JPH02153238A - Control device for duplex fuel diesel engine - Google Patents

Abstract

PURPOSE:To simplify the structure by selectively operating the main fuel supply stopping means when the engine load is less than the reference value and a pilot fuel lower limit setting means when the engine load is more than the reference value, and constraining the main fuel control rod or a pilot fuel control rod. CONSTITUTION:In a device in which a fuel injection valve 1 possible to inject the main fuel and the pilot fuel, the rotating movement of an output shaft 22 of a governor 21 in response to the total fuel requirement quantity is transmitted to a total fuel control rod 24 through the link mechanism 23. A connecting bar 28 is attached to the rod 24 with a pivot 29, and a gas fuel control rod 26 and a pilot fuel control rod 27 are respectively connected to the both ends of the connecting bar 28, and these movement quantity in the axial direction is transmitted to each control rack rods 6, 7 of a fuel injection pump 4. Each control rod 26, 27 are constrained by each air cylinder 40, 41 so as to stop the main fuel supply when the engine load is less than the reference value and set the lower limit of the pilot fuel when the engine load is more than the reference value.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a control device for a dual fuel diesel engine, and in particular uses gas fuel as the main fuel and oil fuel such as heavy oil as the fuel for the pylon 1. The present invention relates to a control device suitable for a dual fuel diesel engine.

[Conventional technology]

As a control device for such a dual fuel diesel engine, the one described in Japanese Patent Application Laid-Open No. 61-237844 is known.

What is described in the publication is that a main fuel adjustment rod and a pilot fuel adjustment rod are provided in the fuel injection amount adjustment means of the main fuel pump and the pilot fuel pump, respectively, so as to be freely movable in the axial direction via a link mechanism, and these two adjustment rods are provided. The rods are rotatably engaged at opposite ends of a connecting bar such that the intermediate position of the connecting bar is moved axially (in the axial direction of each adjustment rod) in response to the total fuel demand provided by the governor, and the load The amount of fuel injected into the engine is adjusted accordingly. The distribution ratio of the main fuel 1It and the pilot fuel amount is controlled by providing a positioner using a pneumatic cylinder on the fuel adjustment rod to adjust the axial position of each rod, and responding to commands given from the fuel mode selection lever. Accordingly, these positioners are driven via the distribution rate controller to restrain the main fuel adjustment rod or pylon 1 to the fuel adjustment rod at a predetermined position or to restrict the range thereof.

[Problem to be solved by the invention]

According to the above-mentioned conventional technology, the fuel distribution mode can be quickly changed in response to the supply conditions of two types of fuel, and stable operation can be maintained based on the fuel distribution mode. There are advantages.

However, according to the above-mentioned conventional technology, a positioner with a complicated configuration must be used for each fuel adjustment rod in order to control fuel distribution, and this positioner is large and expensive, so it is difficult to use a small positioner. Application to dual fuel diesel engines presents problems in terms of space and price.

In particular, small dual-fuel diesel engines generally burn pilot fuel exclusively during startup, shutdown, and low load ranges, and switch to main fuel (gas fuel) operation when the load reaches a predetermined level. This is an operating mode that maintains the required minimum level.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, that is, to provide a control device for fuel distribution that has a simple configuration and is suitable for small-sized dual-fuel diesel engines.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a total fuel adjustment rod whose axial position is moved in accordance with the total fuel requirement given from a governor, and a total fuel adjustment rod that is arranged approximately parallel to and axially between the total fuel adjustment rods. A main fuel adjustment rod and a pilot fuel adjustment rod are freely movable, and a predetermined intermediate portion is pivotally connected to the total fuel adjustment rod, and both ends thereof are connected to each of the main fuel and pilot fuel adjustment rods at least in turn. a linkage mechanism that transmits the axial movement of the main fuel adjustment rod and the pilot fuel adjustment rod to fuel injection amount adjustment means for the main fuel and the pilot fuel, respectively; and a command to be given. a main fuel supply stop means for restraining the position of the main fuel adjustment rod to a position corresponding to zero of the main fuel injection amount; pilot fuel lower limit setting means for restricting the amount to a lower limit amount; and when the load of the diesel engine is less than a preset reference value, a command is given to the main fuel supply stop means, and when the load of the diesel engine is equal to or higher than the reference value, the pilot fuel lower limit setting means is provided. The present invention provides a control device for a dual fuel diesel engine, comprising fuel mode switching means for giving commands to the means.

