st injection pump 51 and the 2nd injection pump 61 in the injection systems 50 and 60, respectively. They are connected via a tube 52 or the like. As shown in FIG. 3 , the fuel injection valve 30 includes a first fuel (diesel fuel as fossil fuel) pumped under pressure by the fuel pump 41, and a second fuel injected by the downstream injection system 50 ( ammonia as an alternative fuel), the first fuel pumped by the fuel pump 41 (diesel fuel as a fossil fuel), and the second fuel injected by the upstream injection system 60 (ammonia as an alternative fuel), and fuel The layered liquid 200 containing the fuel layers F1, A1, F2, A2, F3 arranged in order of the first fuel (diesel fuel as fossil fuel) pumped by the pump 41 is fed from the injection port 31 to the combustion chamber ( 17) Spray inside.

In detail, as shown in FIG. 2 , the fuel injection valve 30 includes the injection port 31 configured as described above, two internal paths 32 and 33 leading to the injection port 31 , and two It has check valves 34a and 34b.

One internal path 32 of the two internal paths 32 and 33 is a path for mainly allowing the first fuel to flow, and includes a branch pipe 42a in the fuel injection pipe 42 and an injection port 31 . is connecting to Hereinafter, the one internal path|route 32 is called "the 1st internal path|route 32". An upstream injection pipe 62 in the upstream injection system 60 (specifically, a branch pipe 62a in the upstream injection pipe 62) is checked in the first internal path 32 . It is connected via the valve 34a. The upstream injection pipe 62 extends from the second injection pump 61 and is a pipe through which the second fuel pressure fed from the second injection pump 61 flows. Accordingly, not only the first fuel but also the second fuel injected from the upstream injection pipe 62 flows through the first internal path 32 .

Moreover, the 1st internal path|route 32 which concerns on this embodiment comprises the fuel path|route L from the fuel pump 41 to the injection port 31 together with the fuel injection pipe 42. As shown in FIG. The portion where the branch pipe 62a is connected to the first internal path 32 indicates a position in the fuel path L where the second fuel is injected by the upstream injection system 60 . This position is the same as the above-mentioned "2nd injection position P2".

In addition, the other internal path 33 among the two internal paths 32 and 33 is a path for flowing the second fuel, and the downstream injection pipe 52 (specifically) in the downstream injection system 50 . The branch pipe 52a) in the downstream injection pipe 52 is connected to a site in the vicinity of the injection port 31 in the first internal path 32 . Hereinafter, the downstream injection pipe 52 in which the other internal path 33 is referred to as a "second internal path 33" is extended from the first injection pump 51, and the first injection pump 51 ) is a pipe that circulates the pressurized second fuel. Accordingly, the second fuel that has passed through the downstream injection pipe 52 flows through the second internal path 33 .

In addition, the portion where the second internal path 33 is connected to the first internal path 32 indicates a position where the second fuel is injected by the downstream injection system 50 in the fuel path L. there is. This position is the same as the above-mentioned "first injection position P1". As shown in FIG. 2 , the second injection position P2 is provided on the upstream side of the first injection position P1 in the fuel path L. As shown in FIG. In addition, the "upstream side" here refers to the upstream side in the flow direction of a 1st fuel. In addition, the "circulation direction of a 1st fuel" refers to the direction which goes to the injection port 31 via the fuel injection pipe 42 etc. from the fuel pump 41 .

One check valve 34a among the two check valves 34a and 34b allows the flow of the second fuel from the upstream injection system 60 to the first internal path 32, and the second Prevent backflow of fuel. The other non-return valve 34b is formed in the middle portion of the second internal path 33 . This other non-return valve 34b allows the flow of the second fuel from the downstream injection system 50 to the first internal path 32 via the second internal path 33, and 2 Prevent backflow of fuel.

(Pressure system (40))

The pressure feeding system 40 is an installation for pressure feeding the first fuel to the fuel injection valve 30 . As shown in FIG. 2 , the pressure feeding system 40 includes a fuel pump 41 , a fuel injection pipe 42 , and a control valve 45 .

The fuel pump 41 is a hydraulically driven pump that pumps fuel by using the pressure of hydraulic oil. In detail, the fuel pump 41 is connected with the fuel tank (not shown) in which the fossil fuel as 1st fuel was stored through piping etc., and takes in fuel from this fuel tank. The fuel pump 41 pressurizes the fuel received from the fuel tank to the fuel injection valve 30 via the fuel injection pipe 42 . Moreover, the pressure-feeding action|action of the fuel pump 41 can also make the fuel injection valve 30 perform layered injection of a 1st fuel and a 2nd fuel.

The fuel injection pipe 42 is a pipe for allowing fuel to flow between the fuel pump 41 and the fuel injection valve 30 . For example, as shown in FIG. 2 , one end of the fuel injection pipe 42 is connected to a discharge port of the fuel pump 41 . Moreover, the branch part 43 is formed in the intermediate part of the fuel injection pipe 42. As shown in FIG. The fuel injection pipe 42 is branched from this branching part 43 into a plurality of branch pipes toward the other end. Specifically, the fuel injection pipe 42 according to the present embodiment branches from the branch portion 43 into three branch pipes 42a, 42b, and 42c. Among these branch pipes 42a, 42b, and 42c, the first branch pipe 42a is connected to the first internal path 32 of one fuel injection valve 30, as shown in FIG. The fuel injection pipe 42 communicates the fuel pump 41 with the first internal path 32 in the fuel injection valve 30 via the branch pipe 42a. Similarly to this, the remaining branch pipes 42b and 42c are respectively connected to the other fuel injection valves 30 .

In addition, the structure which forms the branch part 43 in the intermediate part of the fuel injection pipe 42 is not essential. Instead of providing the branch part 43, it is good also considering the fuel injection pipe 42 as a plurality (for example, three).

The control valve 45 is a valve for controlling the supply of hydraulic oil from the pressure accumulator 81 to the fuel pump 41 . Specifically, the control valve 45 is constituted by an electric on/off valve such as a solenoid valve, and although not shown, by opening and closing a logic valve driven by the control valve 34, as shown in FIG. 2 , The fuel pump 41 and the pressure accumulator 81 are formed so that communication is possible. The control valve 45 enters an open state during a period during which the first fuel is injected (hereinafter, simply referred to as an "injection period"), and supplies the hydraulic oil in the pressure accumulator 81 to the fuel pump 41 . The fuel pump 41 pressurizes the 1st fuel to the fuel injection valve 30 using the pressure of this supplied hydraulic oil. On the other hand, the control valve 45 enters a closed state in a period other than the injection period of 1st fuel, and stops supply of the hydraulic oil from the pressure accumulator 81 to the fuel pump 41 . The opening and closing of this control valve 45 is controlled by the control unit 92 .

(Downstream injection system (50))

As shown in FIG. 2 , the downstream injection system 50 includes the first injection pump 51 , the downstream injection pipe 52 , the check valve 54 , and the first control valve 55 . has a The downstream injection system 50 is an example of the "first injection system" in this embodiment.

The first injection pump 51 is a hydraulically driven pump that injects the second fuel using the pressure of hydraulic oil. Specifically, the first injection pump 51 receives the alternative fuel from the alternative fuel supply pump 71 via the supply pipe 72 or the like. The first injection pump 51 pressurizes the received alternative fuel as the second fuel. The second fuel pumped by pressure from the first injection pump 51 passes through the downstream injection pipe 52 and the second internal path 33 in the fuel injection valve 30 , and the fuel injection valve 30 . leads to the first internal path 32 in In this way, the first injection pump 51 injects the replacement fuel as the second fuel into the first injection position P1 of the fuel path L.

The downstream injection pipe 52 is a pipe for flowing the second fuel injected into the fuel path L by the first injection pump 51 . For example, as shown in FIG. 2 , one end of the downstream injection pipe 52 is connected to a discharge port of the first injection pump 51 . Moreover, the branching part 53 is formed in the middle part of the downstream injection pipe 52. As shown in FIG. The downstream injection pipe 52 is branched from this branch part 53 into a plurality of branch pipes toward the other end. Specifically, the downstream injection pipe 52 according to the present embodiment branches from the branch 53 into three branch pipes 52a, 52b, and 52c. Of these branch pipes 52a, 52b, and 52c, the first branch pipe 52a is connected to the second internal path 33 of one fuel injection valve 30, as shown in FIG. The downstream injection pipe 52 communicates with the second internal path 33 in the fuel injection valve 30 and the first injection pump 51 via the branch pipe 52a. Similarly to this, the remaining branch pipes 52b and 52c are respectively connected to the other fuel injection valves 30 .

In addition, the structure which forms the branch part 53 in the intermediate part of the downstream injection pipe 52 is not essential. Instead of providing the branch part 53, it is good also considering the downstream injection tube 52 as a plurality (for example, three).

