CN117627829A

CN117627829A - Fuel injection system

Info

Publication number: CN117627829A
Application number: CN202310603551.6A
Authority: CN
Inventors: 大场启道; 伊藤和久
Original assignee: Japan Engine Corp
Current assignee: Japan Engine Corp
Priority date: 2022-08-24
Filing date: 2023-05-25
Publication date: 2024-03-01
Also published as: JP2024030317A; KR20240028283A

Abstract

The present invention provides a fuel injection system comprising an injection pump for injecting a substitute fuel such as ammonia into fossil fuel, wherein the injection pump can inject the same amount of the substitute fuel into a plurality of fuel injection valves even if individual differences exist when the substitute fuel such as ammonia has lower viscosity than water. At S3, the average ejection amount is calculated. Then, in S4, the pump rising amounts of the first injection pump unit (51 a), the second injection pump unit (51 b), and the third injection pump unit (51 c) are controlled so that the discharge amounts of the injection pump units (51 a, 51b, 51 c) reach the average discharge amount.

Description

Fuel injection system

Technical Field

The present invention relates to a fuel injection system including an injection pump for a marine engine or the like. And more particularly to a fuel injection system including an injection pump for injecting alternative fuel such as ammonia into fossil fuel.

Background

In recent years, it has been demanded to realize so-called zero emission in which the amount of carbon dioxide emitted is zero due to global warming or the like. Therefore, it is difficult to achieve zero emission in a conventional marine engine using fossil fuel such as heavy oil as fuel, and thus, a marine engine or the like in which both alternative fuel such as ammonia and fossil fuel such as heavy oil are combusted, that is, so-called "mixed combustion" is considered.

For example, the following patent document 1 discloses: in order to mix and burn fossil fuel and alternative fuel, a fuel injection valve is provided that injects fossil fuel and alternative fuel in layers, and fossil fuel and alternative fuel are injected from the fuel injection valve to mix and burn them in a combustion chamber.

In patent document 1, since fossil fuel and alternative fuel are injected in layers from the fuel injection valve 30, the fossil fuel and alternative fuel are pressurized and transported by the fuel pump 41 and the injection pump 51.

In this case, in the case of an engine including a plurality of cylinders, in order to stabilize the combustion state of each cylinder, it is necessary to match the amount of the substitute fuel supplied from the injection pump with the ratio of the fossil fuel in each fuel injection valve, and it is necessary to keep the amount of the substitute fuel equal in each fuel injection valve.

As an injection pump for maintaining the supply amount of the alternative fuel equal to each other in each fuel injection valve as described above, there is an injection pump 41 described in patent document 2 below. In the injection pump 41, the water piston portions 6a, 6b, 6c connected to one connecting portion 8 press the plurality of water discharge passages 2a, 2b, 2c connected to the respective fuel injection valves, so that the amounts of water discharged from the respective water discharge passages 2a, 2b, 2c are equalized in the respective fuel injection valves.

Consider: by using the structure of this injection pump 41 in the injection pump of the alternative fuel, the supply amount of the alternative fuel is thereby kept equal in each fuel injection valve.

Patent document 1: japanese laid-open patent publication No. 2020-180567

Patent document 2: japanese laid-open patent publication No. 2020-60110

Disclosure of Invention

Technical problem to be solved by the invention

It is believed that, as described in patent document 2, since the plurality of ejection passages are pressed by the plurality of piston portions connected to one connecting portion, the rising amounts (pressing amounts) of the piston portions are uniform, and the amounts of the substitute fuel ejected from the ejection passages can be kept equal.

However, since the viscosity of ammonia, which is a representative alternative fuel, is about 1/10 of the viscosity of water, which is about 0.115mpa·s (millipascal seconds) at 20 ℃, even if the ammonia is pushed by a plurality of piston portions connected to one connecting portion as in patent document 2, the ammonia leaks (leaks) from the gap between the piston portion and the ejection passage (piston sliding portion), and there is a problem that an equal amount cannot be ejected. That is, since the width of the gap between the piston portion and the discharge passage (piston sliding portion) is different for each gap, the amount of ammonia leakage is different depending on the individual difference in width of each gap, and an equal amount cannot be discharged.

Of course, it is also contemplated that: for leakage from the gap between such a piston portion and the discharge passage (piston sliding portion), sealing members, ring members, or the like are used to improve sealability to prevent leakage.

However, if such a sealing member, a ring member, or the like is used to improve the sealing performance, the sliding resistance between the piston portion and the discharge passage (piston sliding portion) increases, and the upward movement of the piston portion is hindered, so that there is a problem that the piston portion cannot smoothly rise and the substitute fuel cannot be sufficiently discharged.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel injection system including an injection pump for injecting a substitute fuel such as ammonia into fossil fuel, wherein the injection pump can inject the same amount of the substitute fuel into a plurality of fuel injection valves even if there is an individual difference in the width of a gap between a piston portion and an injection passage (piston sliding portion) when the substitute fuel such as ammonia has a viscosity lower than that of water is injected.

Technical solution for solving the technical problems

In order to achieve the object, the present invention relates to a fuel injection system including an injection pump for injecting an alternative fuel such as ammonia into fossil fuel, the fuel injection system characterized in that: the structure is as follows: injection pump units are set for the respective fuel injection valves, and injection amounts from the respective injection pump units are controlled so that injection amounts from the respective injection pump units corresponding to the respective fuel injection valves provided in the same cylinder are equal to each other.

In particular, the invention of the first aspect relates to a fuel injection system for a multi-cylinder engine in which fossil fuel and alternative fuel are mixed and combusted in a combustion chamber, the fuel injection system including an injection pump that supplies alternative fuel among the fossil fuel and the alternative fuel to a fuel injection valve, the fuel injection system being characterized in that:

the injection pump includes a plurality of injection pump portions configured to inject the alternative fuel into the respective fuel injection valves, and the fuel injection system includes injection amount control means for controlling the injection amount of the alternative fuel by the injection pump portions so that the injection amount of the alternative fuel by the injection pump portions is equal to the injection amount of the alternative fuel by the other injection pump portions that are provided to the fuel injection valves of the same cylinder.

According to this configuration, a plurality of injection pump units are provided for injecting the alternative fuel into each fuel injection valve, and the injection amount control means controls the injection amount of each of the injection pump units so that the injection amount of the alternative fuel is equal to the injection amount of the other injection pump units injecting the alternative fuel into the fuel injection valves provided in the same cylinder.

Therefore, since the injection amounts to be injected from the injection pump portions to the fuel injection valves are controlled individually, even when there is a large deviation in the leakage amount due to the individual difference of the injection pump portions when the substitute fuel having a low viscosity such as ammonia is injected, the injection amounts to be injected from the injection pump portions to the fuel injection valves can be made equal between the injection pump portions that inject the substitute fuel to the fuel injection valves provided in the same cylinder.

Here, the "Alternative Fuel" refers to a fluid Fuel having a lower viscosity than water, such as ammonia or methanol, in a Fuel (Alternative Fuel) that replaces petroleum.