[Effect]

With this configuration, basically, the total fuel demand given by the governor is distributed to the main fuel adjustment rod and the pilot fuel adjustment rod via the connecting bar, and the main fuel pump and the pilot fuel adjustment rod are divided according to the distribution ratio. Main fuel and pilot fuel are respectively injected into the diesel engine from the pilot fuel pump. When the load is less than a preset reference value, the main fuel supply stop means operates in response to a command from the fuel mode switching means to restrict the position of the main fuel adjustment rod to a position corresponding to zero injection amount. . As a result, the engine is controlled to pilot fuel exclusive combustion mode during startup, shutdown, and low load ranges. Further, when the amount exceeds the reference value, the pilot fuel lower limit setting means operates in response to a command from the fuel mode switching means to restrict the position of the pilot fuel adjustment rod to a position corresponding to a preset lower limit amount.

In this way, the fuel modes required for small dual-fuel diesel engines can be realized. The main fuel supply stop means and the pilot fuel lower limit setting means do not need to have an automatic setting position variable function like conventional positioners, but only have the function of restraining each fuel adjustment lot at a predetermined position. From good things, simple means (
For example, it can be configured with a single cylinder air cylinder),
The device can be made small and inexpensive.

〔Example〕

Hereinafter, the present invention will be explained based on examples.

FIG. 1 shows a system configuration diagram of an embodiment of the present invention.

One or more fuel injection valves 1 that are directly controlled are provided for each cylinder of a dual fuel diesel engine. The fuel injection valve 1 includes a gas fuel injection valve that injects gaseous fuel as main fuel, and a pilot fuel injection valve that injects oil fuel as pylon I fuel. Further, the gas fuel injection valve is driven by control oil 2 and injects gas fuel supplied through a gas fuel supply line 3 into the cylinder.

The fuel injection pump 4 serving as the fuel injection amount adjusting means is configured such that an injection pump for the control oil 2 and a pilot fuel injection pump for injecting the pilot fuel 5 are integrated. Each injection pump has a mechanism in which its discharge amount is adjusted by moving a controller 6.7 back and forth in the axial direction. Each injection pump receives pilot fuel supplied from the pilot fuel supply line 8 through the control rack 6.7.
It is designed to eject only the amount according to the position.

Since the gas fuel is under high pressure, a double pipe structure is used as shown by the broken line to prevent leakage, and the inside of the double pipe is connected to the drain line 10. Further, seal oil is supplied to necessary locations via a seal oil line 11.

Next, the characteristic parts of the control device according to this embodiment will be explained. The output shaft 22 of the governor 21 is adapted to be rotated by an angle corresponding to the total amount of fuel required by the engine. This rotational movement of the output shaft 22 is caused by the link mechanism 23
This is converted into an axial linear movement of the fuel adjustment rod 24 for each vehicle. A gas fuel adjustment rod 26 as a main fuel adjustment rod and a pilot fuel adjustment rod 27 are provided parallel to and freely movable in the axial direction with the total fuel adjustment rod 24 in between. Also,
A connecting bar 28 is rotatably attached to the total fuel adjustment rod 24 via a pivot 29. Notched grooves 28a and 28b are formed at both ends of the connecting bar 28 to extend in the longitudinal direction, and these grooves 28a and 28b are connected to pins attached to the gas fuel adjustment rods 1 to 26 and the pilot fuel adjustment rod 27. 30 and 31, respectively, and are freely slidably engaged in the longitudinal direction.

The axial movement of each fuel adjustment rod 26 and 27 is transmitted to the control rack racks 6 and 7 via linkages 32 and 33, respectively. A perspective view of the link mechanism constructed in this way is shown in FIG.

One end of the main fuel adjustment rod 26 is connected to the piston of the air cylinder 4o. On the other hand, two air cylinders 41 that extend and contract in the axial direction of the pilot fuel adjustment rod 27 sandwich the locking piece 27a of the pilot fuel adjustment rod 27.
and 42 are arranged to face each other, and each piston rod is in contact with the locking piece 27a. Control air is selectively supplied to these air cylinders 4°, 41 and 42 from a solenoid valve 43. This control air supply line has quick release valves 44 and 45, respectively.
is inserted.

