KR20140025478A - Fluid system and internal combustion engine - Google Patents

Abstract

The fluid system for the internal combustion engine comprises at least a first fluid circuit 1 and a second fluid circuit 2, each of the first fluid circuit 1 and the second fluid circuit 2 being part of a subsystem of the internal combustion engine. To form. The fluid system also includes a pump 3 for supplying fluid into the fluid system, and a booster device 4 having at least one intensifier 6, 7 and 8 and having at least two alternative rates of increase.

Description

FLUID SYSTEM AND INTERNAL COMBUSTION ENGINE

The present invention relates to a fluid system for an internal combustion engine according to the preamble of claim 1. The invention also relates to an internal combustion engine according to the preamble of another independent claim.

Large reciprocating engines typically have several systems that are hydraulically operated for different purposes, for example for the operation of lubrication, fuel injection and gas exchange valves. Often there are one or more pumps for each of these systems. Alternatively, a high pressure pump is used to supply hydraulic fluid at high pressure to different systems, and pressure reducing devices are used to reduce the pressure to the lower pressure level required in each system. In many applications, for example fuel injection systems in which fuel pressure is increased or injection events are controlled by separate hydraulic circuits, hydraulic pressure and flow are dependent upon operating conditions, eg the load and speed of the engine. It needs to be adjusted. The need for different pressure levels and / or flow rates leads to complex systems with multiple pumps and / or poor energy efficiency of the systems. Another disadvantage of conventional systems is that high pressure pumps with adjustable flow capacity and / or pressure are expensive.

It is an object of the present invention to provide an improved fluid system for an internal combustion engine. The fluid system includes at least a first fluid circuit and a second fluid circuit, each of the first fluid circuit and the second fluid circuit forming part of a subsystem of an internal combustion engine. Distinct features of the fluid system according to the invention are given in the characterizing part of claim 1. Another object of the present invention is to provide an improved internal combustion engine. The internal combustion engine features a fluid system according to the invention.

The fluid system according to the invention comprises an intensifier device having at least one intensifier and having at least two alternative rates of increase.

The present invention has several advantages. Since a single pump can be used to supply fluid to several fluid circuits, the total number of pumps in the engine can be reduced. Alternatively or additionally, some of the fluid circuits may have a low pressure pump instead of a high pressure pump, which helps to reduce the cost of the system. Because of the simple configuration of the intensifiers, the reliability of the system is improved. In addition, the present invention enables the adjustment of the volume flow in the second circuit by controlling the frequency of operation of the intensifiers. Pressure boosters with at least two alternative rates of increase allow the present invention to be used for fluid circuits with varying pressure requirements.

The first fluid circuit can be, for example, a gas exchange valve of the engine or a hydraulic circuit for operating the lubricating oil circuit of the engine. The second fluid circuit can be, for example, a hydraulic circuit for operating the fuel injectors of the engine or a hydraulic circuit for operating the means for pressurizing the fuel. There are different ways of implementing different rates of increase. For example, the fluid system may include two intensifiers with different rates of increase. Another option is to provide an intensifier with an intensifier having at least two increments. The pump may be a variable displacement pump that enables variable output pressures and flows. The intensifiers can be activated and stopped, for example by electrically controllable means.

According to an embodiment of the invention, each intensifier comprises a first chamber and a second chamber. The first chamber of at least one of the first chambers of the intensifiers is in fluid communication with the first fluid circuit and the second chamber of at least one of the second chambers is in fluid communication with the second fluid circuit. Each of the intensifiers further comprises a reciprocating plunger having a first pressure surface in the first chamber and a second pressure surface in the second chamber, wherein the area of the second pressure surface is smaller than the area of the first pressure surface.

According to another embodiment of the invention, the intensifiers are arranged in parallel such that the first chamber of each intensifier is in fluid communication with the first fluid circuit, and the second chamber of each intensifier is in fluid communication with the second fluid circuit. Connected. By means of two or more intensifiers connected in parallel, the second fluid circuit can be operated at a constant pressure. While one of the intensifiers pressurizes the fluid in the second fluid circuit, the other intensifiers may be reloaded. Redundancy of the intensifiers improves the reliability and safety of the system, which is particularly important for marine applications.