The check valve 54 is a valve for regulating the flow direction of the second fuel in the downstream injection pipe 52 in one direction to prevent a reverse flow of the second fuel. As shown in FIG. 2 , the check valve 54 is formed at an intermediate portion of the downstream injection pipe 52 , for example, between the first injection pump 51 and the branching portion 53 . . The check valve 54 permits the flow of the second fuel from the first injection pump 51 to the second internal path 33 via the branch 53 and prevents a reverse flow of the second fuel. prevent.

The first control valve 55 is a valve for controlling the supply of hydraulic oil from the pressure accumulator 81 to the first injection pump 51 . Specifically, the first control valve 55 is constituted by an electric on/off valve such as a solenoid valve, so that the first injection pump 51 and the pressure accumulator 81 can communicate with each other as shown in FIG. 2 . is formed The first control valve 55 controls the period during which the second fuel pumped from the first injection pump 51 is injected into the fuel path L (hereinafter referred to as “the injection period of the downstream injection system 50 ”, “ In an open state during the "injection period by the downstream injection system 50" or simply "the first injection period"), the hydraulic oil in the pressure accumulator 81 is supplied to the first injection pump 51 . The first injection pump 51 pressurizes and injects the second fuel to the first injection position P1 in the fuel path L by using the pressure of the supplied hydraulic oil. On the other hand, the first control valve 55 enters a closed state in a period other than the injection period by the downstream injection system 50 , and stops the supply of hydraulic oil from the pressure accumulator 81 to the first injection pump 51 . do. The opening and closing of the first control valve 55 is controlled by the control unit 92 .

(Upstream injection system (60))

As shown in FIG. 2 , the upstream injection system 60 includes the second injection pump 61 , the upstream injection pipe 62 , the check valve 64 , and the second control valve 65 . has a The upstream injection system 60 is an example of the "second injection system" in this embodiment.

The second injection pump 61 is a hydraulically driven pump that injects the second fuel using the pressure of hydraulic oil. Specifically, the second injection pump 61 receives the alternative fuel from the alternative fuel supply pump 71 via the supply pipe 72 or the like. The second injection pump 61 pressurizes the received alternative fuel as the second fuel. The second fuel pumped under pressure from the second injection pump 61 reaches the first internal path 32 in the fuel injection valve 30 through the upstream injection pipe 62 . In this way, the 2nd injection pump 61 injects the replacement fuel as a 2nd fuel into the 2nd injection position P2 of the fuel path L.

The upstream injection pipe 62 is a pipe for flowing the second fuel injected into the fuel path L by the second injection pump 61 . For example, as shown in FIG. 2 , one end of the upstream injection pipe 62 is connected to a discharge port of the second injection pump 61 . Moreover, the branching part 63 is formed in the middle part of the upstream injection pipe 62. As shown in FIG. The upstream injection pipe 62 is branched from the branch 63 toward the other end into a plurality of branch pipes. Specifically, the upstream injection pipe 62 according to the present embodiment branches from the branch portion 63 into three branch pipes 62a, 62b, and 62c. Of these branch pipes 62a, 62b, and 62c, the first branch pipe 62a is, as shown in FIG. 2, a first internal path ( 32) is connected. The upstream injection pipe 62 communicates with the first internal path 32 in the fuel injection valve 30 and the second injection pump 61 via the branch pipe 62a. Similarly to this, the remaining branch pipes 62b and 62c are respectively connected to the other fuel injection valves 30 .

In addition, the structure which forms the branch part 63 in the intermediate part of the upstream injection pipe 62 is not essential. Instead of providing the branch part 63, it is good also considering the upstream injection tube 62 as a plurality (for example, three).

The check valve 64 is a valve for regulating the flow direction of the second fuel in the upstream injection pipe 62 in one direction to prevent a reverse flow of the second fuel. As shown in FIG. 2 , the check valve 64 is formed at an intermediate portion of the upstream injection pipe 62 , for example, between the second injection pump 61 and the branching portion 63 . . The check valve 64 permits the flow of the second fuel from the second injection pump 61 to the first internal path 32 via the branch 63 and prevents a reverse flow of the second fuel. prevent.

The second control valve 65 is a valve for controlling the supply of hydraulic oil from the pressure accumulator 81 to the second injection pump 61 . Specifically, the second control valve 65 is constituted by an electric on/off valve such as a solenoid valve, and as shown in FIG. 2 , the second injection pump 61 and the pressure accumulator 81 can communicate with each other. is formed The second control valve 65 controls the period during which the second fuel pumped from the second injection pump 61 is injected into the fuel path L (hereinafter referred to as “the injection period of the upstream injection system 60 ”, “ In an open state during the "injection period by the upstream injection system 60" or simply "the second injection period"), the hydraulic oil in the pressure accumulator 81 is supplied to the second injection pump 61 . The 2nd injection pump 61 pressurizes and injects the 2nd fuel to the 2nd injection position P2 in the fuel path L using the pressure of this supplied hydraulic oil. On the other hand, the second control valve 65 enters a closed state in a period other than the injection period by the upstream injection system 60 , and stops the supply of hydraulic oil from the pressure accumulator 81 to the second injection pump 61 . do. The opening and closing of the second control valve 65 is controlled by the control unit 92 .

(Alternative fuel feed pump (71))

The alternative fuel supply pump 71 is a pump for supplying the alternative fuel injected into the fuel path L as the second fuel to the first injection pump 51 and the second injection pump 61 . As shown in FIG. 2 , the alternative fuel supply pump 71 is connected to the first injection pump 51 and the second injection pump 61 via a supply pipe 72 or the like so that communication is possible.

Specifically, one end of the supply pipe 72 is connected to an alternative fuel supply pump 71 , and the other end of the supply pipe 72 is branched into two, the first injection pump 51 and the second injection pump 61 . ) is connected to In detail, the supply pipe 72 is branched into branch pipes 72a, 72b in the site|part in the middle. One branch pipe 72a branched from the supply pipe 72 is connected to the first injection pump 51 via a check valve 73a. The other branch pipe 72b among the branches is connected to the second injection pump 61 via a check valve 73b.

The alternative fuel supply pump 71 which concerns on this embodiment is connected with the tank (not shown) storing the alternative fuel as 2nd fuel, The alternative fuel stored in this tank is connected to the branch pipes 72a, 72b. ) is supplied to the first injection pump 51 and the second injection pump 61 through the

The check valve 73a permits flow of the second fuel from the alternative fuel supply pump 71 toward the first injection pump 51 and prevents a reverse flow of the second fuel. The check valve 73b allows flow of the second fuel from the alternative fuel supply pump 71 toward the second injection pump 61 and prevents a reverse flow of the second fuel.

(Pressure accumulator (81))

The pressure accumulator 81 accumulates hydraulic oil for operating the pressure feed system 40 and the injection systems 50 and 60 , respectively. The pressure accumulation part 81 is a hollow structure which has a pressure accumulation chamber which can store hydraulic oil, and is connected with the high pressure pump 82 as shown in FIG. The pressure accumulator 81 stores the hydraulic oil pressurized from the high-pressure pump 82 and condenses it. The pressure of the hydraulic oil in the pressure accumulator 81 is adjusted by the discharge amount of the hydraulic oil from the high pressure pump 82 to the pressure accumulator 81 . The pressure of the hydraulic oil in the pressure accumulator 81 is the fuel pump 41 in the pressure feeding system 40 , the first injection pump 51 in the downstream injection system 50 , and the upstream injection It is shared by the second injection pump 61 in the system 60 .

(detector (91))

The detection unit 91 detects the crank angle of the engine 1 . The detection part 91 which concerns on this embodiment detects the rotation angle (so-called "crank angle") of the crank 27 which rotates with the reciprocating motion of one cycle of the piston 21. As shown in FIG. In that case, the detection part 91 detects the rotation angle from the reference state of the crank 27 as a crank angle. In addition, as a reference state of the crank 27, the state of the crank 27 when the piston 21 is located at bottom dead center or top dead center, etc. are mentioned, for example. The detection unit 91 detects a crank angle that changes with the passage of time, and transmits an electric signal indicating the detected crank angle to the control unit 92 each time.

(control unit (92))

The control unit 92 includes a control valve 45 of the pressure feeding system 40 , a first control valve 55 of the downstream injection system 50 , and a second control valve of the upstream injection system 60 ( 65) to control the opening and closing. Thereby, the control part 92 controls the layer injection timing by the fuel injection valve 30, the timing that the downstream injection system 50 injects the 2nd fuel, and the upstream injection system 60 injects the second fuel. The timing of injection can be controlled.

In addition, in this embodiment, the layered injection timing by the fuel injection valve 30 means the timing which injects the 1st fuel and the 2nd fuel in layers from the fuel injection valve 30 to the combustion chamber 17 .