The invention of the second aspect is characterized in that: the injection amount control unit includes: an ejection amount measuring unit that measures an ejection amount of the substitute fuel from each injection pump unit that injects the substitute fuel to a fuel injection valve provided in the same cylinder; an average injection amount calculation unit that calculates an average injection amount of all injection pump units that inject the substitute fuel into the fuel injection valves provided in the same cylinder, based on the injection amount of the substitute fuel measured by the injection amount measurement unit; and a rise control means for controlling the rise of each of the injection pump units so that the discharge amount of each of the injection pump units reaches the average discharge amount, based on the average discharge amount calculated by the average discharge amount calculation means.

According to this configuration, the ejection amount from each injection pump portion is measured by the ejection amount measuring means, and each injection pump portion injects the substitute fuel to the fuel injection valve provided in the same cylinder; calculating an average ejection amount according to the ejection amount by an average ejection amount calculating unit; the rising amount of each injection pump portion is controlled by a rising amount control means so as to achieve the average discharge amount.

Accordingly, the rising amounts of the respective injection pump units are controlled based on the average discharge amounts, and therefore, the respective injection pump units discharge the alternative fuel with different rising amounts.

Thus, even if the leak amount differs between the injection pump portions, by controlling the injection pump portions with different rising amounts, the same amount of substitute fuel is injected from all the injection pump portions that inject the substitute fuel to the fuel injection valves provided in the same cylinder to the fuel injection valves.

The invention of the third aspect is characterized in that: the injection amount control unit includes: a leakage amount measurement unit that measures a leakage amount of the substitute fuel from each injection pump unit that injects the substitute fuel to a fuel injection valve provided in the same cylinder; a discharge amount estimating unit that calculates a discharge amount of the alternative fuel measured by the discharge amount measuring unit subtracted from a stroke volume of each of the injection pump units, and uses the obtained value as an estimated discharge amount of each of the injection pump units; an average estimated injection amount calculation means for calculating an average estimated injection amount of all injection pump units that inject the substitute fuel into the fuel injection valves provided in the same cylinder, based on the estimated injection amount of the substitute fuel calculated by the injection amount estimation means; and a rise control means for controlling the rise of each injection pump unit so that the discharge amount of each injection pump unit reaches the average estimated discharge amount, based on the average estimated discharge amount calculated by the average estimated discharge amount calculation means.

According to this configuration, the leakage amount of the substitute fuel from each injection pump portion is measured by the leakage amount measuring means, and each injection pump portion injects the substitute fuel to the fuel injection valve provided in the same cylinder; calculating a leakage amount of the substitute fuel subtracted from a stroke volume of each injection pump portion by an injection amount estimating means, and using the obtained value as an estimated injection amount of each injection pump portion; calculating an average estimated ejection amount of all the injection pump units based on the estimated ejection amount by an average estimated ejection amount calculation means; the rise control means controls the rise of each injection pump unit so that the discharge amount of each injection pump unit reaches the average estimated discharge amount.

Therefore, the rising amounts of the respective injection pump units are controlled based on the average estimated injection amount, and therefore, the respective injection pump units can inject the alternative fuel with different rising amounts. That is, it is considered that the different leak amounts of the respective injection pump units mean different discharge amounts, and therefore, even when the flow rate of the substitute fuel actually discharged cannot be measured, the leak amount is measured to control the rising amount of the respective injection pumps, and the same amount of the substitute fuel is supplied to the respective fuel injection valves.

Thus, even if the leak amount is different in each injection pump portion, by controlling each injection pump portion with a different rise amount, the same amount of substitute fuel can be supplied from all injection pump portions that inject the substitute fuel to the fuel injection valves provided in the same cylinder to the fuel injection valves.

The invention of the fourth aspect is characterized in that: the injection amount control unit includes: a rising speed measuring unit that measures a rising speed of each injection pump unit that injects the substitute fuel into a fuel injection valve provided in the same cylinder; a discharge amount estimation unit that calculates an estimated discharge amount of each injection pump unit based on the rise rate measured by the rise rate measurement unit; an average estimated injection amount calculation means for calculating an average estimated injection amount of all injection pump units that inject the substitute fuel into the fuel injection valves provided in the same cylinder, based on the estimated injection amount of the substitute fuel calculated by the injection amount estimation means; and a rise control means for controlling the rise of each injection pump unit so that the discharge amount of each injection pump unit reaches the average estimated discharge amount, based on the average estimated discharge amount calculated by the average estimated discharge amount calculation means.

According to this configuration, the rising speed measuring means measures the rising speed of each injection pump portion for injecting the substitute fuel into the fuel injection valve provided in the same cylinder; calculating an estimated ejection amount of each injection pump unit based on the rising speed by an ejection amount estimation unit; calculating an average estimated ejection amount of all the injection pump sections from the estimated ejection amount by an average estimated ejection amount calculation means; the rise control means controls the rise of each injection pump unit so that the discharge amount of each injection pump unit reaches the average estimated discharge amount.

Therefore, the rising amounts of the respective injection pump units are controlled based on the average estimated injection amount, and therefore, the respective injection pump units can inject the alternative fuel with different rising amounts. That is, it is considered that the different rising speeds of the respective injection pump units mean different injection amounts, and therefore, even when the flow rate of the substitute fuel actually injected cannot be measured, the rising speeds are measured to control the rising amounts of the respective injection pumps, and the same amount of the substitute fuel is supplied to the respective fuel injection valves.

By measuring the rising speed of the injection pump sections, the discharge amounts of the injection pump sections are thereby indirectly estimated, and the discharge amounts of all the injection pump sections for injecting the substitute fuel into the fuel injection valves provided in the same cylinder can be kept approximately the same.

The invention of the fifth aspect is characterized in that: the injection amount control unit includes: an internal pressure measurement unit that measures an internal pressure when each injection pump unit that injects the substitute fuel into a fuel injection valve provided in the same cylinder rises; a discharge amount estimation unit that calculates an estimated discharge amount of each of the injection pump units based on the internal pressure measured by the internal pressure measurement unit; an average estimated injection amount calculation means for calculating an average estimated injection amount of all injection pump units that inject the substitute fuel into the fuel injection valves provided in the same cylinder, based on the estimated injection amount of the substitute fuel calculated by the injection amount estimation means; and a rise control means for controlling the rise of each injection pump unit so that the discharge amount of each injection pump unit reaches the average estimated discharge amount, based on the average estimated discharge amount calculated by the average estimated discharge amount calculation means.

According to this configuration, the internal pressure at the time of rising of each injection pump portion for injecting the substitute fuel into the fuel injection valve provided in the same cylinder is measured by the internal pressure measurement means; calculating an estimated ejection amount of each injection pump unit from the measured internal pressure by an ejection amount estimation means; calculating an average estimated ejection amount of all the injection pump units based on the estimated ejection amount by an average estimated ejection amount calculation means; the rise control means controls the rise of each injection pump unit so that the discharge amount of each injection pump unit reaches the average estimated discharge amount.