Also, within the movement range of the total fuel adjustment rod 24, there is a limit switch (■) that is closed by the rod.

Sl and LS2 are arranged. The LSI detection signal is input to a delay timer 46. The output signals of the delay timer 46 and the limit switch LS2 are inputted via a switch 47 to an electromagnetic relay 48 that drives the electromagnetic valve 43. In addition, the limit switch LSI is
This is to detect that PE□ has reached a preset first reference value PE□ or more. For this reason, the total fuel adjustment rod 24 is arranged to operate when the tip reaches a position corresponding to the reference value PIEt. This reference value P1. .

is determined in accordance with the minimum value of the gas fuel injection amount that is allowable from the characteristics of the gas injection valve, and is set to, for example, about 30% with respect to the full load.

On the other hand, the limit switch LS2 detects that the engine load P has reached a preset second reference value PE2 or more, and the total fuel adjustment rod 24 has reached the reference value PE2.
It is arranged to operate when a position corresponding to 2 is reached. The value of this reference value PIE2 is set to, for example, about 60% of the full load.

The operation of the embodiment configured as described above will be explained using FIG. 3 and FIG. 4.

For diesel engines, once the starting conditions such as lubricating oil supply pressure, starting air pressure, control air pressure, and control power supply are in place (
Step 101), the engine is started by an engine starter such as an air run, and the starting speed is approximately 1100 r.
p or more), a command to shift to fuel operation is issued (step 102). Based on this step 10
3, a command is issued to the governor 21 to maintain the rated rotation NER.

As a result, the governor 21 rotates the governor output shaft (governor index) 22 according to the difference between the current rotation speed and the command rotation speed, and moves the total fuel adjustment rod 24 in the fuel increasing direction (arrow 50 in the figure) via the link mechanism 23. ). As a result, the tip of the main fuel adjustment rod 24 operates the limit switch LSI, and is limited to a position corresponding to approximately 50% load by a restriction cylinder (not shown). The reason for providing such a restriction cylinder is that since the difference in rotation speed of the governor 21 is extremely large in the early stage of startup, the governor 21 outputs the maximum governor index, and accordingly fuel is injected into the engine cylinder. This is because, since the amount of air in the cylinder is not sufficient, the injected fuel cannot be completely combusted and a large amount of soot is generated, which needs to be prevented. On the other hand, the air cylinder 4o has a solenoid valve 43
It is restrained to the most expanded position by the control air supplied from the control air, that is, the position where the gas fuel injection amount corresponds to 0%. Therefore, when the total fuel adjustment rod 24 moves in the fuel increasing direction, the connecting bar 28 is rotated counterclockwise in the figure about point C.

Therefore, point B of the pilot fuel adjustment rod 27 is moved in the fuel increasing direction (in the direction of arrow 51 in the figure).