According to another embodiment of the invention, the system optionally comprises means for connecting the first and second intensifiers in parallel or in series. In the series connection, the first chamber of the first intensifier is in fluid communication with the first fluid circuit, the second chamber of the first intensifier is in fluid communication with the first chamber of the second intensifier, The second chamber is in fluid communication with the second fluid circuit. By this apparatus, different growth rates can be selected as needed.

1 schematically shows the main parts of a fluid system.
2 illustrates a fluid system according to an embodiment of the invention.
3 shows a fluid system according to another embodiment of the invention.
4 shows a simplified view of a piston type intensifier.

Embodiments of the present invention are now described in more detail with reference to the accompanying drawings.

In figure 1 the main part of a fluid system according to the invention is shown schematically. The fluid system includes a first fluid circuit 1 and a second fluid circuit 2. The first fluid circuit 1 and the second fluid circuit 2 are part of the subsystems of a large internal combustion engine and operate within different pressure ranges. The engine may for example be the main engine or an auxiliary engine of a ship. The first fluid circuit 1 can be, for example, a hydraulic circuit for operating a part of a lubricating oil system of the engine or gas exchange valves of the engine. The second fluid circuit 2 can be a hydraulic circuit used to operate fuel injectors of the engine or pressurize the fuel to be injected. In general, the pressure level required in the second fluid circuit 2 is higher than the pressure level required in the first fluid circuit 1. If the first fluid circuit 1 operates the gas exchange valves of the engine, the pressure of the first fluid circuit 1 may be in the range between 200 and 350 bar, for example. If the second fluid circuit 2 is used to pressurize the fuel, the pressure of the second fluid circuit 2 may be in the range between 250 and 700 bar, for example.

The fluid system includes a pump 3 for supplying pressurized fluid to the fluid system. In the embodiment of FIG. 1, the pump 3 is connected to the first fluid circuit 1 via the first fluid supply line 20 and to the second fluid circuit 2 via the second fluid supply line 21. It is used to supply fluid to the. The second fluid supply line 21 has a check valve 24 for protecting the pump 3 and the first fluid circuit 1 from the higher pressure of the second fluid circuit 2. The pump 3 is a variable displacement pump capable of supplying fluid at different pressures and flow rates. Fluid is returned from the first fluid circuit 1 to the tank 5 via the first return line 22 and from the second fluid circuit 2 to the tank 5 via the second return line 23. do.

In order to increase the pressure of the second fluid circuit 2, the fluid system is provided with a booster device 4. In order to satisfy the variable pressure requirements in the second fluid circuit 2, the booster device 4 is configured such that at least two different pressure increase rates can be selected. Different rates of increase can be achieved by different means. According to an embodiment of the invention, the booster device comprises at least two boosters. If the intensifiers have different rates of increase, the desired rate of increase can be selected by using the intensifier that best suits these operating conditions. It is also possible for different combinations of intensifiers to be used. For example, for less amplification, only one of the intensifiers is used. When greater amplification is needed, the intensifiers can be connected in series. In addition, the booster device 4 can comprise a single booster having at least two different rates of increase.

In the embodiment of FIG. 2, the first fluid circuit 1 is arranged to actuate the gas exchange valves 14 of the engine, and the second fluid circuit 2 is adapted to pressurize fuel injected into the engine. It is arranged to actuate the means 15. The booster device 4 comprises three boosters 6, 7, 8. The first intensifier 6 and the second intensifier 7 are connected in parallel. The first control valve 9 is located between the first fluid circuit 1 and the first intensifier 6, and the second control valve 10 is the first fluid circuit 1 and the second intensifier ( 7) is located between. The first control valve 9 is arranged to open and close the fluid communication between the first fluid circuit 1 and the first intensifier 6. The second control valve 10 is arranged to open and close the fluid communication between the first fluid circuit 1 and the second intensifier 7. The first intensifier 6 and the second intensifier 7 have different rates of increase. This enables different pressure amplifications depending on the required pressure level of the second fluid circuit 2. The third intensifier 8 is arranged between the first intensifier 6 and the second intensifier 7 and the second fluid circuit 2. The third control valve 11 is arranged to open and close the fluid communication between the first intensifier 6 and the second intensifier 7 and the third intensifier 8. In the embodiment of FIG. 2, the control valves 9, 10, 11 are solenoid valves. Since the control valves 9, 10, 11 can be used to prevent fluid flow from the first fluid circuit 1 to the second fluid circuit 2, the control valves are provided with pressure intensifiers 6, 7, 8. Can be used as a means for actuating and stopping.