In addition, the timing at which the downstream injection system 50 injects the second fuel includes the timing at which the downstream injection system 50 starts injection of the second fuel (hereinafter referred to as "first-layer injection start timing"); , a timing at which the downstream injection system 50 ends injection of the second fuel (hereinafter referred to as “first-layer injection termination timing”) are included. Similarly, the timing at which the upstream injection system 60 injects the second fuel is the timing at which the upstream injection system 60 starts injecting the second fuel (hereinafter referred to as “second layer injection start timing”). and the timing at which the upstream injection system 60 ends injection of the second fuel (hereinafter referred to as "second-layer injection termination timing") are included.

Specifically, the control unit 92 is constituted by a CPU for executing various programs, a memory, a sequencer, and the like. The control unit 92 receives the electrical signal from the detection unit 91, and the control valve 45 of the pressure feeding system 40 becomes an open state at the timing at which the crank angle shown in the received electrical signal becomes a predetermined rotation angle. control the opening and closing of The control unit 92 controls the timing at which the fuel pump 41 operates through the control of the control valve 45 . Thereby, the control part 92 controls the layered injection timing by the fuel injection valve 30.

In particular, the control unit 92 according to the present embodiment includes, among the fuels injected into the combustion chamber 17 at the layered injection timing, two or more fuel layers composed of the first fuel and the fuel layer composed of the second fuel. The injection system 50, 60 is controlled so that it may become this.

At this stratified injection timing, the first fuel in a required amount according to the engine load among the first fuels pressurized to the fuel path L by the fuel pump 41 and the fuel path L by the first injection pump 51 The second fuel injected into the first injection position P1 of the fuel pump 41 and the second fuel injected into the second injection position P2 of the fuel path L by the second injection pump 61 are It is injected in layers from the fuel injection valve 30 to the combustion chamber 17 by the pressure feeding action of

As a result, the fuel injection valve 30 which concerns on this embodiment is 1st fuel pumped by the fuel pump 41, and the 2nd fuel injected by the downstream injection system 50, as shown in FIG. , the first fuel pumped by the fuel pump 41 , the second fuel injected by the upstream injection system 60 , and the first fuel pumped by the fuel pump 41 , in the order of which the layered liquid is arranged in the combustion chamber (17) will be sprayed within. Thereafter, the fuel path L illustrated in FIGS. 2 and 3 is in a state filled with the remaining first fuel without being injected.

Moreover, in the period other than the above-mentioned layered injection timing of the 1st fuel and the 2nd fuel, the control part 92 is a fuel path L which is in the state filled with the 1st fuel, In particular, in the fuel path L, The timing at which the downstream injection system 50 injects the second fuel so as to inject the second fuel into each of the first injection position P1 and the second injection position P2 of the The timing of injecting the second fuel is controlled.

At this time, the control unit 92 controls the downstream injection system (hereinafter simply referred to as "engine load") according to the load of the engine 1 so that at least a part of the first injection period and the second injection period overlap. 50) The timing for starting the injection of the second fuel and the timing for starting the injection of the second fuel by the upstream injection system 60 are controlled.

(3) Control according to engine load

Hereinafter, during the processing executed by the control unit 92, control according to the engine load will be described in detail. FIG. 4 is a diagram illustrating the layered liquid in the fuel path L, and FIG. 5 is a diagram illustrating the timing of injecting the second fuel. Moreover, FIG. 6 is a figure for demonstrating the quantity of 1st fuel, and FIG. 7 is a figure for demonstrating the injection quantity according to engine load.

In the present embodiment, by injecting the second fuel into the fuel path L which is in a state filled with the first fuel, the layered liquid containing at least the three layers of the first fuel and the second fuel is transferred to the fuel path L ) is formed in The "injection port side" in FIG. 4 refers to the injection port 31 side of the fuel injection valve 30, ie, the flow direction downstream side of the 1st fuel in the fuel path L. In addition, the "fuel pump side" in the figure refers to the fuel pump 41 side of the pressure feeding system 40, ie, the flow direction upstream side of the 2nd fuel in the fuel path L. The layered liquid 200 illustrated in Fig. 4 has a plurality of liquid layers arranged from the injection port side toward the fuel pump side, for example, a first liquid layer (L1), a second liquid layer (L2), and a third liquid layer. (L3), a fourth liquid layer (L4) and a fifth liquid layer (L5).

The first liquid layer L1 is the most downstream liquid layer among the layered liquids 200 . The 1st liquid layer L1 is a fuel layer which consists of 1st fuel in this embodiment. Hereinafter, while calling this fuel layer "a downstream fuel layer", the code|symbol "F1" is attached|subjected. The downstream fuel layer F1 is the first fuel layer counted from the injection port side among the fuel layers composed of a plurality (three in the drawing example) of the first fuel contained in the layered liquid 200, and It consists of a predetermined amount of fuel present at the most downstream in the flow direction. The downstream fuel layer F1 is formed of the 1st fuel which distribute|circulates the fuel path|route L.

The second liquid layer L2 is a liquid layer immediately upstream of the first liquid layer L1 in the layered liquid 200 . The 2nd liquid layer L2 is a fuel layer which consists of a 2nd fuel in this embodiment. Hereinafter, this fuel layer is called "downstream injection layer" and code|symbol "A1" is attached|subjected. The downstream injection layer A1 is the first fuel layer counted from the injection port side among the fuel layers composed of a plurality of (two in the drawing example) second fuel contained in the layered liquid 200 . This downstream injection layer A1 is formed by injecting a required amount of the second fuel into the first injection position P1 by the first injection pump 51 .

The third liquid layer L3 is a liquid layer immediately upstream of the second liquid layer L2 in the layered liquid 200 . The 3rd liquid layer L3 is a fuel layer which consists of 1st fuel in this embodiment. Hereinafter, while calling this fuel layer "intermediate fuel layer", the code|symbol "F2" is attached|subjected. The intermediate fuel layer F2 is a fuel layer of the 2nd layer counting from the injection port side among the fuel layers which consist of a some 1st fuel contained in the layered liquid 200. As shown in FIG. This intermediate fuel layer F2 consists of a second fuel injected at the first injection position P1 and a second fuel injected at the second injection position P2 among the first fuels flowing through the fuel path L. It consists of a first fuel sandwiched in between.

The fourth liquid layer L4 is a liquid layer immediately upstream of the third liquid layer L3 in the layered liquid 200 . The fourth liquid layer L4 is a fuel layer made of the second fuel in the present embodiment. Hereinafter, this fuel layer is called "upstream injection layer" and code|symbol "A2" is attached|subjected. The upstream injection layer A2 is the second fuel layer counted from the injection port side among the fuel layers composed of the plurality of second fuels contained in the layered liquid 200 . This upstream injection layer A2 is formed by injecting a required amount of the second fuel into the second injection position P2 by the second injection pump 61 .

The fifth liquid layer L5 is an uppermost liquid layer among the layered liquids 200 . The 5th liquid layer L5 is a fuel layer which consists of 1st fuel in this embodiment. Hereinafter, this fuel layer is called "upstream side fuel layer" and code|symbol "F3" is attached|subjected. The upstream fuel layer F3 is a fuel layer of the third layer, counting from the injection port side, among the fuel layers composed of the plurality of first fuels contained in the layered liquid 200 . This upstream fuel layer F3 consists of the 1st fuel which exists in the immediate upstream of the 4th liquid layer L4 among the 1st fuels which flow through the fuel path L.

The layered liquid 200 composed of the first fuel and the second fuel is injected from the injection port 31 to the combustion chamber 17 for each reciprocating motion of the piston 21 in one cycle. At this time, the injection amount per one time of the first fuel to the combustion chamber 17, that is, the total amount of the first fuel contained in the layered liquid 200 (hereinafter also simply referred to as “first fuel injection amount”) Qfa is , the sum of the amount Qf1 of the downstream fuel layer F1, the amount Qf2 of the intermediate fuel layer F2, and the amount Qf3 of the upstream fuel layer F3 (= Qf1 + Qf2 + Qf3) represented by This first fuel injection amount Qfa increases with an increase in the engine load and decreases with a decrease.

Moreover, in the layered liquid 200, the quantity of the 1st fuel located between the downstream and upstream injection layers A1 and A2 which consist of a 2nd fuel, ie, 1st fuel in the intermediate|middle fuel layer F2. The amount Qf2 is the timing at which the downstream injection system 50 starts injection of the second fuel (the first layer injection start timing) and the timing at which the upstream injection system 60 starts injection of the second fuel. (2nd layer injection start timing). In that case, the quantity Qf2 of the 1st fuel in the intermediate|middle fuel layer F2 is controllable so that it may become a fixed ratio with respect to the 1st fuel injection quantity Qfa determined by the engine load.