Therefore, the rising amounts of the respective injection pump units are controlled based on the average estimated injection amount, and therefore, the respective injection pump units can inject the alternative fuel with different rising amounts. That is, it is considered that the difference in the internal pressure at the time of rising of each injection pump unit means that the discharge amount is different, and therefore, even when the flow rate of the substitute fuel actually discharged cannot be measured, the internal pressure at the time of rising is measured to control the rising amount of each injection pump unit, and the same amount of the substitute fuel is supplied to each fuel injection valve.

By measuring the internal pressure at the time of rising of the injection pump sections, the discharge amounts of the injection pump sections are thereby indirectly estimated, and the discharge amounts of all the injection pump sections for injecting the substitute fuel into the fuel injection valves provided in the same cylinder can be kept approximately the same.

Effects of the invention

As described above, according to the present invention, since the injection amounts to be injected from the injection pump portions to the fuel injection valves are controlled individually, even when there is a large deviation in the leakage amount due to the difference in the width of the gap between the piston portion and the discharge passage (piston sliding portion) at the time of injecting the substitute fuel having a low viscosity such as ammonia, the amounts of the substitute fuel to be supplied from the injection pump portions to the fuel injection valves provided in the same cylinder can be made equal.

In this way, in the fuel injection system including the injection pump for injecting the alternative fuel such as ammonia into the fossil fuel, even if there is an individual difference in the width of the gap between the piston portion and the injection passage (piston sliding portion) when the alternative fuel such as ammonia having a lower viscosity than water is injected, the same amount of alternative fuel can be injected into the plurality of fuel injection valves.

Drawings

Fig. 1 is a schematic diagram showing the overall structure of a marine engine according to a first embodiment of the present invention;

FIG. 2 is a system diagram showing a system configuration of a fuel injection device;

FIG. 3 is a detailed longitudinal cross-sectional view showing a combustion chamber of a marine engine;

fig. 4 is a longitudinal sectional view showing a detailed construction of the first injection pump part of the first embodiment;

fig. 5 (a) is a diagram showing a case when the first injection pump portion is ejecting, and fig. 5 (b) is a diagram showing a case when the first injection pump portion is filled with fuel;

fig. 6 is a control flow chart according to the first embodiment;

fig. 7 is a longitudinal sectional view showing a detailed construction of the first injection pump part of the second embodiment;

fig. 8 is a control flow chart according to a second embodiment;

fig. 9 is a longitudinal sectional view showing a detailed construction of a first injection pump part of the third embodiment;

Fig. 10 is a control flow chart according to a third embodiment;

fig. 11 is a longitudinal sectional view showing a detailed construction of a first injection pump part of the fourth embodiment;

fig. 12 is a control flow chart according to a fourth embodiment.

Symbol description-

1-a marine engine; 10-cylinder; 17-combustion chamber; 30-a fuel injection valve; 51-an injection pump; 51 a-a first infusion pump section; 51 b-a second infusion pump section; 51 c-a third injection pump section; 92-a control part; 100-a fuel injection system; 113-a flow meter; 122-leakage measurer; 130-an ascent speed measurer; 140-plunger internal pressure measurer.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following preferred embodiments are merely examples of the present invention and are not intended to limit the present invention, its objects of application, or its uses.

(first embodiment)

Fig. 1 is a schematic diagram showing the overall structure of a marine engine, fig. 2 is a system diagram showing the system structure of a fuel injection device, fig. 3 is a detailed longitudinal sectional view showing the combustion chamber of the marine engine, and fig. 4 is a longitudinal sectional view showing the detailed construction of an injection pump. With reference to the above-described drawings, a brief description will be given first of all of the marine engine 1. Hereinafter, the marine engine 1 will be simply referred to as "engine 1".

The engine 1 is an in-line multi-cylinder marine engine including a plurality of cylinders 16. The engine 1 is configured as a two-cycle engine employing a uniflow scavenging system, and the engine 1 is mounted on a large-sized ship such as a mail wheel, a container ship, or an automobile carrier.

The engine 1 mounted on the ship serves as a main engine for propelling the ship. That is, the output shaft of the engine 1 is coupled to a propeller (not shown) of a ship via a propeller shaft (not shown). The structure is as follows: by operating the engine 1, the output of the engine 1 is transmitted to the propeller, thereby propelling the ship.

In particular, in order to achieve a longer stroke of the engine 1 according to the present embodiment, the engine 1 according to the present embodiment is configured as a so-called crosshead internal combustion engine. That is, in the engine 1, a piston rod 22 supporting the piston 21 from below and a connecting rod 24 connected to the crankshaft 23 are connected by a cross head 25.

Further, the engine 1 includes: a lower housing 11, a frame 12 provided on the housing 11, and a cylinder jacket (cylinder jacket) 13 provided on the frame 12. The housing 11, the frame 12, and the cylinder water jacket 13 are fastened by a plurality of tie bolts (tie bolts) B … … and nuts extending in the up-down direction. Further, the engine 1 includes a cylinder 16 provided in the cylinder water jacket 13, a piston 21 provided in the cylinder 16, and an output shaft (e.g., a crankshaft 23) that rotates in conjunction with the reciprocating motion of the piston 21.

The housing 11 constitutes a so-called crankcase of the engine 1, and the housing 11 houses a crankshaft 23 and a bearing 26 for rotatably supporting the crankshaft 23. The lower end of the connecting rod 24 is coupled to the crankshaft 23 via a crank 27.

The frame 12 accommodates a pair of guide plates 28, a link 24, and a cross head 25. Wherein the pair of guide plates 28, 28 are constituted by a pair of plate-like members provided in the piston axial direction, and are arranged with a space therebetween in the width direction of the engine 1 (the left-right direction of the paper surface of fig. 1). The connecting rod 24 is disposed between a pair of guide plates 28, 28 in a state where its lower end portion is coupled to the crankshaft 23. The upper end of the link 24 is connected to the lower end of the piston rod 22 via a cross head 25.

Specifically, the crosshead 25 is arranged between a pair of guide plates 28, and slides in the up-down direction along each guide plate 28, 28. That is, the pair of guide plates 28, 28 is configured to guide the sliding of the crosshead 25. The crosshead 25 is connected to the piston rod 22 and the connecting rod 24 via a crosshead pin 29. The cross pin 29 is connected to the piston rod 22 to move up and down integrally, and on the other hand, the cross pin 29 is connected to the link 24 to rotate the link 24 with the upper end portion of the link 24 as a fulcrum.

A cylinder jacket 14 as an inner cylinder is disposed in the cylinder water jacket 13. Inside the cylinder liner 14, the above-described piston 21 is disposed. The piston 21 reciprocates in the up-down direction along the inner wall of the cylinder liner 14. Further, a cylinder head 15 is fixed to an upper portion of the cylinder liner 14. The cylinder head 15 constitutes a cylinder 16 together with the cylinder liner 14.

Further, the cylinder head 15 is provided with an exhaust valve 18 that operates by an exhaust valve device (not shown in fig. 1). The exhaust valve 18 delimits a combustion chamber 17 together with the cylinder 16 and the top surface of the piston 21, wherein the cylinder 16 is formed by the cylinder liner 14 and the cylinder head 15. 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 (not shown) communicating with the combustion chamber 17, and the exhaust valve 18 is configured to open and close the exhaust port.

