A method for controlling the fuel supply of a marine mechanical pump diesel engine

Abstract

The application discloses a kind of marine mechanical pump diesel engine oil control method, belong to marine diesel engine technical field, comprising: monitoring instrument obtains the boost air pressure and speed of diesel engine, when the speed of diesel engine does not exceed idle speed, start oil limiting function;When the speed of diesel engine exceeds idle speed but does not exceed set speed, and current boost air pressure is lower than first air pressure value, start oil limiting function;Set speed is the limit speed that diesel engine does not smoke when suddenly accelerating after beat, and first air pressure value is the boost air pressure required for set speed, the method can limit oil when the speed of diesel engine does not exceed idle speed, simultaneously can also limit oil when the speed of diesel engine exceeds idle speed but does not exceed set speed, i.e. beat condition and beat sudden working condition under intake deficiency, avoid the phenomenon that the above-mentioned condition appears that supply oil quantity is greater than demand oil quantity, combustion is not sufficient and leads to smoking.

Description

Technical Field

[0001] This invention belongs to the field of marine diesel engine technology, specifically relating to a fuel limiting control method for a marine mechanical pump diesel engine. Background Technology

[0002] Marine diesel engines are the main propulsion system for ships or the power source for power stations. The manufacturing technology of marine medium- and high-speed high-power diesel engines is extremely complex, with the fuel injection system being a key component. It not only demands high performance but also ensures safety and reliability. Its function is like the "heart" of the engine, using extremely precise timing and metering control to deliver high-pressure fuel to the engine cylinders, thereby achieving a highly efficient working process.

[0003] When the fuel injection system is working, the boosted air needs to match the fuel supply to ensure complete combustion. For large-bore mechanical pump diesel engines, smoke may occur under certain operating conditions. The specific reason is insufficient air intake, where the actual fuel supply from the mechanical injection pump is greater than the required fuel, resulting in incomplete combustion and smoke.

[0004] Since incomplete combustion of fuel causes serious environmental damage and does not meet national standards for ship emissions, fuel quantity needs to be limited and combustion optimized in certain operating conditions to solve the above-mentioned smoke problem. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a fuel limiting control method for marine mechanical pump diesel engines, which achieves reasonable combustion and effectively solves the smoke problem by controlling the amount of fuel during the start-up, start-up, and sudden acceleration processes of the diesel engine.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] A method for limiting fuel consumption in a marine mechanical pump diesel engine includes: a monitor acquiring the boost air pressure and speed of the diesel engine; activating a fuel limiting function when the diesel engine speed does not exceed the idle speed; activating the fuel limiting function again when the diesel engine speed exceeds the idle speed but does not exceed a set speed, and the current boost air pressure is lower than a first pressure value; the set speed is a limiting speed at which the diesel engine will not produce smoke when it suddenly accelerates after being engaged, the engagement of the diesel engine is the process of the diesel engine connecting to the propeller from no-load, and the first pressure value is the boost air pressure required for the set speed.

[0008] Furthermore, when the diesel engine speed exceeds the set speed, the fuel limiting function is turned off.

[0009] Furthermore, when the boost air pressure of the diesel engine exceeds or equals the second air pressure value, the fuel limiting function is turned off; the second air pressure value is the boost air pressure corresponding to the load value after the diesel engine completes its sudden acceleration.

[0010] Furthermore, when the diesel engine speed exceeds the idle speed, the system continues to determine whether the fuel limiting function is turned off when the boost air pressure of the diesel engine exceeds or equals the first air pressure value, or when the current speed exceeds the set speed.

[0011] Furthermore, the diesel engine idles at 40% of its rated speed.

[0012] Furthermore, the set rotational speed is 500-600 rpm.

[0013] Furthermore, the set rotational speed is 550 rpm.

[0014] Furthermore, the first air pressure value is 4 kPa, and the second air pressure value is 6 kPa.

[0015] Furthermore, the fuel limiting function specifically involves the monitoring device sending a fuel limiting signal to the fuel limiting device, which then activates to push the throttle lever downshift to limit fuel consumption.

[0016] Furthermore, after receiving the fuel limiting signal from the monitoring instrument, the solenoid valve of the fuel limiting device opens the air line of the fuel cut-off cylinder, causing the piston of the fuel cut-off cylinder to move and transmit the motion to the throttle lever.