On the other hand, the injection amount per one time of the second fuel to the combustion chamber 17, that is, the total amount of the second fuel contained in the layered liquid 200 (hereinafter also simply referred to as "second fuel injection amount") (Qaa) is, It is expressed by the sum (= Qa1 + Qa2) of the injection amount Qa1 of the second fuel in the downstream injection layer A1 and the injection amount Qa2 of the second fuel in the upstream injection layer A2. This second fuel injection amount Qaa increases when it is determined that the ignition of the first fuel is unstable based on the operating state of the engine 1, and decreases when it is determined that the ignition of the first fuel is stable. . At this time, the injection amount Qa1 of the second fuel in the downstream injection layer A1 formed by the downstream injection system 50 and the upstream injection layer formed by the upstream injection system 60 ( The ratio of the injection amount Qa2 of the second fuel in A2) is preferably constant.

Next, the control for adjusting the quantity Qf2 of the 1st fuel in the intermediate|middle fuel layer F2 is demonstrated in detail using FIG.5 and FIG.6. In FIG. 5 , the first control signal S1 is a control signal for opening and closing the first control valve 55 associated with the first injection pump 51 . The second control signal S2 is a control signal for opening and closing the second control valve 65 associated with the second infusion pump 61 . The code|symbol "201" in FIG. 6 has shown the columnar 1st fuel which remain|survives in the fuel path L.

As described above, the control unit 92 controls the first-layer injection start timing and the second-layer injection start timing according to the engine load so that at least a part of the first injection period and the second injection period overlap.

At this time, the control unit 92 is located between the downstream injection layer A1 formed by the downstream injection system 50 and the upstream injection layer A2 formed by the upstream injection system 60 . First layer injection so that the amount of the first fuel to be used (the amount of the first fuel in the intermediate fuel layer F2) Qf2 becomes a constant ratio to the first fuel injection amount Qfa determined according to the engine load The initiation timing and the initiation timing of the second layer implantation can be controlled.

Specifically, the control unit 92 calculates the predetermined waiting time ΔT based on the engine load. The waiting time ΔT represents the period between the first-layer implantation start timing and the second-layer implantation start timing. The waiting time ΔT is, for example, an engine speed corresponding to the engine load (engine revolutions per unit time), a first fuel injection amount (injection amount per one time of the first fuel), and a second fuel injection amount ( The amount of the second fuel injected into the first fuel for one injection dose) is expressed as the following formula (1) by the function f(x, y, z) when the independent variables x, y, z are respectively used.

ΔT = f(x, y, z) … (One)

For example, the control unit 92 calculates the standby time ΔT such that the standby time ΔT increases with an increase in the engine load and the standby time ΔT decreases with a decrease in the engine load. . In addition, the function f(x, y, z) can be derived, for example, based on simulation and experimental results of the engine 1, and the like. The control unit 92 stores the formula (1) in advance.

The control unit 92 calculates the waiting time ΔT1 of the downstream injection system 50 as the waiting time ΔT based on the formula (1). The control unit 92 delays the injection start timing of the first layer from the injection start timing of the second layer by the amount of the waiting time ΔT1.

Specifically, the control unit 92 acquires the crank angle appearing in the electric signal received from the detection unit 91 as the crank angle at the detection time (hereinafter referred to as "current crank angle"). The control unit 92 outputs an electric signal to the second control valve 65 of the upstream injection system 60 at the timing T1 at which the current crank angle becomes the predetermined first crank angle R1, and this keep it open When the second control valve 65 is opened, the second injection pump 61 in the upstream injection system 60 starts operation. That is, this timing T1 is the same as the "second layer injection start timing" when the upstream injection system 60 starts injection of the second fuel. At this second-layer injection start timing T1 , as shown in FIG. 6 , injection of the second fuel 202 is started at the second injection position P2 in the fuel column 201 .

In addition, in the period T0 from the end of the previous layer injection until the second injection start timing T1 is reached, as shown in FIG. 6 , the second fuel is not injected into the fuel column 201 . not. The amount of fuel in the fuel column 201 at this time corresponds to the above-described first fuel injection amount Qfa.

Next, the control unit 92 controls injection of the second fuel by the downstream injection system 50 at a timing delayed from the injection start timing T1 of the second layer by the amount of the waiting time ΔT1 calculated as described above. start Specifically, the control unit 92 converts the waiting time ΔT1 of the downstream injection system 50 into a change amount ΔR of the crank angle based on the engine rotation speed and the elapsed time of the engine rotation. The control unit 92 calculates the second crank angle R2 by adding the obtained change amount ΔR of the crank angle and the first crank angle R1 at the injection start timing T1 of the second layer. As shown in FIG. 5 , the control unit 92 sends an electrical signal to the first control valve 55 of the downstream injection system 50 at the timing T2 at which the current crank angle becomes the second crank angle R2. is output, and this is set to an open state. When the first control valve 55 is opened, the first injection pump 51 in the downstream injection system 50 starts to operate while the operation of the second injection pump 61 continues. That is, this timing T2 is the same as the "first-layer injection start timing" at which the downstream injection system 50 starts injection of the second fuel. At this first-layer injection start timing T2 , as shown in FIG. 6 , the second fuel 202 is continuously injected into the second injection position P2 in the fuel column 201 , Injection of the second fuel 203 to the first injection position P1 is started.

Thereafter, the second injection pump 61 continues to inject the second fuel into the second injection position P2 for a period until the second control valve 65 is in the closed state. In parallel with this, the first injection pump 51 continues to inject the second fuel into the first injection position P1 for a period until the first control valve 55 is in the closed state.

As illustrated in FIGS. 5 and 6 , the period ΔT2 from the second crank angle R2 to the predetermined third crank angle R3 (> R2) is the While injection of the 2nd fuel 202 advances, injection of the 2nd fuel 203 in the 1st injection position P1 advances. The 1st fuel located between the 1st injection position P1 and the 2nd injection position P2 with injection of the 2nd fuel 203 in the 1st injection position P1 is a 2nd injection position It passes over the 2nd fuel 202 in (P2) and is pushed back to an upstream side in the flow direction. Thereby, the amount of the first fuel located between the first injection position P1 and the second injection position P2 is adjusted to decrease.

Then, at the timing T3 when the current crank angle becomes the 3rd crank angle R3, the 2nd fuel 202 in the 2nd injection position P2 spreads across the width direction of the fuel column 201. It is injected until it spreads. The "width direction" here is a direction orthogonal to the flow direction of a 1st fuel, and points out the width direction of the fuel path|route L. At this time, the 2nd fuel 202 in the 2nd injection position P2 is the downstream which locates the fuel column 201 downstream rather than the 2nd injection position P2, as illustrated in FIG. It divides into the side fuel 201a and the most upstream fuel 201b located on the upstream side rather than the 2nd injection position P2. In this step, the fuel positioned between the first injection position P1 and the second injection position P2 is It is prevented from being pushed back to the upstream side in the flow direction beyond the second fuel 202 at the second injection position P2. Thereby, adjustment of the quantity of the 1st fuel located between the 1st injection position P1 and the 2nd injection position P2 is complete|finished, and the total amount of the downstream fuel 201a is determined.

Thereafter, as illustrated in FIG. 5 , the control unit 92 controls the upstream injection system 60 at a timing T4 when the current crank angle becomes a predetermined fourth crank angle R4 (> R3). An electric signal is output to the 2nd control valve 65, and this is made into a closed state. This second control valve 65 is brought into the closed state, whereby the second infusion pump 61 stops operating while the first infusion pump 51 continues to operate. Thereby, the 2nd injection pump 61 complete|finishes injection of the 2nd fuel to the 2nd injection position P2. That is, the timing T4 at which the current crank angle becomes the fourth crank angle R4 is the same as the "second layer injection end timing" at which the upstream injection system 60 ends injection of the second fuel. On the other hand, the 1st injection pump 51 continues injecting the 2nd fuel to the 1st injection position P1.

As illustrated in FIGS. 5 and 6 , the period ΔT3 from the third crank angle R3 to the fourth crank angle R4 is the second fuel 202 at the second injection position P2. While being injected further in the state which spread over the width direction whole area of the fuel column 201, injection of the 2nd fuel 203 in the 1st injection position P1 will advance continuously. In this step, the injection of the second fuel 203 at the first injection position P1 is performed by injecting the second fuel 202 at the second injection position P2 together with the downstream fuel 201a. It is carried out while pressing in the upstream side in the distribution direction.