Further, the cylinder head 15 defines a top surface of the combustion chamber 17. On the top surface is provided a fuel injection valve 30.

As shown in fig. 3, the fuel injection valve 30 is provided in a posture as in a chamber facing the combustion chamber 17, and the fuel injection valve 30 has an injection port 31 that injects fossil fuel and alternative fuel. In fig. 3, only one fuel injection valve 30 is shown, however, three fuel injection valves 30 are provided in this embodiment.

Specifically, the fuel injection valves 30 are arranged in a posture in which the injection ports 31 face the inside of the combustion chamber 17, and the fuel injection valves 30 are configured to inject fuel in layers in a state in which fossil fuel and alternative fuel are alternately arranged.

Here, the alternative fuel functions as a main fuel that generates power of the engine 1, and the fossil fuel functions as a pilot fuel for igniting the main fuel. As the fossil fuel of the present embodiment, diesel fuel (so-called "heavy oil") is used, and ammonia is used as the substitute fuel.

The fuel injection system 100 for supplying fuel to the fuel injection valve 30 will be described later with reference to fig. 2.

In this way, the fuel injection valve 30 injects fossil fuel and alternative fuel into the combustion chamber 17, and burns both in the combustion chamber 17. The case of burning the fossil fuel and the alternative fuel is referred to as "mixed combustion". Details of the "mixed combustion" will be described later.

By this combustion, the piston 21 shown in fig. 1 reciprocates in the up-down direction. At this time, if the exhaust valve 18 is operated to open the combustion chamber 17, the exhaust gas generated by combustion is pressed into the exhaust pipe 19, and the scavenging air is introduced into the combustion chamber 17 from a scavenging port, not shown, provided below.

Further, if the piston 21 reciprocates due to the combustion, the piston rod 22 reciprocates in the up-down direction together with the piston 21. Thereby, the crosshead 25 coupled to the piston rod 22 reciprocates in the up-down direction. The cross head 25 is configured to allow the link 24 to rotate, and the link 24 is rotated about a connection portion with the cross head 25 as a fulcrum. A crank 27 connected to the lower end portion of the connecting rod 24 performs a crank motion, 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 a rotational motion, and rotates the propeller of the ship together with the propeller shaft. Thereby propelling the vessel.

Next, a fuel injection system 100 that supplies fuel to the fuel injection valve 30 will be described with reference to fig. 2.

The fuel injection system 100 includes a fuel pump 41 and an injection pump 51, the fuel pump 41 pressurizes and delivers fossil fuel to the fuel injection valve 30, and the injection pump 51 injects alternative fuel into a path for pressurizing and delivering fossil fuel. The injection pump 51 is constituted by three injection pump portions, namely, a first injection pump portion 51a, a second injection pump portion 51b, and a third injection pump portion 51c, corresponding to the three fuel injection valves 30 … ….

As shown in fig. 1, the fuel pump 41 and the injection pump portions 51a, 51b, and 51c are disposed near the cylinder 16, and are connected to the fuel injection valve 30 … … via the first internal path 32, the fuel injection pipe 42, the second internal path 33, and the injection pipes 52a, 52b, and 52c, respectively.

The fuel pump 41 is connected to the fuel injection valve 30 via a fossil fuel path L from the fuel pump 41 to the injection port 31, and the fuel pump 41 pressurizes and delivers fossil fuel toward the fuel injection valve 30. The fossil fuel path L is constituted by the first internal path 32 and the fuel injection pipe 42 (including a branch pipe 42a and the like described later), and is constituted as a path connecting the fuel pump 41 and the injection port 31.

The injection pump parts 51a, 51b, 51c are connected to the fossil fuel path L via the second internal path 33 and the injection pipes 52a, 52b, 52c, and the injection pump parts 51a, 51b, 51c are configured to inject the substitute fuel into the fossil fuel path L.

By configuring as described above, the fuel injection valve 30 can inject the fossil fuel pressurized and transported by the fuel pump 41 and the alternative fuel injected from the injection pump units 51a, 51b, 51c into the combustion chamber 17 in layers.

In the engine of the present embodiment, three fuel injection valves 30 and … … are provided in each cylinder. Therefore, in order to supply fossil fuel to each fuel injection valve 30 … …, the fuel injection pipe 42 is branched into three branched pipes (i.e., branched pipe 42a, branched pipe 42b, and branched pipe 42 c) via the branching portion 43.

The control unit 92 controls the fuel pump 41 for pressurizing and transporting the fossil fuel and the injection pump units 51a, 51b, and 51c for injecting the alternative fuel. Specifically, the fuel control valve 45 and the injection control valves 55a, 55b, 55c are controlled in response to control signals sent from the control unit 92, and the operations of the fuel pump 41 and the injection pump units 51a, 51b, 51c are controlled.

The control unit 92 is connected to a detection unit 91 that detects various signals such as a crank angle of the engine 1, and the control unit 92 is configured to: the fuel pump 41 and the injection pump sections 51a, 51b, and 51c are controlled based on various signals detected by the detection section 91. The broken line in fig. 2 indicates an electrical connection.

The fuel pump 41 is configured to: a fuel tank (not shown) storing fossil fuel is connected to the fuel tank through a pipe or the like (not shown), and fossil fuel is received from the fuel tank.

On the other hand, the constitution is as follows: the alternative fuel supply pump 71 for supplying the alternative fuel is connected to the injection pump units 51a, 51b, and 51c through the supply pipe 72, and the alternative fuel is supplied from the alternative fuel supply pump 71. The alternative fuel supply pump 71 is also configured to: also, the fuel tank is connected to a substitute fuel tank (not shown) storing a substitute fuel through a pipe or the like (not shown), and receives the substitute fuel from the substitute fuel tank.

The fuel pump 41 and the injection pump portions 51a, 51b, and 51c are connected to an accumulator 81. The accumulator 81 accumulates hydraulic oil for operating the fuel pump 41 and the injection pump units 51a, 51b, and 51c, respectively. The accumulator 81 is configured to: is connected to a high-pressure pump 82, and stores hydraulic oil fed under pressure from the high-pressure pump 82 and accumulates the hydraulic oil.

In the alternative fuel paths (the supply pipe 72, the injection pipes 52a, 52b, 52c, and the second internal path 33) into which the alternative fuel is injected, check valves Cv … … are provided in the respective paths (the supply pipe 72, the injection pipes 52a, 52b, 52c, and the second internal path 33) so as to prevent backflow of the alternative fuel.

With the fuel injection system 100 configured as described above, in the engine 1 of the present embodiment, the control unit 92 injects fossil fuel and alternative fuel from the fuel injection valve 30 … … into the combustion chamber 17, and thus mixed combustion occurs in the combustion chamber 17.

Next, a detailed structure of the injection pump according to the present embodiment will be described with reference to fig. 4. As described above, the injection pump of the present embodiment is constituted by three of the first injection pump portion 51a, the second injection pump portion 51b, and the third injection pump portion 51c, but in fig. 4, a longitudinal cross-sectional view of the first injection pump portion 51a is shown as a representative.