This amount of movement is transmitted to the control rack rod 7 via the link mechanism 33, and by pushing the control rack rod 7, pilot fuel is supplied to the fuel injection valve 1. Therefore, the rotation of the governor index 22 is transmitted only to the pilot fuel adjustment rod 27, thereby starting the engine in the pilot fuel exclusive combustion mode. Then, as the rotational speed NE increases, the rotation of the governor index 22 is returned, and the total fuel adjustment rod 24 is pulled back and separated from the limit switch LSI. Note that the set time 'rs of the delay timer 46 is set to be longer than the time during which the transient increase in the governor index at startup continues. In this way (after engine rotational dispersion N [ER is reached), for example, the load generator and the power transmission bus are automatically coupled in synchronization (step 104). In this way, the load is synchronously coupled in. When the engine load increases, the total fuel adjustment rod 24 moves in the increasing direction and operates the limit switch LS1 (step 105, step 1).
06). This causes the delay timer 46 to start operating.
When the set time T s (for example, about 10 seconds) expires, the solenoid valve 43 is switched via the switch 47 and the electromagnetic relay 48 . Note that the switch 47 is a manual switch for canceling automatic operation using gas fuel, and is normally turned on. In addition, if the total fuel adjustment rod 24 moves quickly and reaches the position where the limit switch LS2 is operated before the delay timer 46 expires, the limit switch L
The solenoid valve 43 is switched by the operation signal of S2 (step 108). When the electromagnetic valve 43 is switched, the restriction by the air cylinder 40 is released, so the gas fuel adjustment rod 26 becomes freely movable. On the other hand, air cylinder 4
Control air is supplied to pylons 1 and 42, and the respective cylinders expand to restrain the pilot fuel adjustment rod 27 at a preset position corresponding to the lower limit amount (for example, 5%) of the fuel injection amount from pylon 1. In this way, the mode is switched to the pilot fuel exclusive combustion mode at startup (step 109).
). That is, 5% of the total fuel requirement corresponding to the governor index is set as pilot fuel, and the remainder is distributed to the gas fuel adjustment lot 26 via a connecting bar 28 that is linked to the movement of the total fuel adjustment lot 24. As a result, the gas fuel adjustment lot moves in the fuel increasing direction (arrow 52 in the figure).
This movement is transmitted to the control rack rod 6 via the link mechanism 32. Then, an amount of control oil 2 corresponding to the insertion/extraction position of the control rack rod is supplied to the fuel injection valve 1, and a corresponding amount of gas fuel is injected into the engine cylinder, resulting in mixed combustion mode operation of gas fuel and pilot fuel. Can be switched. Note that the air cylinder 41 is for pushing back the pilot fuel to the lower limit amount when switching to the mixed combustion mode of gas fuel and pilot fuel, and the air cylinder 42 is for ensuring the lower limit amount of the pilot fuel. , the air cylinder 42 uses a piston with a larger diameter than the air cylinder 41.

Furthermore, when the load PE decreases during co-combustion mode operation and drops below the first reference value PE1 (step 111), the total fuel adjustment lot 24 turns off the limit switch LSI, so the electromagnetic relay 48 turns off, and the electromagnetic valve 43 is switched, and the mode is switched to pylon 1 - fuel exclusive combustion mode (step 112).

Note that the electromagnetic relay 48 is switched from the mixed combustion operation mode to the pylon I due to an abnormal signal from other safety devices (not shown).
- The mode is switched to fuel-only combustion mode (step 110). After switching to the pilot fuel exclusive combustion mode in step 12 in this manner, the process proceeds to step 113 where it is determined whether or not the engine should be stopped, and if the judgment is affirmative, the engine is stopped in step 114. On the other hand, step]
If the determination in step 13 is that there is no need to stop the engine, the process returns to step 105. Then, when the load increases and the limit switch LSI is operated again, the operation is shifted to the mixed combustion mode using the same procedure as described above.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to realize a small and inexpensive fuel distribution device with a simple configuration suitable for a small dual-fuel diesel engine.

[Brief explanation of the drawing]

Fig. 1 is a system configuration diagram of one embodiment of the present invention, and Fig. 2 is a system configuration diagram of an embodiment of the present invention.
A perspective view of the link mechanism of the illustrated embodiment, FIG. 3 is a flowchart 1-1 showing the operation procedure of the illustrated embodiment in FIG. 1, and FIG. 4 is a time chart 1-1 explaining the operation of the illustrated embodiment in FIG. 1. It is.

Claims (1)

[Claims] 1. A total fuel adjustment rod whose axial position is moved according to the total fuel requirement given by the governor, and a main fuel adjustment that is provided approximately parallel to the total fuel adjustment rod and freely movable in the axial direction. A connection comprising a rod and a pilot fuel adjustment rod, and a predetermined intermediate portion is pivotally connected to the total fuel adjustment rod, and both ends are engaged at least rotatably with each of the main fuel and pilot fuel adjustment rods, respectively. a link mechanism that transmits the axial movement of the main fuel adjustment rod and the pilot fuel adjustment rod to fuel injection amount adjustment means for the main fuel and the pilot fuel, respectively; Main fuel supply stop means for restraining the position corresponding to zero of the main fuel injection amount, and pilot fuel lower limit setting means for restraining the position of the pilot fuel adjustment rod to the lower limit amount of the pilot fuel injection amount set by a given command. and fuel mode switching means that gives a command to the main fuel supply stop means when the load of the diesel engine is less than a preset reference value, and gives a command to the pilot fuel lower limit setting means when the load of the diesel engine is equal to or higher than the reference value. , a control device for a dual fuel diesel engine.