Moreover, when the current crank angle becomes the crank angle corresponding to the second-layer injection end timing T4, the required amount of the second fuel 202 at the second injection position P2 is injected. On the other hand, the 2nd fuel 203 in the 1st injection position P1 is in the injected state until it spreads over the width direction whole area of the fuel column 201. As shown in FIG. As for the 2nd fuel 203 of this state, the downstream fuel 201a of the fuel column 201 is located downstream from the 1st injection position P1, The most downstream fuel 201c, 1st and 1st It is divided into two injection interlayer fuels 201d sandwiched between the second fuels 202 and 203 at the injection positions P1 and P2. Thereby, the total amount of the fuel between injection layers 201d, that is, the amount of fuel between injection layers (=Qf2), and the amount of the most downstream fuel 201c are determined. In addition, the timing which injects until the 2nd fuel 203 in the 1st injection position P1 spreads over the width direction whole area of the fuel column 201 is the 2nd fuel in the 2nd injection position P2. 202 may be the same as the timing T4 at which the required amount is injected, the timing may be before the timing T4, or the timing after the timing T4 may be sufficient.

Thereafter, as illustrated in FIG. 5 , the control unit 92 sends the downstream injection system 50 to the timing T5 at which the current crank angle becomes the predetermined fifth crank angle R5 (> R4). An electric signal is output to the 1st control valve 55 in this, and this is made into a closed state. When the first control valve 55 is brought into the closed state, the first injection pump 51 stops operating. Accordingly, the first injection pump 51 ends the injection of the second fuel to the first injection position P1 . That is, the timing T5 at which the current crank angle becomes the fifth crank angle R5 is the same as the "first layer injection end timing" at which the downstream injection system 50 ends injection of the second fuel.

5 and 6 , in the period from the fourth crank angle R4 to the fifth crank angle R5, the second fuel 203 at the first injection position P1 is In the state spread over the width direction of the pillar 201, it is injected further. In this step, the injection of the second fuel 203 at the first injection position P1 is performed in the same manner as the period from the timing T3 to the timing T4 described above, and the second fuel ( 203) is continued until the required amount becomes the required amount. And at the timing T5 corresponding to the 5th crank angle R5, both injection of the 2nd fuel in the 1st injection position P1 and the 2nd injection position P2 will be complete|finished. As a result, the downstream fuel layer F1 made of the first fuel (in particular, the most downstream fuel 201c), the downstream injection layer A1 made of the second fuel 203, and the first fuel (especially, An intermediate fuel layer F2 composed of the injection interlayer fuel 201d), an upstream injection layer A2 composed of the second fuel 202, and an upstream side composed of the first fuel (particularly, the upstream fuel 201b) A layered liquid 200 in which the fuel layer F3 is aligned from the upstream side of the flow direction is formed in the fuel path L.

Here, in the present embodiment, the injection period (second injection period) of the upstream injection system 60 corresponds to the fourth crank angle R4 at the timing T1 corresponding to the first crank angle R1. This is the period until the timing T4. That is, the second injection period is a period obtained by adding the waiting time ?T1, the period ?T2, and the period ?T3 illustrated in FIG. 5 . This 2nd injection period is determined by the time required when injecting a required amount of the 2nd fuel 202 into the 2nd injection position P2 shown in FIG. That is, the fourth crank angle R4 corresponding to the second-layer injection end timing T4 related to the upstream injection system 60 is the first crank angle R1 corresponding to the second-layer injection start timing T1 and , is calculated based on the time required for injection of the required amount of the second fuel 202 .

In addition, the injection period (first injection period) of the downstream injection system 50 is a timing T2 corresponding to the second crank angle R2 to a timing T5 corresponding to the fifth crank angle R5. is the period until This first injection period is determined by the time required when injecting the required amount of the second fuel 203 into the first injection position P1. That is, the fifth crank angle R5 corresponding to the first-layer injection end timing T5 related to the downstream injection system 50 is the second crank angle R2 corresponding to the first-layer injection start timing T2 and , is calculated based on the time required for injection of the required amount of the second fuel 203 .

In the present embodiment, the period in which the first injection period and the second injection period overlap corresponds to the period ΔT4 from the second crank angle R2 to the fourth crank angle R4, as shown in FIG. 5 . do. This period (ΔT4) is a period (ΔT2) during which the amount of the first fuel is adjusted by the downstream injection system 50 to decrease the amount of the first fuel between the injection layers, and the adjustment of the first fuel between the injection layers is completed. Then, it is the time which added the period ((DELTA)T3) until the injection of the upstream injection system|strain 60 is complete|finished. The first-layer injection start timing by the downstream injection system 50 is such that the period ΔT2 decreases with an increase in the engine load and the period ΔT2 increases with the decrease of the engine load, the upstream injection system It is adjusted to a timing as slow as the waiting time (ΔT1) from the second layer implantation start timing (T1) by (60). That is, this waiting time ?T1 increases with an increase in the engine load, and decreases with a decrease in the engine load. In addition, when this waiting time (ΔT1) is a zero value (ΔT1 = 0), the first injection start timing by the downstream injection system 50 is the same as the second injection start timing by the upstream injection system 60 . controlled by the timing of

Here, the horizontal axis of FIG. 7 represents the engine load, and the vertical axis of the same figure represents the total injection amount per one time of the layered liquid 200 injected from one fuel injection valve 30 to the combustion chamber 17 . . This total injection amount is expressed by the sum (= Qfa + Qaa) of the first fuel injection amount Qfa and the second fuel injection amount Qaa according to the engine load.

In the present embodiment, the total injection amount is controlled through the first injection start timing by the downstream injection system 50 and the second injection start timing by the upstream injection system 60 . As illustrated in FIG. 7 , the total injection amount of the layered liquid 200 increases with an increase in the engine load, and decreases with a decrease in the engine load. At that time, in the layered liquid 200, the amount of the first fuel in the intermediate fuel layer F2 sandwiched between the downstream injection layer A1 and the upstream injection layer A2 (that is, the amount of fuel between the injection layers). ) is adjusted to an appropriate amount according to the engine load. Preferably, as illustrated in FIG. 7 , the first liquid layer (L1) to the fifth liquid layer (L5) (that is, the downstream fuel layer (F1), the downstream injection layer (A1), the intermediate fuel layer ( When the layered liquid 200 composed of F2), the upstream injection layer A2 and the upstream fuel layer F3 is formed, the amount of the first fuel (intermediate fuel layer F2) between the injection layers )) is adjusted (optimized) so that it becomes a constant ratio with respect to the first fuel injection amount Qfa that increases or decreases according to the engine load. Furthermore, in the layered liquid 200, the injection amount Qa1 of the second fuel in the downstream injection layer A1 and the injection amount Qa2 of the second fuel in the upstream injection layer A2 are The ratio is constant regardless of the engine load.

(4) Effect exhibited by injection of the secondary fuel

As described above, according to the present embodiment, the injection systems 50 and 60 can inject the second fuel into the fuel path L through which the first fuel flows. By injecting the second fuel into the fuel path L, for example, the first fuel, the second fuel, the first fuel, and the second fuel are sequentially injected in layers.

In this case, the second fuel is burned as the main fuel for generating power for driving the engine 1 , while the first fuel functions as a pilot fuel for igniting the main fuel. Here, the control part 92 is a fuel layer which consists of 1st fuel fuel layers F1, F2, F3, and fuel layer A1, A3 which consists of 2nd fuel among the fuel layers injected from the fuel injection valve 30. The injection systems 50 and 60 are controlled so that both are two or more layers.

By controlling in this way, as illustrated in FIG. 3 , the first fuel, the second fuel, the first fuel, the second fuel, and the first fuel are sequentially injected into the combustion chamber 17 in a layered manner. In this case, as illustrated in FIG. 6 , the second fuel injected following the first first fuel (the first fuel constituting the downstream fuel layer F1) is burned by the first first fuel. Combustion is promoted by the second fuel (the second fuel constituting the downstream injection layer A1) that is accelerated, and the second first fuel injected thereafter (the first fuel constituting the intermediate fuel layer F2). It is divided into 2 parts by the used 2nd fuel (the 2nd fuel which comprises the upstream injection layer A2). While the second fuel to be promoted is divided into two, the combustion of each of the second fuels divided into two can be promoted by the first fuel divided into two in the same manner as the second fuel. As a result, the combustion of the second fuel is promoted more reliably, and it becomes possible to suppress the generation of combustion residues.

Moreover, as illustrated in FIG. 7 , the downstream injection layer A1 injected by the downstream injection system 50 and the upstream injection layer A2 injected by the upstream injection system 60 . The quantity Qf2 of the 1st fuel in the intermediate|middle fuel layer F2 sandwiched by this can be adjusted according to an engine load. Thereby, it becomes possible to ensure the performance of the engine 1 .

That is, as illustrated in FIG. 5 , at least a part of the injection period (first injection period) by the downstream injection system 50 and the injection period (second injection period) by the upstream injection system 60 is The timing at which the downstream injection system 50 and the upstream injection system 60 each start injection of the second fuel is controlled in accordance with the engine load so as to overlap. Thereby, it becomes possible to control so that the ratio of the 1st fuel injection quantity Qfa which is determined according to the engine load and the fuel quantity Qf2 in the intermediate|middle fuel layer F2 does not become excessive or too small. Thereby, the operation of the engine 1 can be stabilized, and it becomes possible to ensure its performance.