The first injection pump section 51a includes: a cylindrical casing 101 having a hollow interior; a hydraulic piston 102 provided at a lower portion of the inside of the housing 101 so as to move in an axial direction (up-down direction); a plunger 103 provided at an upper portion of the hydraulic piston 102 so as to move integrally with the hydraulic piston 102 in the axial direction; a fuel filling chamber 104 provided at an upper portion of the plunger 103 and capable of filling the internal space with a substitute fuel; an upper fixing plug 105 fixed to an upper portion of the housing 101; a lower fixing plug 106 fixed to the lower part of the housing 101 and guiding the hydraulic piston 102 in the axial direction on the inner peripheral surface thereof; an inner cylinder member 107 located on the outer peripheral side of the plunger 103 and fixed to the housing 101; a plunger spring 108 located on the outer peripheral side of the inner tube member 107 and applying a force to the plunger 103 toward the axially lower side; and a sleeve member 109 for supporting the plunger spring 108 and locking the plunger spring 108 to the plunger 103.

The upper stationary plug 105 is formed with a fuel inlet 110 penetrating from the radially outer side to the radially inner side, and the upper stationary plug 105 is configured to: the substitute fuel is supplied to the fuel filling chamber 104 therebelow. Further, an ejection port 112 including a check valve 111 is provided axially upward, and is configured to: the substitute fuel in the fuel filling chamber 104 is discharged from the discharge port 112 to the outside. A flow meter 113 is provided in the injection pipe 52a above the discharge port 112, and the flow meter 113 measures the flow rate of the discharged secondary fuel.

The operation of the first injection pump unit 51a configured as described above will be described with reference to fig. 5 (a) and 5 (b). Fig. 5 (a) is a diagram showing a case where the first injection pump portion 51a ejects the alternative fuel, and fig. 5 (b) is a diagram showing a case where the first injection pump portion 51a fills the alternative fuel.

First, as shown in fig. 5 (a), when the control unit 92 opens the injection control valve 55a at the time of discharging the alternative fuel, the hydraulic oil pressure acts on the hydraulic piston 102 as shown by the solid arrow, and the hydraulic piston 102 is pushed upward. Along with the rise of the hydraulic piston 102, the plunger 103 also rises as indicated by an arrow.

In this way, the discharge pressure acts on the substitute fuel filled in the fuel filling chamber 104 from the plunger 103, and the substitute fuel is discharged to the outside from the discharge port 112 against the check valve 111.

The substitute fuel thus discharged is supplied to the fuel injection valve 30 via the injection pipe 52 a.

On the other hand, as shown in fig. 5 (b), when the substitute fuel is filled, the control unit 92 closes the injection control valve 55a, and the hydraulic pressure is not allowed to act as indicated by the broken-line arrow. Thus, the hydraulic piston 102 and the plunger 103 are lowered as indicated by the arrow by the biasing force of the plunger spring 108. If the plunger 103 is lowered as described above, the fuel filling chamber 104 in the upper part thereof expands to generate negative pressure. Thus, due to the negative pressure, the alternative fuel is drawn into the fuel plenum 104 from the fuel inlet 110.

As described above, the first injection pump portion 51a operates, and thereby the substitute fuel is injected from the first injection pump portion 51a to the fuel injection valve 30. The other second injection pump portion 51b and the third injection pump portion 51c also operate similarly, and the substitute fuel is injected into the fuel injection valve 30.

However, in order to stabilize the combustion state in the same cylinder, it is necessary to match the amount of the substitute fuel supplied from these injection pump portions 51a, 51b, 51c with the ratio of the fossil fuel in each fuel injection valve 30 … … of the same cylinder, and it is necessary to maintain the amount of the substitute fuel supplied from these injection pump portions 51a, 51b, 51c at the same amount in each fuel injection valve 30.

However, the viscosity of the alternative fuel, ammonia, is 0.115 mPas at 20℃and is only about 1/10 of the viscosity of water, 1.01 mPas. Therefore, the ammonia, which is the alternative fuel, leaks (leaks) to the hydraulic piston 102 side through the gap between the plunger 103 and the inner cylinder member 107.

The amount of leakage is determined by the individual differences of the injection pump parts 51a, 51b, 51c, and therefore, the amount of leakage differs between the injection pump parts 51a, 51b, 51 c. That is, the width of the gap between the plunger 103 and the inner tube member 107 varies from one injection pump portion 51a, 51b, 51c to another due to this individual difference, and thus the leakage amount varies. Therefore, if the rising amount of the hydraulic piston 102 or the like is made uniform, there is a problem that the discharge amounts of the respective injection pump portions 51a, 51b, 51c are deviated from each other among the respective injection pump portions 51a, 51b, 51 c.

In this embodiment, the constitution is: a flow meter 113 is provided, and the discharge amount of the injection pump 51 is controlled based on the measurement result of the flow meter 113, wherein the flow meter 113 measures the flow rate of the discharged substitute fuel.

Next, control of the injection pump 51 according to the present embodiment will be described with reference to a control flowchart shown in fig. 6.

First, at S1, the control unit 92 reads various information. Various information required for controlling the engine, such as the position of the ship, the operating state of the ship, and further the steering information of the operator, is read from the detection unit 91 based on the GPS signal or the like.

Next, in S2, the discharge amounts of the respective injection pump units 51a, 51b, 51c are measured by the flowmeter 113.

Then, at S3, the average ejection amount is calculated by the control unit 92 based on the ejection amount. Specifically, the total of the discharge amount of the first injection pump portion 51a, the discharge amount of the second injection pump portion 51b, and the discharge amount of the third injection pump portion 51c is calculated and divided by 3, and the obtained value is used as the average discharge amount.

Then, at S4, the pump-up amounts of the first, second, and third injection pump units 51a, 51b, and 51c are controlled so that the discharge amounts of the injection pump units 51a, 51b, and 51c reach the average discharge amount.

Then, the process proceeds to return in preparation for the next control cycle.

As described above, the rising amounts of the respective injection pump units 51a, 51b, and 51c are controlled so that the discharge amounts of all the injection pump units are equal. That is, the injection pump unit having a small discharge amount is controlled so that the rise amount increases, and the injection pump unit having a large discharge amount is controlled so that the rise amount decreases.

Accordingly, since the same amount of the substitute fuel is discharged from all of the injection pump portions 51a, 51b, and 51c and supplied to the fuel injection valves 30 and … …, a stable mixed combustion state is obtained in the combustion chamber 17 of the same cylinder of the engine 1, and the engine 1 is operated.

As described above, the fuel injection system 100 according to the present embodiment is used in the multi-cylinder engine 1 in which the fossil fuel and the alternative fuel are mixed and burned in the combustion chamber 17 … …, and includes the injection pump 51 for supplying the alternative fuel to the fuel injection valve, the injection pump 51 includes the plurality of injection pump portions 51a, 51b, and 51c, the plurality of injection pump portions 51a, 51b, and 51c are set so as to inject the alternative fuel into the respective fuel injection valves 30 … …, and the fuel injection system 100 includes the control portion 92, and the control portion 92 controls such that: the injection amount of the alternative fuel in each of the injection pump units 51a, 51b, and 51c is equal to the injection amount of the alternative fuel in the other injection pump units that inject the alternative fuel into the fuel injection valve 30 … … provided in the same cylinder.