In Fig. 4 an example of suitable intensifiers 6, 7, 8 is shown. The intensifiers 6, 7 and 8 comprise a reciprocating plunger 17 having a first pressure surface A1 and a second pressure surface A2. When the fluid is introduced into the first chamber 18 of the intensifiers 6, 7 and 8, the plunger 17 is moved. Thus, the fluid in the second chamber 19 of the intensifiers 6, 7 and 8 is pressurized. The rate of increase of the intensifiers 6, 7 and 8 depends on the ratio between the first pressure surface A1 and the second pressure surface A2.

The function of the booster device 4 is now described with reference to FIGS. 2 and 4. The drain valves 25, 26, 27 are arranged between the respective control valves 9, 10, 11 and the intensifiers 6, 7, 8. Through the drain valves 25, 26, 27, the first chamber 18 of each of the intensifiers 6, 7, 8 is fed to the tank 5 to reload the intensifiers 6, 7, 8. Is emptied. The duct connecting the second chamber 19 of each of the intensifiers 6, 7, 8 and the respective control valves 9, 10, 11 is, when the intensifiers 6, 7, 8 reloaded. A first check valve 28 is provided to allow filling of the second chamber 18 but to prevent pressurized fluid from flowing in the wrong direction. The duct through which pressurized fluid flows from each of the intensifiers 6, 7, 8 to the second fluid circuit 2 or the third intensifier 8 is passed from the second fluid circuit or the third fluid intensifier. A second check valve 29 is provided for preventing the flow from (8) to each of the intensifiers 6, 7, 8.

The fourth control valve 12 is arranged to open and close the fluid communication between the first intensifier 6 and the second intensifier 7 and the second fluid circuit 2. By the fourth control valve 12, the third intensifier 8 can be bypassed or connected in series with the intensifier of one of the first intensifier 6 and the second intensifier 7. If the third intensifier 8 is double passed, the overall rate of increase of the pressure intensifier 4 is equal to the rate of pressure increase of the pressure intensifiers 6, 7 used in the first pressure increase stage. If the third intensifier 8 is connected in series with the first intensifier 6 or the second intensifier 7, the overall rate of increase is the product of the rates of increase in the first and second stages. Thus, using the booster device according to the embodiment of FIG. 2, four different rates of increase are achieved. All control valves 9, 10, 11, 12 and drain valves 25, 26, 27 can be electrically controlled.

In the embodiment of FIG. 3, the booster device 4 includes a first booster 6 and a second booster 7. The first intensifier 6 and the second intensifier 7 may optionally be connected in parallel or in series. The function of this embodiment is described with reference to FIGS. 3 and 4. The first control valve 9 and the second control valve 10 select one of the first intensifier 6 and the second intensifier 7 for increasing the pressure of the second fluid circuit 2. To be used. When the first control valve 9 is open and the second control valve 10 is closed, the first intensifier 6 is used. The third control valve 11 and the fourth control valve 12 are used to control whether the first intensifier 6 will be used alone or in combination with the second intensifier 7. The control valves 9, 10, 11, 12 are thus optionally operated as a means for connecting the intensifiers 6, 7, 8 in parallel or in series. If the third control valve 11 is closed and the fourth control valve 12 is open, the first intensifier and the second intensifier 7 are connected in series. The fluid from the second chamber 19 of the first intensifier 6 flows into the first chamber 18 of the second intensifier 7. The overall rate of increase of the booster 4 is thus the product of the rate of increase of the first intensifier 6 and the rate of increase of the second intensifier 7. If the increase rate of the first intensifier 6 and the increase rate of the second intensifier 7 are different, three different increase rates can be achieved with the booster device 4. In addition, in this embodiment, the first intensifier 6 and the second intensifier 7 have drain valves that enable reloading of the first intensifier 6 and the second intensifier 7. 25, 26 and check valves 28, 29 for guiding the pressurized fluid in the correct direction. In addition, the booster device 4 may comprise more than two augmentation steps. For example, three intensifiers may optionally be arranged such that the three intensifiers can be connected in parallel, all three intensifiers in series, or any combination of two of the three intensifiers can be connected in series. Can be.