Moreover, by using a fossil fuel as a 1st fuel, the facility for conveying a diesel fuel etc. can be diverted, and the pressure feeding system|system|group 40 can be comprised. Thereby, the manufacturing cost of a ship can be suppressed.

(5) Modification example of control according to engine load (first modification)

In the above embodiment, the control unit 92 calculates the waiting time ΔT1 based on the formula (1), and the downstream injection system 50 sends the second fuel by the amount of the waiting time ΔT1. The timing for starting the injection of , (1st layer injection start timing) is configured to be later than the timing at which the upstream injection system 60 starts injection of the second fuel (2nd layer injection start timing), but this configuration is limited doesn't happen

For example, in a modification shown below (hereinafter, referred to as a "first modification"), the control unit 92 calculates and calculates a predetermined waiting time ΔT11 based on the engine load. It is configured so that the injection start timing of the second layer is delayed from the timing of the injection start of the first layer by the amount of the waiting time ΔT11.

FIG. 8 is a diagram corresponding to FIG. 4 in the first modification of the engine 1 , and FIG. 9 is a diagram corresponding to FIG. 5 in the first modification of the engine 1 . In the following description, the same name and code|symbol as the said embodiment are used about the component comprised similarly to the said embodiment. Description of these components is abbreviate|omitted suitably.

In the control unit 92 in the first modification, the formula (1) set in the same manner as in the above embodiment is stored in advance. The control unit 92 controls the upstream injection system 60 instead of the standby time ΔT1 of the downstream injection system 50 as in the above embodiment, for example, as the standby time ΔT based on the formula (1). ) to calculate the waiting time (ΔT11). This waiting time ΔT11 is the time from when the downstream injection system 50 starts injection of the second fuel until the upstream injection system 60 starts injection, that is, the first injection pump 51 ) is the time from starting operation until the second infusion pump 61 starts operation. The control unit 92 determines the timing at which the upstream injection system 60 starts injection of the second fuel by the minute of the thus calculated waiting time ΔT11, and sets the timing at which the downstream injection system 50 starts the injection of the second fuel. The timing to start the injection is delayed.

Specifically, the control unit 92 controls the downstream injection system 50 at the timing T11 at which the current crank angle becomes the first crank angle R11 based on the detection result by the detection unit 91 . An electrical signal is input to the first control valve 55 of Thereby, the 1st injection pump 51 starts injection of the 2nd fuel to the 1st injection position P1 in the fuel path L. That is, the timing T11 corresponding to the first crank angle R11 is the first-layer injection start timing in the downstream injection system 50 . At this timing T11, as illustrated in FIG. 9, injection of the 2nd fuel 203 to the 1st injection position P1 among the fuel columns 201 in the fuel path L is started. With the start of the injection of the second fuel 203 into the first injection position P1, the first fuel located between the first injection position P1 and the second injection position P2 is It starts to be pushed back upstream in the flow direction beyond (P2). Thereby, the amount of fuel located between the first injection position P1 and the second injection position P2 starts to be adjusted to decrease.

In addition, in the period T0 from the end of the previous layer injection until the first injection start timing T1 is reached, as illustrated in FIG. 9 , the second fuel is injected into the fuel column 201 , there is not The amount of fuel in the fuel column 201 at this time corresponds to the above-described first fuel injection amount Qfa.

Next, the control unit 92 controls the injection of the second fuel by the upstream injection system 60 at a timing delayed from the first layer injection start timing T11 by the amount of the waiting time ΔT11 calculated as described above. start Specifically, the control unit 92 converts the waiting time ΔT11 of the upstream injection system 60 into a change amount ΔR of the crank angle based on the engine rotation speed and the elapsed time of the engine rotation. The control unit 92 calculates the second crank angle R12 by adding the obtained change amount ΔR of the crank angle and the first crank angle R11 at the first layer injection start timing T11. As shown in FIG. 8 , the control unit 92 sends an electrical signal to the second control valve 65 of the upstream injection system 60 at the timing T12 when the current crank angle becomes the second crank angle R12. is output, and this is set to an open state. When the second control valve 65 is opened, the operation of the first injection pump 51 is continued while the operation of the second injection pump 61 in the upstream injection system 60 is started. . That is, this timing T12 is the same as the "second layer injection start timing" at which the upstream injection system 60 starts injection of the second fuel. At this second layer injection start timing T12 , as shown in FIG. 9 , the second fuel 203 is continuously injected into the first injection position P1 in the fuel column 201 , and the second fuel 203 is continuously injected. Injection of the second fuel 202 to the second injection position P2 is started.

After that, the first injection pump 51 continues to inject the second fuel into the first injection position P1 for a period until the first control valve 55 is in the closed state. In parallel with this, the second injection pump 61 continues to inject the second fuel into the second injection position P2 for a period until the second control valve 65 is in the closed state.

As illustrated in FIGS. 8 and 9 , the period ΔT13 from the first crank angle R11 to the predetermined crank angle Ra (> R12) is the second in the first injection position P1. Injection of fuel 203 proceeds. In addition, during the period ΔT13, during the period ΔTa from the second crank angle R2 to the crank angle Ra, the second fuel 203 is injected at the first injection position P1. While this advances, injection of the 2nd fuel 202 in the 2nd injection position P2 advances. With the injection of the second fuel 203 in the first injection position P1, the first fuel located between the first injection position P1 and the second injection position P2 is a second injection It is pushed back to the upstream side in the flow direction beyond the second fuel 202 at the position P2. Thereby, the amount of the first fuel positioned between the first injection position P1 and the second injection position P2 is adjusted so as to decrease at the height of the period ?T13.

In addition, during this period (ΔT13), at the timing T13 corresponding to the predetermined third crank angle R13, the second fuel 203 at the first injection position P1 is transferred to the fuel column 201 is injected until it spreads across the width direction of At this time, as illustrated in FIG. 9 , the second fuel 203 in the first injection position P1 is the fuel column 201 in the fuel path L, the first injection position P1 . ) is divided into the most downstream fuel 201c located on the downstream side and the upstream side fuel 201e located on the upstream side from the first injection position P1. In this step, the total amount of the first fuel constituting the most downstream fuel 201c is determined. In addition, in the period from the third crank angle R13 to the predetermined fourth crank angle R14 (> R13), the second fuel 203 at the first injection position P1 is transferred to the fuel column ( While it is further injected in the state spread across the width direction of 201, the 2nd fuel 202 in the 2nd injection position P2 is injected continuously. In this step, the injection of the second fuel 203 at the first injection position P1 includes the first fuel located between the first injection position P1 and the second injection position P2, It is carried out while pushing back from the 2 injection|pouring position P2 to the upstream in the flow direction.

On the other hand, at the timing corresponding to the said crank angle Ra, it is inject|poured until the 2nd fuel 202 in the 2nd injection position P2 spreads over the width direction whole area of the fuel column 201. At this time, as for the 2nd fuel 202 in the 2nd injection position P2, the upstream fuel located in the upstream side of the fuel column 201 rather than the 2nd injection position P2 with the upstream fuel 201e. 201b, the second fuel 202 at the second injection position P2, and the injection interlayer fuel 201d sandwiched between the second fuel 203 at the first injection position P1 do. In this step, the fuel between the first injection position P1 and the second injection position P2 is the second injection position even if the injection of the second fuel 203 into the first injection position P1 proceeds. It is prevented from being pushed back to the upstream side in the flow direction beyond the second fuel 202 in (P2). Thereby, the adjustment of the amount of the first fuel located between the first injection position P1 and the second injection position P2 is finished, and the amount of the inter-injection fuel 201d, that is, the first fuel between the injection-layers. The amount of (= Qf2) is determined.

The timing corresponding to the crank angle Ra may be the same as the timing T14 at which the required amount of the second fuel 202 is injected at the second injection position P2, or a timing before this timing T14 Alternatively, the timing may be later than the timing T14. Which of these timings will be the timing corresponding to the crank angle Ra is determined by the waiting time ?T11 according to the engine load. In the example shown in FIG. 9, when the timing corresponding to the said crank angle Ra is the same timing as the timing T14 at the 4th crank angle R14.

Moreover, as illustrated in FIG. 9, the control part 92 in a 1st modified example sends the downstream injection system 50 to the timing T14 when the current crank angle became the 4th crank angle R14. A control signal is output to the 1st control valve 55 in this, and this is made into a closed state. Accordingly, the control unit 92 stops the operation of the first injection pump 51 in the downstream injection system 50 while continuing the operation of the second injection pump 61 . In this way, the first injection pump 51 ends the injection into the first injection position P1 in the fuel path L. That is, the timing T14 corresponding to the fourth crank angle R14 is the same as the "first-layer injection end timing" at which the downstream injection system 50 ends injection of the second fuel. On the other hand, the 2nd injection pump 61 continues injecting into the 2nd injection position P2 in the fuel path L. As shown in FIG. 9 , at the timing T14 corresponding to the fourth crank angle R14, the required amount of the second fuel 203 is injected into the first injection position P1.