[0017] After adopting the above technical solution, the beneficial effects of the present invention are:

[0018] The marine mechanical pump diesel engine fuel limiting control method of the present invention includes: a monitoring instrument acquiring the boost air pressure and speed of the diesel engine; when the diesel engine speed does not exceed the idle speed, the fuel limiting function is activated; when the diesel engine speed exceeds the idle speed but does not exceed the set speed, and the current boost air pressure is lower than the first pressure value, the fuel limiting function is activated; the set speed is the limiting speed at which the diesel engine will not produce smoke when it suddenly accelerates after the engine is in sync; the engine sync is the process of the diesel engine connecting to the propeller from no load; the first pressure value is the boost air pressure required for the set speed. This method can limit fuel when the diesel engine speed does not exceed the idle speed during startup, avoiding the fuel supply exceeding the required fuel supply and incomplete combustion leading to smoke. At the same time, it can also limit fuel when the diesel engine speed exceeds the idle speed but does not exceed the set speed during startup and when there is insufficient air intake during sudden acceleration after startup, avoiding the phenomenon of the fuel supply exceeding the required fuel supply and incomplete combustion leading to smoke. Attached Figure Description

[0019] Figure 1This is a schematic diagram of the control flow of the marine mechanical pump diesel engine fuel limiting control method of the present invention;

[0020] Figure 2 This is a schematic diagram of the oil limiting device;

[0021] In the diagram, 1-control air interface, 2-air filter, 3-control air pipe, 4-solenoid valve, 5-fuel cut-off cylinder, 6-connecting rod, 7-sleeve. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the textual part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0023] In the description of this specification, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0024] In the description of this specification, unless otherwise expressly defined, the terms "setting", "installation", "connection", etc. should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in combination with the specific content of the technical solution.

[0025] like Figure 1 As shown, a fuel limiting control method for a marine mechanical pump diesel engine includes: a monitoring device acquiring the boost air pressure and speed of the diesel engine; and activating the fuel limiting function when the diesel engine speed does not exceed the idle speed N1. After the diesel engine starts, the monitoring device begins to judge according to the fuel limiting logic. Fuel limiting is performed when the diesel engine speed does not exceed the idle speed N1, i.e., when the diesel engine is in starting condition, to avoid incomplete combustion and smoke caused by slow boost air pressure response and insufficient air intake. The idle speed N1 of the marine diesel engine is 40% of the rated speed.

[0026] like Figure 1 As shown, when the diesel engine speed exceeds the idle speed N1 but does not exceed the set speed N2, and the current boost air pressure is lower than the first pressure value B1, i.e., when the diesel engine is in a synchronized operating condition or a sudden acceleration condition after synchronized operation with insufficient air intake, the fuel limiting function is activated. This prevents insufficient boost air pressure caused by the decrease in engine speed during synchronized operation, resulting in less fuel demand than required, while the actual fuel supply exceeds the demand; and prevents incomplete combustion and smoke during synchronized operation when the throttle is suddenly increased after synchronized operation due to the slow boost pressure response and insufficient air intake.

[0027] The set speed N2 is the limiting speed at which the diesel engine will not produce smoke during sudden acceleration after engagement. This set speed N2 is the speed during the incomplete acceleration process after engagement, where the engagement of the diesel engine refers to the process of connecting the diesel engine to the propeller from no-load. The set speed N2 is generally 500–600 rpm. However, since the models of various equipment on different ships are not entirely consistent, the specific set speed N2 needs to be determined through testing and calibration based on the actual parameters of the ship when performing logical judgments. In this embodiment, a set speed N2 of 550 rpm is preferred.

[0028] Wherein, the first air pressure value B1 is the boost air pressure required to set the rotation speed N2. The first air pressure value B1 is obtained through experimental calibration. In this embodiment, the preferred first air pressure value is 4 kPa.

[0029] like Figure 1 As shown, when the diesel engine speed exceeds the idle speed N1, the system continues to judge. When the boost air pressure of the diesel engine exceeds or equals the first air pressure value B1, the fuel limiting function is turned off. At this time, the boost air pressure is sufficient to meet the need for complete combustion of the fuel injected by the mechanical pump during the operating conditions, and there will be no smoke. Therefore, there is no need to continue limiting the fuel.