Thereby, the control unit 92 controls: the injection amount of the alternative fuel in each of the injection pump units 51a, 51b, and 51c is equal to the injection amount of the alternative fuel in the other injection pump units that inject the alternative fuel into the fuel injection valve 30 … … provided in the same cylinder.

Therefore, since the injection amounts of the respective injection pump portions 51a, 51b, and 51c into the respective fuel injection valves 30 … … are controlled, even when there is a large variation in the leakage amount due to the individual difference of the respective injection pump portions 51a, 51b, and 51c when the substitute fuel having a low viscosity such as ammonia is injected, the injection amounts of the respective injection pump portions 51a, 51b, and 51c into the fuel injection valves 30 … … can be made equal between the injection pump portions 51a, 51b, and 51c that inject the substitute fuel into the fuel injection valves 30 … … provided in the same cylinder.

In this way, in the fuel injection system 100 including the injection pump 51 for injecting the alternative fuel such as ammonia into the fossil fuel, even if there is an individual difference in the injection pump portion when the alternative fuel such as ammonia having a lower viscosity than water is injected, the same amount of the alternative fuel can be injected into the plurality of fuel injection valves 30 … ….

In the present embodiment, ammonia is exemplified as the alternative fuel, but alternative fuels having a viscosity lower than that of water, such as methanol, for example, having a viscosity of 0.62mpa·s at 20 ℃ may be used. In addition, a fluid fuel having a viscosity lower than that of water may be used instead of petroleum.

In addition, in the present embodiment, there is provided: a flow meter 113, the flow meter 113 measuring the discharge amount of the substitute fuel from each of the injection pump units 51a, 51b, 51 c; and a control unit 92 for calculating an average discharge amount of all the injection pump units 51a, 51b, 51c for injecting the substitute fuel into the fuel injection valve 30 … … provided in the same cylinder based on the discharge amount of the substitute fuel measured by the flow meter 113, and controlling the rising amount of each of the injection pump units 51a, 51b, 51c so that the discharge amount of each of the injection pump units 51a, 51b, 51c reaches the average discharge amount based on the average discharge amount.

Accordingly, the rising amounts of the injection pump units 51a, 51b, and 51c are controlled based on the average discharge amounts of all the injection pump units, and therefore, the injection pump units 51a, 51b, and 51c discharge the alternative fuel at different rising amounts.

Thus, even if the leak amounts in the injection pump portions 51a, 51b, and 51c are different, by controlling the injection pump portions 51a, 51b, and 51c to have different rising amounts, the same amount of substitute fuel can be injected from all the injection pump portions 51a, 51b, and 51c to the fuel injection valves 30 and … …, and the injection pump portions 51a, 51b, and 51c can inject the same amount of substitute fuel to the fuel injection valves 30 and … … provided in the same cylinder.

(second embodiment)

Next, a second embodiment will be described. The second embodiment will be described with reference to a longitudinal sectional view of fig. 7 showing a detailed configuration of the first injection pump section and a control flow chart of fig. 8. Since the other structures are the same as those of the first embodiment, the same reference numerals are used and description thereof will be omitted.

In the present second embodiment, the rising amount of each of the injection pump units 51a, 51b, 51c is controlled by measuring the leakage amount of the alternative fuel leaked out of each of the injection pump units 51a, 51b, 51c, instead of measuring the injection amount of the alternative fuel as in the first embodiment.

For example, in order to measure the discharge amount of the alternative fuel, it is necessary to provide the flow meter 113 in the injection pipe 52a as in the first embodiment, but if the flow meter 113 is provided in the injection pipe 52a, flow resistance is generated in the injection pipe 52a, and there is a possibility that the discharge of the alternative fuel is adversely affected. In order to avoid such a problem, in the present embodiment, the amount of leakage of the discharge amount of each of the injection pump units 51a, 51b, and 51c is indirectly grasped by measurement, and the amount of rise of each of the injection pump units 51a, 51b, and 51c is controlled.

Specifically, as shown in fig. 7, a through hole 120 is provided in the lower portion of the housing 101 of the first injection pump portion 51a, a discharge pipe 121 for guiding the alternative fuel leaked from the through hole 120 to the outside is provided, and a leakage amount gauge 122 is provided in the middle of the discharge pipe 121. The structure is as follows: the leakage amount of the alternative fuel leaked from the fuel filling chamber 104 to the hydraulic piston 102 side is measured by the leakage amount measuring device 122.

The control of the present embodiment is performed according to the control flowchart of fig. 8.

First, at S11, the control unit 92 reads various information. Mainly, various information required for controlling the engine is read from the detection unit 91.

Next, in S12, the leakage amount of each of the injection pump units 51a, 51b, and 51c is measured by the leakage amount measuring device 122.

Then, in S13, the control unit 92 subtracts the measured leakage amount from the stroke volume of each of the injection pump units 51a, 51b, and 51c, and calculates the estimated injection amount.

Then, at S14, an average estimated ejection amount is calculated from the estimated ejection amount. Specifically, the calculated average estimated ejection amount is obtained by adding all of the estimated ejection amount of the first injection pump portion 51a, the estimated ejection amount of the second injection pump portion 51b, and the estimated ejection amount of the third injection pump portion 51c, and dividing the sum by 3.

Then, in S15, the pump-up amounts of the first, second, and third injection pump units 51a, 51b, 51c are controlled so that the estimated ejection amounts of the injection pump units 51a, 51b, 51c reach the average estimated ejection amount.

Then, the process proceeds to return in preparation for the next control cycle.

By controlling as described above, the rising amounts of the injection pump units 51a, 51b, and 51c are controlled so that the discharge amounts of all the injection pump units are equal.

Accordingly, the fuel injection pump units 51a, 51b, and 51c inject the same amount of the substitute fuel and supply the same amount of the substitute fuel to the fuel injection valves 30 and … …, and thus the combustion chamber 17 … … of the same cylinder of the engine 1 is stably operated in a mixed combustion state, thereby operating the engine 1.

As described above, in the present embodiment, it includes: a leakage amount measuring device 122, the leakage amount measuring device 122 measuring the leakage amount of the substitute fuel from each of the injection pump portions 51a, 51b, 51c, the injection pump portions 51a, 51b, 51c injecting the substitute fuel into the fuel injection valve 30 … … provided in the same cylinder; and a control unit 92, wherein the control unit 92 calculates an estimated injection amount of the alternative fuel injected into the fuel injection valve 30 … … provided in the same cylinder from the estimated injection amount by subtracting the leakage amount of the alternative fuel measured by the leakage amount measuring device 122 from the stroke volume of each of the injection pump units 51a, 51b, 51c, and uses the obtained value as the estimated injection amount of each of the injection pump units 51a, 51b, 51c, and calculates an average estimated injection amount of all the injection pump units injecting the alternative fuel from the estimated injection amount, and controls the rising amount of each of the injection pump units 51a, 51b, 51c so that the injection amount of each of the injection pump units 51a, 51b, 51c reaches the average estimated injection amount.