It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, but may be modified within the scope of the appended claims. For example, a fluid system can have more than two fluid circuits. The additional fluid circuits may have the same or different pressure levels as the first fluid circuit and the second fluid circuit.

Claims (11)

A fluid system for an internal combustion engine,
At least a first fluid circuit 1 and a second fluid circuit 2, each forming part of a subsystem of the internal combustion engine,
Further, further comprising a pump 3 for supplying fluid into the fluid system, and a booster device 4 having at least two pressure intensifiers 6, 7 and 8 and having at least two alternative rates of increase, In the fluid system for the internal combustion engine,
The booster device comprises at least a first intensifier 6 and a second intensifier 7,
Each of the first intensifier 6 and the second intensifier 7 includes a first chamber 18 and a second chamber 19,
A first chamber of at least one of the first chambers 18 is in fluid communication with the first fluid circuit 1, and a second chamber of at least one of the second chambers 19 is the second fluid. In fluid communication with the circuit 2,
Each of the first intensifier 6 and the second intensifier 7 has a first pressure surface A1 in the first chamber 18 and a second pressure surface A2 in the second chamber 19. Further comprising a reciprocating plunger 17 having:
A fluid system for an internal combustion engine, characterized in that the area of the second pressure surface (A2) is smaller than the area of the first pressure surface (A1). The method of claim 1,
The fluid system for an internal combustion engine, characterized in that the first fluid circuit (1) is a hydraulic circuit for operating the gas exchange valve (14) of the internal combustion engine. The method of claim 1,
The fluid system for an internal combustion engine, characterized in that the first fluid circuit (1) is a lubricating oil circuit of the internal combustion engine. 4. The method according to any one of claims 1 to 3,
The second fluid circuit (2) is a hydraulic circuit for operating fuel injectors (15) of the internal combustion engine. 4. The method according to any one of claims 1 to 3,
The fluid system for an internal combustion engine, characterized in that the second fluid circuit (2) is a hydraulic circuit for operating means (16) for pressurizing fuel. 6. The method according to any one of claims 1 to 5,
The intensifiers (6, 7, 8) are characterized in that they have different rates of increase. 7. The method according to any one of claims 1 to 6,
The intensifiers 6, 7 and 8 have a first chamber 18 of each of the intensifiers 6, 7 and 8 in fluid communication with the first fluid circuit 1, and the intensifier 6, 7, 8. 7, 8) Fluid system for an internal combustion engine, characterized in that each second chamber (19) is connected in parallel in fluid communication with said second fluid circuit (2). 7. The method according to any one of claims 1 to 6,
The fluid system has a first chamber 18 of the first intensifier 6 in fluid communication with the first fluid circuit 1, and a second chamber 19 of the first intensifier 6 In fluid communication with the first chamber 18 of the second intensifier 7,
And the first intensifier 6 and the second intensifier 7 in series or in parallel such that the second chamber 19 of the second intensifier 7 is in fluid communication with the second fluid circuit 2. Fluid means for an internal combustion engine, characterized in that it comprises means (9, 10, 11, 12) for selectively connecting. The method according to any one of claims 1 to 8,
The fluid system, characterized in that it comprises electrically controllable means (9, 10, 11) for actuating and stopping the intensifiers (6, 7, 8). 10. The method according to any one of claims 1 to 9,
A fluid system for an internal combustion engine, characterized in that each of the intensifiers (6, 7, 8) has at least two different rates of increase. As an internal combustion engine,
An internal combustion engine, characterized in that the fluid system according to any one of the preceding claims.

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