[0030] like Figure 1 As shown, when the diesel engine speed exceeds the idle speed N1, the system continues to judge; when the speed exceeds the set speed N2, the fuel limiting function is turned off. When the diesel engine speed exceeds the set speed N2, it means that the diesel engine has completed its synchronization, its speed has returned to the standard speed, the boost air pressure is sufficient, the fuel can burn completely, and there will be no smoke. Therefore, there is no need to continue limiting fuel.

[0031] like Figure 1 As shown, after activating the fuel limiting function, the system continues to monitor the diesel engine speed. When the engine speed exceeds the set speed N2, the fuel limiting function is deactivated. When the diesel engine suddenly accelerates after reaching its set speed, the slow boost pressure response and insufficient air intake result in an actual fuel supply exceeding the required amount, leading to incomplete combustion and smoke. Therefore, in this sudden acceleration situation, the monitor maintains the fuel limiting function until the engine speed exceeds the set speed N2. Only after the diesel engine has completed its set speed and acceleration, and its speed has returned to the standard speed and exceeded the set speed N2, is the boost air pressure sufficient for complete fuel combustion, preventing smoke. Therefore, continued fuel limiting is no longer necessary.

[0032] like Figure 1As shown, after activating the fuel limiting function, the boost air pressure of the diesel engine continues to be monitored for judgment. When the boost air pressure of the diesel engine exceeds or equals the second pressure value B2, the fuel limiting function is deactivated. The second pressure value B2 is the boost air pressure corresponding to the load value after the diesel engine completes a sudden acceleration. The second pressure value B2 is obtained through experimental calibration; in this embodiment, a preferred second pressure value is 6 kPa. During sudden acceleration after acceleration, the monitor will maintain the fuel limiting function until the boost air pressure reaches the second pressure value B2. Only after the diesel engine completes the sudden acceleration and the speed increases, does the boost air pressure increase to meet the current throttle load requirement. At this point, the boost air pressure is sufficient, the fuel can burn completely, and there will be no smoke; therefore, continued fuel limiting is not necessary.

[0033] In this application, the engine speed and boost air pressure of the diesel engine are used as judgment conditions at the same time. This allows the control logic to still be effectively executed even if the boost pressure sensor fails, by using the feedback parameters from the speed sensor.

[0034] The structure of the oil limiting device is as follows: Figure 2 As shown, the fuel limiting device includes a fuel cut-off cylinder 5, an air line, a solenoid valve 4, and a connecting rod 6. The air intake port of the fuel cut-off cylinder 5 is connected to the air line, and the solenoid valve 4 is installed on the air line to control the opening and closing of the air line. The piston of the fuel cut-off cylinder 5 is connected to the throttle lever via the connecting rod 6.

[0035] The fuel limiting function works by the monitor sending a fuel limiting signal to the fuel limiting device, which then activates, pushing the throttle lever to lower the gear and limit fuel consumption. Upon receiving the fuel limiting signal from the monitor, the solenoid valve 4 of the fuel limiting device opens the air line to the fuel cut-off cylinder 5, causing the piston in the fuel cut-off cylinder 5 to move and transmit the motion to the throttle lever.

[0036] like Figure 2 As shown, specifically, the air pipeline includes a control air interface 1 and a control air pipe 3, with a solenoid valve 4 mounted on the control air pipe 3. An air filter 2 is installed between the control air interface 1 and the control air pipe 3 to filter the air entering the air pipeline, ensuring the cleanliness of the air entering the air pipeline and preventing impurities from adhering to the solenoid valve 4 or the fuel cut-off cylinder 5, which could lead to malfunction.

[0037] like Figure 2 As shown, the connecting rod 6 is rotatably connected to the piston of the fuel cut-off cylinder 5. One end of the connecting rod 6 is a sleeve 7, which can be fitted onto the throttle lever, so that when the piston moves horizontally, it can drive the throttle lever to rotate. The sleeve 7 will not disengage from the throttle lever, so that when the fuel limiting function is activated, the throttle lever can be pushed to the low fuel position, and when the fuel limiting function is deactivated, the throttle lever can be pulled back to the position before the fuel limiting function.