Accordingly, the rising amounts of the injection pump units 51a, 51b, and 51c are controlled based on the average estimated injection amounts of the injection pump units 51a, 51b, and 51c, respectively, and therefore, the injection pump units 51a, 51b, and 51c inject the alternative fuel at different rising amounts, respectively. That is, it is considered that the different leak amounts of the respective injection pump portions 51a, 51b, and 51c mean different discharge amounts, and therefore, even when the flow rate of the substitute fuel actually discharged cannot be measured, the leak amounts are measured to control the rising amounts of the respective injection pump portions 51a, 51b, and 51c, and the same amount of the substitute fuel is supplied to the respective fuel injection valves.

Accordingly, even if the leak amount differs between the injection pump portions 51a, 51b, and 51c, the injection pump portions 51a, 51b, and 51c are controlled to have different rising amounts, and therefore, the same amount of substitute fuel can be supplied from all the injection pump portions 51a, 51b, and 51c to the plurality of fuel injection valves 30 … …, wherein the injection pump portions 51a, 51b, and 51c inject the substitute fuel to the fuel injection valves 30 … … provided in the same cylinder.

(third embodiment)

Next, a third embodiment will be described. The third embodiment will be described with reference to a longitudinal sectional view of fig. 9 showing a detailed configuration of the first injection pump section and a control flowchart of fig. 10. Since the other structures are the same as those of the first embodiment, the same reference numerals are used and description thereof will be omitted.

In the third embodiment, the rising rate of the hydraulic piston 102 of the first filling pump unit 51a is measured by the rising rate measuring device 130, whereby the rising amount of each of the filling pump units 51a, 51b, and 51c is controlled.

For example, in the case of measuring the discharge amount of the alternative fuel or the leakage amount of the alternative fuel, it is necessary to provide a flow meter or the like in the flow path, but if such a flow meter or the like is provided in the flow path of the alternative fuel, flow resistance occurs. In order to avoid such flow resistance, in the present embodiment, the rate of rise of the hydraulic piston 102, at which the discharge amount of the alternative fuel can be indirectly grasped, is measured to control the amount of rise of the injection pump units 51a, 51b, 51 c. The following may be used: instead of measuring the rising speed of the hydraulic piston 102, the rising speeds of the plunger 103 and the sleeve member 109 are measured.

Specifically, as shown in fig. 9, the constitution is: the rising speed measuring device 130 is provided, and the rising speed of the hydraulic piston 102 ejecting the alternative fuel is measured in the first filling pump portion 51a, wherein the rising speed measuring device 130 measures the movement of the lower side surface of the hydraulic piston 102 of the first filling pump portion 51 a.

The control of the present embodiment is performed according to the control flowchart of fig. 10.

First, in S21, the control unit 92 reads various information. Mainly, various information required for controlling the engine is read from the detection unit 91.

Next, in S22, the raising speed of the hydraulic piston 102 of each of the injection pump units 51a, 51b, and 51c is measured by the raising speed measuring device 130.

Then, in S23, the control unit 92 calculates the estimated ejection amount from the rising speed of each of the injection pump units 51a, 51b, and 51 c. For example, when the rising speed is high, it is estimated that the ejection amount is small. That is, it is considered that a large rising speed means that the hydraulic piston 102 has small resistance and does not cause a large amount of leakage, and therefore it is considered that it is reasonable to estimate that the discharge amount is small in this case.

Then, at S24, an average estimated ejection amount is calculated from the estimated ejection amount. Specifically, the calculated average estimated ejection amount is obtained by adding all of the estimated ejection amount of the first injection pump portion 51a, the estimated ejection amount of the second injection pump portion 51b, and the estimated ejection amount of the third injection pump portion 51c, and dividing the sum by 3.

Then, in S25, the pump-up amounts of the first, second, and third injection pump units 51a, 51b, 51c are controlled so that the estimated ejection amounts of the injection pump units 51a, 51b, 51c reach the average estimated ejection amount.

Then, the process proceeds to return in preparation for the next control cycle.

By performing the control as described above, in the present embodiment, the rising amounts of the respective injection pump units 51a, 51b, 51c are controlled so that the discharge amounts of all the injection pump units 51a, 51b, 51c reach the same level.

Accordingly, since the substitute fuel in approximately equal amounts is discharged from all the injection pump portions 51a, 51b, and 51c and supplied to the fuel injection valves 30 and … …, the engine 1 is operated in a stable mixed combustion state in the combustion chamber 17 … … of the same cylinder of the engine 1.

As described above, in the present embodiment, it includes: a rising speed measuring instrument 130, wherein the rising speed measuring instrument 130 measures the rising speed of each of the injection pump portions 51a, 51b, 51c for injecting the substitute fuel into the fuel injection valve 30 … … provided in the same cylinder; and a control unit 92, wherein the control unit 92 calculates estimated discharge amounts of the respective injection pump units 51a, 51b, and 51c based on the rising speed measured by the rising speed measuring device 130, calculates average estimated discharge amounts of all the injection pump units based on the estimated discharge amounts, and controls the rising amounts of the respective injection pump units 51a, 51b, and 51c so that the discharge amounts of the respective injection pump units 51a, 51b, and 51c reach the average estimated discharge amounts.

Accordingly, the rising amounts of the injection pump units 51a, 51b, and 51c are controlled based on the average estimated injection amounts, and therefore, the injection pump units 51a, 51b, and 51c inject the alternative fuel at different rising amounts. That is, it is considered that the different rising speeds of the respective injection pump portions 51a, 51b, and 51c mean different injection amounts, and therefore, even when the flow rate of the substitute fuel actually injected cannot be measured, the rising speeds are measured to control the rising amounts of the respective injection pump portions 51a, 51b, and 51c, and the same amount of the substitute fuel is supplied to the respective fuel injection valves 30 … ….

By measuring the rising speed of each of the injection pump units 51a, 51b, and 51c, the discharge amounts of each of the injection pump units 51a, 51b, and 51c are thereby indirectly estimated, and the discharge amounts of all the injection pump units 51a, 51b, and 51c for injecting the substitute fuel into the fuel injection valve 30 … … provided in the same cylinder can be kept approximately the same.

(fourth embodiment)

Next, a fourth embodiment will be described. The fourth embodiment will be described with reference to a longitudinal sectional view of fig. 11 showing a detailed configuration of the first injection pump section and a control flowchart of fig. 12. Since the other structures are the same as those of the first embodiment, the same reference numerals are used and description thereof will be omitted.

In the fourth embodiment, the plunger internal pressure measuring device 140 measures the pressure in the fuel filling chamber 104 of the first injection pump portion 51a, thereby controlling the rising amount of each of the injection pump portions 51a, 51b, and 51 c.

For example, if the rising speed of the hydraulic piston 102 is measured as in the third embodiment, the discharge amount of the alternative fuel may not be accurately estimated due to the sliding resistance of the hydraulic piston 102 or the like. In the present embodiment, the rising amount of the injection pump units 51a, 51b, and 51c is controlled by directly measuring the pressure in the fuel filling chamber 104 to estimate the discharge amount of the alternative fuel.