Thereafter, as shown in FIG. 8 , the control unit 92 controls the upstream injection system 60 at a timing T15 at which the current crank angle becomes a predetermined fifth crank angle R15 (> R14). 2 A control signal is output to the control valve 65, and this is made into a closed state. Thereby, the 2nd injection pump 61 of the upstream injection system 60 stops operation. Then, the second injection pump 61 ends the injection into the second injection position P2 in the fuel path L. That is, the timing T15 corresponding to the fifth crank angle R15 is the same as the “second layer injection end timing” at which the upstream injection system 60 ends the injection of the second fuel.

As illustrated in FIG. 9 , in the period from the timing T14 corresponding to the fourth crank angle R14 to the timing T15 corresponding to the fifth crank angle R15, at the second injection position P2 In the state where the 2nd fuel 202 in has spread over the width direction whole area of the fuel column 201, it is inject|poured further. On the other hand, the injection of the second fuel 203 to the first injection position P1 has already been completed at the above-described timing T14. In this step, the injection of the second fuel 202 at the second injection position P2 is performed in the same manner as the period from the timing T13 to the timing T14 described above, and the second fuel 202 is ) is continued until the required amount of injection is reached. And at the timing T15 corresponding to the 5th crank angle R15, injection to the 2nd injection position P2 and the 1st injection position P1 is complete|finished. As a result, the downstream fuel layer F1, the downstream injection layer A1, the intermediate fuel layer F2, the upstream injection layer A2, and the upstream fuel layer F3 are sequentially arranged. A layered liquid 200 is formed in the fuel path L.

Here, in the first modification, the injection period (first injection period) of the second fuel by the downstream injection system 50 is the fourth crank at the timing T11 corresponding to the first crank angle R11. It is the period until the timing T14 corresponding to the angle R14. That is, the first injection period is a period obtained by adding the waiting time ΔT11 and the period ΔT12 illustrated in FIG. 8 . This first injection period is determined by the time required when injecting the required amount of the second fuel 203 into the first injection position P1 illustrated in FIG. 9 . That is, the fourth crank angle R14 corresponding to the first injection end timing (timing T14) in the downstream injection system 50 is the first crank angle R11 corresponding to the first injection start timing. It is calculated based on the time required for injection of the required amount of the second fuel 203 .

In addition, the injection period (second injection period) of the second fuel by the upstream injection system 60 corresponds to the fifth crank angle R15 at the timing T12 corresponding to the second crank angle R12. This is the period until the timing T15. This second injection period is determined by the time required when injecting the required amount of the second fuel 202 into the second injection position P2 illustrated in FIG. 9 . That is, the fifth crank angle R15 corresponding to the second-layer injection end timing (timing T15) in the upstream injection system 60 is the second crank angle R12 corresponding to the second-layer injection start timing. It is calculated based on the time required for injection of the required amount of the second fuel 202 .

In the first modification, the overlapping period of the injection period of the downstream injection system 50 (first injection period) and the injection period of the upstream injection system 60 (second injection period) is illustrated in FIG. 8 . As shown, it corresponds to the period ?T12 from the second crank angle R12 to the fourth crank angle R14. During this period ΔT12, the period ΔTa from the second crank angle R12 to the crank angle Ra is an intermediate fuel layer located between injection layers by injection from the downstream injection system 50 . It is a part of the period in which the first fuel is reduced in (F2). In addition, the waiting time ΔT11 from the first crank angle R11 to the second crank angle R12 is the remainder of the period in which the first fuel is reduced in the intermediate fuel layer F2. That is, these waiting time ?T11 and the reduction period ?T13 obtained by adding the period ?Ta are the total period during which the first fuel is reduced in the intermediate fuel layer F2. The second layer injection start timing by the upstream injection system 60 is set such that the weight reduction period ΔT13 decreases with an increase in the engine load, and the weight reduction period ΔT13 increases with the decrease of the engine load. It is controlled to a timing as slow as the waiting time (ΔT11) from the start timing of the second layer implantation. That is, this waiting time ?T11 decreases with an increase in the engine load, and increases with a decrease in the engine load. In addition, when this waiting time ΔT11 is a zero value (ΔT11 = 0), the second layer injection start timing by the upstream injection system 60 is the first layer injection start timing by the downstream injection system 50 . is controlled at the same time as

By controlling in this way, similarly to the above embodiment, the first fuel, the second fuel, the first fuel, the second fuel, and the first fuel are sequentially injected from the fuel injection valve 30 in a layered manner. As a result, combustion of the second fuel (alternative fuel) as the main fuel is promoted more reliably, and generation of combustion residues can be suppressed.

8 and 9 , at least a part of the first injection period by the downstream injection system 50 and the second injection period by the upstream injection system 60 overlap with each other on the downstream side, as illustrated in FIGS. 8 and 9 . The timing at which the injection system 50 and the upstream injection system 60 start injection of the second fuel, respectively, is controlled according to the engine load. Thereby, it becomes possible to control so that the ratio of the 1st fuel injection quantity Qfa which is determined according to the engine load and the fuel quantity Qf2 in the intermediate|middle fuel layer F2 does not become excessive or too small. Thereby, the operation of the engine 1 can be stabilized, and it becomes possible to ensure its performance.

(6) Modifications of the first fuel and the second fuel (second modification)

In the said embodiment and its 1st modification, although it was comprised so that a 1st fuel might function as a pilot fuel and a 2nd fuel function as a main fuel, the technique disclosed here is not limited to this structure.

Moreover, in the said embodiment and its 1st modification, it was comprised so that an alternative fuel was used as a 1st fuel and a fossil fuel was used as a 2nd fuel, but the technique disclosed here is not limited to this structure either. does not

For example, in a modification shown below (hereinafter, referred to as a "second modification"), the first fuel functions as a main fuel for generating the power of the engine 1, and the second fuel , it functions as a pilot fuel for igniting the main fuel. As the first fuel according to the second modification, ammonia as an alternative fuel can be used, and as the second fuel according to the modification, diesel fuel as a fossil fuel can be used. That is, similarly to the said embodiment and its 1st modification, the fossil fuel which concerns on a 2nd modification has low at least one of the pressure and temperature which leads to compression ignition compared with the alternative fuel which concerns on the same modification.

FIG. 10 is a diagram corresponding to FIG. 2 showing a second modification of the engine 1 (particularly, the fuel injection device 100 ), and FIG. 11 is a diagram corresponding to FIG. 3 in the second modification of the engine 1 . am. In the following description, the same name and code|symbol as the said embodiment are used about the component comprised similarly to the said embodiment. About those components, description is abbreviate|omitted suitably.

As illustrated in FIGS. 10 and 11 , the fuel injection device 100' according to the second modification can inject the alternative fuel as the first fuel and the fossil fuel as the second fuel in a layered manner. In this case, a carbon-free fuel (specifically, ammonia) can be used as an alternative fuel, while a diesel fuel can be used as a fossil fuel.

The fuel pump 41' according to the second modification is connected to a fuel tank (not shown) in which an alternative fuel as the first fuel is stored via a pipe or the like, and receives fuel from the fuel tank.

Moreover, the fuel injection device 100' which concerns on a 2nd modified example is equipped with the fossil fuel pump 71' instead of the alternative fuel supply pump 71. As shown in FIG. The fossil fuel pump 71' transfers the fossil fuel stored in a tank (not shown) for storing fossils as the second fuel to the first injection pump 51 through branch pipes 72a and 72b and the like. It is supplied to the second infusion pump 61 .

And the control part 92 which concerns on a 2nd modification is, among the fuel layers injected from the fuel injection valve 30, the fuel layer which consists of an alternative fuel as a 1st fuel, and the fuel layer which consists of a fossil fuel as a 2nd fuel. The injection systems 50 and 60 configured in the same manner as in the above embodiment are controlled so that both of them are two or more layers.

With this configuration, as illustrated in FIG. 11 , the fuel injection valve 30 is operated by the first fuel (ammonia as an alternative fuel) pressurized by the fuel pump 41 ′ and the downstream injection system 50 . Second fuel injected (diesel fuel as fossil fuel), first fuel pumped by the fuel pump 41' (ammonia as alternative fuel), and secondary fuel injected by upstream injection system 60 (fossil fuel) Diesel fuel as fuel) and the first fuel (ammonia as an alternative fuel) pressurized by the fuel pump 41 ′ are sequentially arranged, and the layered liquid is injected from the injection port 31 into the combustion chamber 17 . Thereby, combustion of the 1st fuel (alternative fuel) as a main fuel is accelerated|stimulated more reliably, and it becomes possible to suppress generation|occurrence|production of a combustion residue.