[0038] When the monitoring device determines that fuel limiting logic needs to be executed based on the judgment logic, it sends a fuel limiting command to solenoid valve 4. Solenoid valve 4 opens the air vent, and control air enters the fuel cut-off cylinder 5 through control air interface 1, air filter 2, and control air pipe 3. The control air pushes the control piston inside the fuel cut-off cylinder, and finally drives the throttle lever to the low fuel level through the connecting rod 6 connected to the piston. The amount of fuel injected by the mechanical pump is reduced, limiting the amount of fuel injected and realizing the low-speed fuel limiting function.

[0039] When the monitoring device needs to disable the oil limiting function according to the judgment logic, it sends an unlimited oil command to solenoid valve 4. Solenoid valve 4 is normally closed, and the oil limiting logic is not executed.

[0040] The marine mechanical pump diesel engine fuel limiting control method of the present invention obtains the boost air pressure and speed of the diesel engine through a monitoring instrument. When the diesel engine speed does not exceed the idle speed, the fuel limiting function is activated; when the diesel engine speed exceeds the idle speed but does not exceed the set speed, and the current boost air pressure is lower than the first air pressure value, the fuel limiting function is activated. It can limit fuel when the diesel engine speed does not exceed the idle speed (starting condition), and can also limit fuel when the diesel engine speed exceeds the idle speed but does not exceed the set speed (synchronous operation condition) or when there is insufficient air intake after synchronization, thus avoiding the problem of insufficient fuel supply and smoke caused by incomplete combustion.

[0041] While specific embodiments of the present invention have been described above, those skilled in the art should understand that the described embodiments are merely some, not all, of the present invention. These are merely illustrative examples, and the scope of protection of the present invention is defined by the claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention and without any inventive effort, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for limiting fuel consumption in a marine mechanical pump diesel engine, characterized in that, include: The monitor acquires the boost air pressure and speed of the diesel engine. When the diesel engine speed does not exceed the idle speed, the fuel limiting function is activated. When the diesel engine speed exceeds the idle speed but does not exceed the set speed, and the current boost air pressure is lower than the first air pressure value, the fuel limiting function is activated; The set speed is the speed limit at which the diesel engine will not produce smoke when it suddenly accelerates after being engaged. The engagement of the diesel engine is the process of connecting the diesel engine to the propeller from no load. The first air pressure value is the boost air pressure required for the set speed.

2. The marine mechanical pump diesel engine fuel limiter control method according to claim 1, characterized by, When the speed of the diesel engine exceeds the set speed, the fuel limiting function is turned off.

3. The marine mechanical pump diesel engine fuel limiter control method according to claim 1, characterized by, When the boost air pressure of the diesel engine exceeds or equals the second air pressure value, the fuel limiting function is turned off; the second air pressure value is the boost air pressure corresponding to the load value after the diesel engine completes its sudden acceleration.

4. The marine mechanical pump diesel engine fuel limiter control method according to claim 1, characterized by, If the diesel engine speed exceeds the idle speed, the determination continues. If the boost air pressure of the diesel engine exceeds or equals the first air pressure value, or the current speed exceeds the set speed, the fuel limiting function is turned off.

5. The marine mechanical pump diesel engine fuel limiter control method according to claim 1, characterized by, The diesel engine idles at 40% of its rated speed.

6. The method for limiting fuel consumption in a marine mechanical pump diesel engine according to claim 1, characterized in that, The set speed is 500-600 rpm.

7. The marine mechanical pump diesel engine fuel limiter control method according to claim 6, characterized in that, The set speed is 550 rpm.

8. The marine mechanical pump diesel engine fuel limiter control method according to claim 3, characterized by, The first air pressure value is 4 kPa, and the second air pressure value is 6 kPa.

9. A marine mechanical pump diesel engine limited fuel control method according to any one of claims 1 to 8, characterised in that, The fuel limiting function specifically involves the monitoring device sending a fuel limiting signal to the fuel limiting device, which then activates by pushing the throttle lever to lower the gear and limit fuel consumption.

10. The marine mechanical pump diesel engine fuel limiter control method according to claim 9, characterized in that, After receiving the fuel limiting signal from the monitoring instrument, the solenoid valve of the fuel limiting device opens the air line of the fuel cut-off cylinder, causing the piston of the fuel cut-off cylinder to move and transmit the motion to the throttle lever.

Images