Specifically, as shown in fig. 11, the constitution is: a plunger internal pressure measuring device 140 is provided for measuring the pressure in the fuel filling chamber 104 of the first filling pump part 51a, and the first filling pump part 51a measures the pressure change in the fuel filling chamber 104 when the substitute fuel is discharged.

The control of the present embodiment is performed according to the control flowchart of fig. 12.

First, in S31, the control unit 92 reads various information. Mainly, various information required for controlling the engine is read from the detection unit 91.

Next, in S32, the plunger internal pressure of each of the injection pump portions 51a, 51b, and 51c, that is, the pressure in the fuel filling chamber 104 is measured by the plunger internal pressure measuring device 140.

Then, in S33, the control unit 92 calculates the estimated injection amount from the plunger internal pressures of the injection pump units 51a, 51b, and 51 c. For example, when the plunger internal pressure is low, the amount of ejection is estimated to be small. That is, since a low plunger internal pressure means that a large amount of leakage occurs, it is considered reasonable to estimate that the discharge amount is small in this case.

Then, at S34, an average estimated ejection amount is calculated from the estimated ejection amount. Specifically, the calculated average estimated ejection amount is obtained by adding all of the estimated ejection amount of the first injection pump portion 51a, the estimated ejection amount of the second injection pump portion 51b, and the estimated ejection amount of the third injection pump portion 51c, and dividing the sum by 3.

Then, in S35, the pump-up amounts of the first, second, and third injection pump units 51a, 51b, 51c are controlled so that the estimated ejection amounts of the injection pump units 51a, 51b, 51c reach the average estimated ejection amount.

Then, the process proceeds to return in preparation for the next control cycle.

As described above, in the present embodiment, it includes: a plunger internal pressure measurement device 140, wherein the plunger internal pressure measurement device 140 measures the internal pressure of the fuel filling chamber when the injection pump units 51a, 51b, 51c rise, and the injection pump units 51a, 51b, 51c inject the substitute fuel into the fuel injection valve 30 … … provided in the same cylinder; and a control unit 92, wherein the control unit 92 calculates estimated injection amounts of the injection pump units 51a, 51b, and 51c based on the internal pressure measured by the plunger internal pressure measuring device 140, calculates average estimated injection amounts of all the injection pump units 51a, 51b, and 51c for injecting the substitute fuel into the fuel injection valve 30 … … provided in the same cylinder based on the estimated injection amounts, and controls the rising amounts of the injection pump units 51a, 51b, and 51c so that the injection amounts of the injection pump units 51a, 51b, and 51c reach the average estimated injection amounts.

Accordingly, the rising amounts of the injection pump units 51a, 51b, and 51c are controlled based on the average estimated injection amounts, and therefore, the injection pump units 51a, 51b, and 51c inject the alternative fuel at different rising amounts. That is, it is considered that the difference in the internal pressure at the time of rising of each of the injection pump portions 51a, 51b, and 51c means that the discharge amount is different, and therefore, even when the flow rate of the substitute fuel to be actually discharged cannot be measured, the internal pressure at the time of rising is measured to control the rising amount of each of the injection pump portions 51a, 51b, and 51c, and thereby the same amount of the substitute fuel is supplied to each of the fuel injection valves 30 … ….

By measuring the internal pressure of the injection pump units 51a, 51b, and 51c when the injection pump units 51a, 51b, and 51c are raised, the discharge amounts of the injection pump units 51a, 51b, and 51c can be estimated indirectly, and the discharge amounts of all the injection pump units 51a, 51b, and 51c for injecting the substitute fuel into the fuel injection valve 30 … … provided in the same cylinder can be kept approximately the same.

(other embodiments)

While the embodiments have been described above, the invention of the present application is not limited to this, and the invention of the present application is also included in the technical scope of the invention of the present application as long as the injection pump units can be controlled so that the injection amount is kept equal even if the substitute fuel injected from the injection pump units is a substance having a low viscosity and causing leakage as ammonia.

The alternative fuel is not limited to ammonia, and may be any fuel as long as it is a fuel having a lower viscosity than water, such as biofuel or methanol.

Industrial applicability

In summary, the present invention relates to a fuel injection system for a marine engine or the like comprising an injection pump. In particular, the present invention is useful in a fuel injection system including an injection pump for injecting an alternative fuel such as ammonia into fossil fuel.

Claims

1. A fuel injection system for a multi-cylinder engine that mixes fossil fuel and alternative fuel in a combustion chamber, the fuel injection system comprising an injection pump that supplies alternative fuel of the fossil fuel and the alternative fuel to a fuel injection valve, the fuel injection system characterized by:

the injection pump includes a plurality of injection pump portions configured to inject the alternative fuel to each of the fuel injection valves,

the fuel injection system includes injection amount control means for controlling the injection amount of the alternative fuel in each of the injection pump units so as to be equal to the injection amount of the alternative fuel in the other injection pump units that inject the alternative fuel into the fuel injection valve provided in the same cylinder.

2. The fuel injection system of claim 1, wherein:

the injection amount control unit includes:

an ejection amount measuring unit that measures an ejection amount of the substitute fuel from each injection pump unit that injects the substitute fuel to a fuel injection valve provided in the same cylinder;

an average injection amount calculation unit that calculates an average injection amount of all injection pump units that inject the substitute fuel into the fuel injection valves provided in the same cylinder, based on the injection amount of the substitute fuel measured by the injection amount measurement unit; and

And a rise control means for controlling the rise of each injection pump unit so that the discharge amount of each injection pump unit reaches the average discharge amount, based on the average discharge amount calculated by the average discharge amount calculation means.

3. The fuel injection system of claim 1, wherein:

the injection amount control unit includes:

a leakage amount measurement unit that measures a leakage amount of the substitute fuel from each injection pump unit that injects the substitute fuel to a fuel injection valve provided in the same cylinder;

a discharge amount estimating unit that calculates a discharge amount of the alternative fuel measured by the discharge amount measuring unit subtracted from a stroke volume of each of the injection pump units, and uses the obtained value as an estimated discharge amount of each of the injection pump units;

an average estimated injection amount calculation means for calculating an average estimated injection amount of all injection pump units that inject the substitute fuel into the fuel injection valves provided in the same cylinder, based on the estimated injection amount of the substitute fuel calculated by the injection amount estimation means; and

And a rise control means for controlling the rise of each injection pump unit so that the discharge amount of each injection pump unit reaches the average estimated discharge amount, based on the average estimated discharge amount calculated by the average estimated discharge amount calculation means.

4. The fuel injection system of claim 1, wherein:

the injection amount control unit includes:

a rising speed measuring unit that measures a rising speed of each injection pump unit that injects the substitute fuel into a fuel injection valve provided in the same cylinder;

a discharge amount estimation unit that calculates an estimated discharge amount of each injection pump unit based on the rise rate measured by the rise rate measurement unit;

5. The fuel injection system of claim 1, wherein:

the injection amount control unit includes:

an internal pressure measurement unit that measures an internal pressure when each injection pump unit that injects the substitute fuel into a fuel injection valve provided in the same cylinder rises;

a discharge amount estimation unit that calculates an estimated discharge amount of each of the injection pump units based on the internal pressure measured by the internal pressure measurement unit;