That is, by injecting the fuel as described above, as illustrated in FIG. 11 , the first fuel, the second fuel, the first fuel, the second fuel, and the first fuel are sequentially injected in a layered manner. In this case, combustion of the first fuel (alternative fuel) injected following the first second fuel (fossil fuel) is promoted by the first second fuel (fossil fuel) as illustrated in FIG. 11 . The first fuel (alternative fuel) used is divided into two, and the first fuel (alternative fuel) whose combustion is promoted by the second second fuel (fossil fuel) injected thereafter. The first fuel (alternative fuel) to be accelerated of combustion is divided into two, and the second fuel (fossil) divided into two in the same way as the first fuel (alternative fuel) is the combustion of each divided first fuel (alternative fuel). fuel) can be promoted. As a result, combustion of the first fuel (alternative fuel) is promoted more reliably, and it becomes possible to suppress generation of combustion residues.

Moreover, consumption of fossil fuels including diesel fuel can be suppressed by using alternative fuels, such as ammonia, as a main fuel. In particular, by suppressing the combustion residues of the fuel as in the second modification, more alternative fuels can be burned.

(7) Other embodiments

In the said embodiment and its 1st and 2nd modified example, the fossil fuel used as one of the 1st and 2nd fuel compared with the alternative fuel used as the other of the 1st and 2nd fuel the pressure and the pressure and Although at least one of the temperature was comprised low, it is not limited to this structure. At least one of the pressure and temperature leading to compression ignition can also use the low alternative fuel compared with a fossil fuel. For example, as another structural example, while using diesel fuel as a fossil fuel, methanol can be used as an alternative fuel. In this case, the fossil fuel becomes the main fuel and the alternative fuel serves as the pilot fuel, but the fossil fuel may be used as the first fuel and the alternative fuel as the second fuel (pattern C to be described later), and the alternative fuel is used as the first fuel and a fossil fuel may be used as the second fuel (pattern D to be described later). In either case, the other can be divided into two by one of the 1st and 2nd fuels, and both the fuel layer which consists of a 1st fuel and the fuel layer which consists of a 2nd fuel can be made into two or more layers. Thereby, it is possible to suppress combustion residues of the fuel.

Table 1 has shown the combination of the 1st and 2nd fuel in the said embodiment, a 1st modification, a 2nd modification, and another structural example. In Table 1, pattern A indicates the combination of fuels in the above-described embodiment and the first modification, pattern B indicates the combination of fuels in the second modification, and patterns C and D indicate, Both refer to the combination of fuels in other structural examples.

"Combustibility" in Table 1 has shown the easiness of ignition of 1st and 2nd fuel. This combustibility can be determined based on at least one of the pressure and temperature which reach compression ignition, for example. Combustibility is not an absolute index, but only a relative index when the first fuel and the second fuel are compared.

Specifically, in the pattern A, while using a fossil fuel (for example, diesel fuel) as a 1st fuel, an alternative fuel (for example, ammonia) will be used as a 2nd fuel. In the said embodiment corresponding to pattern A, compared with 2nd fuel, the combustibility of 1st fuel becomes favorable.

Moreover, in pattern B, unlike pattern A, while using an alternative fuel (for example, ammonia) as a 1st fuel, a fossil fuel (for example, diesel fuel) is used as a 2nd fuel. In the said 2nd modification corresponding to pattern B, unlike pattern A, compared with 1st fuel, the combustibility of 2nd fuel becomes favorable.

Moreover, in pattern C, while using fossil fuel (for example, diesel fuel) as a 1st fuel similarly to pattern A, an alternative fuel (for example, methanol) is used as a 2nd fuel. In the said other structural example corresponding to pattern C, unlike pattern A, compared with 1st fuel, the combustibility of 2nd fuel becomes favorable.

Moreover, in pattern D, while using an alternative fuel (for example, methanol) as a 1st fuel similarly to pattern B, a fossil fuel (for example, diesel fuel) is used as a 2nd fuel. In the said other structural example corresponding to the pattern D, unlike the pattern B, compared with the 2nd fuel, the combustibility of a 1st fuel becomes favorable.

The technique disclosed herein is applicable to all of these patterns A to D.

In addition, in the said embodiment and its 1st modification, when the downstream injection system 50 and the upstream injection system 60 control the timing of starting injection of a 2nd fuel, respectively, it calculates according to engine load. The crank angle was calculated from one waiting time (ΔT1, ΔT11), and the timing at which the calculated crank angle and the current crank angle by the detection unit 91 coincide was set as the injection start timing following the previous injection start timing, This indication is not limited to this. For example, the downstream injection system 50 and the upstream injection system 60 may be controlled based on the operating time of the engine 1, and in this case, the elapsed time from the previous injection start timing is applied to the engine load. The timing at which the following waiting time is reached may be a later injection start timing.

Moreover, although the fuel injection apparatus 100 provided with the three fuel injection valves 30 for every cylinder 16 was illustrated in embodiment mentioned above and 1st and 2nd modification, this indication is limited to this it is not going to be For example, the number of fuel injection valves 30 may be one, and it is good also as any two or more arbitrary numbers.

1 engine (ship diesel engine)
16 cylinder
17 combustion chamber
30 fuel injection valve
31 nozzle
32 first internal path (fuel path)
41 fuel pump
42 fuel injection pipe (fuel path)
42a branch pipe (fuel path)
50 Downstream Injection Line (1st Injection Line)
60 Upstream Injection Line (Second Injection Line)
92 control
100 fuel injector
200 layered liquid
A1 downstream injection layer (fuel layer composed of the second fuel injected by the first injection system)
A2 upstream injection layer (fuel layer composed of the second fuel injected by the second injection system)
F2 intermediate fuel layer (fuel layer consisting of the first fuel)
L fuel path
P1 first injection position
P2 2nd injection position
Qfa 1st fuel injection quantity (injection quantity per 1 time of 1st fuel injection)
Qf2 amount of intermediate fuel layer
ΔT1 latency
ΔT11 latency

Claims (7)

a cylinder partitioning the combustion chamber;
a fuel injection valve formed to face the combustion chamber and having an injection port for injecting fossil fuels and alternative fuels;
a fuel pump which pressurizes the 1st fuel which consists of one of the said fossil fuel and an alternative fuel toward the said fuel injection valve;
a fuel path from the fuel pump to the injection port;
an injection system for injecting a second fuel composed of the other of the fossil fuel and the alternative fuel to a predetermined position in the fuel path;
and a control unit for controlling the injection system,
The fuel injection valve injects the first fuel pressurized by the fuel pump and the second fuel injected by the injection system in a layered manner in a state in which they are alternately arranged,
The control unit controls the injection system such that, among the fuel layers injected from the fuel injection valve, both the fuel layer made of the first fuel and the fuel layer made of the second fuel are two or more,
The injection system is
a first injection system for injecting the second fuel into a predetermined first injection position in the fuel path;
a second injection system for injecting the second fuel into a second injection position upstream from the first injection position in the fuel path;
The fuel injection valve may include the first fuel supplied by pressure by the fuel pump, the second fuel injected by the first injection system, the first fuel supplied by pressure by the fuel pump, and the second injection system. Injecting a layered liquid including a fuel layer arranged in order of the second fuel injected by the fuel pump and the first fuel pumped by the fuel pump into the combustion chamber,
The control unit, according to the load of the marine diesel engine, so that the injection period by the first injection system and at least a part of the injection period by the second injection system overlap, the first injection system of the second fuel A marine diesel engine characterized by controlling a timing for starting injection and a timing for starting injection of the second fuel by the second injection system. The method of claim 1,
The control unit is located between a fuel layer composed of the second fuel injected by the first injection system and a fuel layer composed of the second fuel injected by the second injection system, and Timing at which the first injection system starts injecting the second fuel so that the amount of the formed fuel layer becomes a constant ratio with respect to the injection amount per one time of the first fuel; A marine diesel engine characterized by controlling the timing of starting injection of fuel. 3. The method of claim 1 or 2,
The control unit calculates a predetermined waiting time based on the load of the marine diesel engine, and sets a timing at which the first injection system starts injection of the second fuel by the calculated waiting time. A marine diesel engine, characterized in that the second injection system delays the timing of starting injection of the second fuel. 3. The method of claim 1 or 2,
The control unit calculates a predetermined waiting time based on the load of the marine diesel engine, and determines a timing at which the second injection system starts injection of the second fuel by the calculated waiting time. A marine diesel engine, characterized in that the first injection system delays the timing of starting injection of the second fuel. 3. The method of claim 1 or 2,
The control unit, irrespective of the load of the marine diesel engine, such that the ratio of the injection amount of the second fuel by the first injection system to the injection amount of the second fuel by the second injection system is constant, the second A marine diesel engine, characterized in that it controls the first injection system and the second injection system. delete delete

Images