JPH0639916B2 - Control unit for dual fuel diesel engine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for a dual-fuel diesel engine that uses gas and oil as fuel, and particularly when supply conditions such as the supply capacity of each fuel change. Regarding suitable ones.

[Prior Art] Conventionally, generally speaking of diesel engines, A heavy oil, B
Liquid fuels such as heavy oil, heavy oil C, crude oil or by-product oil generated in the gas production process (hereinafter collectively referred to as fuel oil or oil) are often used, but LNG (natural gas), methane gas, hydrogen A gas diesel engine using a combustible gas such as gas, by-product gas or a mixed gas thereof is also known. In order to reliably and stably ignite a gas fuel having a high ignition temperature, a gas diesel engine usually injects a small amount of oil fuel as pilot fuel. Either one was used as the main fuel.

[Problems to be Solved by the Invention] However, recently, from the viewpoint of energy diversification or effective use, there is a demand for realization of a dual-fuel diesel engine that can use two types of fuels, gas and oil. Has become.

In such a dual-fuel diesel engine, when the gas and oil fuel supplies are stable,
Determine one distribution mode according to the amount of fuel supply,
If the operation control in the constant mode based on this is performed, the operation and control are also simple, and there is no particular problem.

However, when the fuel supply amount fluctuates, there is a problem that the fuel distribution pattern must often be changed according to the fluctuation. Such factors of fluctuations in the supply amount are due to, for example, fuel procurement and operation plans affected by social or economic conditions, and the fluctuation cycle is also short-term, long-term, seasonal, atmospheric temperature conditions or sunshine. There are various conditions. Especially when using by-product gas or surplus gas from the viewpoint of effective energy use,
There is a problem that the supply capacity greatly changes according to the change in the state of the gas generation source.

In order to maintain stable operation using two types of fuel with varying supply conditions, the amount of gas used is kept constant according to the supply conditions, and the amount of oil is changed according to changes in the load. It is conceivable to variably adjust. However, in this case, when the load is reduced and the amount of oil becomes close to zero, ignition becomes unstable as described above, and stable operation cannot be maintained.

Therefore, the present invention provides a control device for a dual fuel diesel engine capable of maintaining stable operation by preventing ignition instability at light load when gas is quantitatively adjusted and oil is variably adjusted according to load. The purpose is to provide.

[Means for solving problems]

The present invention, in order to achieve the above object, based on a gas quantitative mode in which the gas injection amount is fixed and the oil injection amount is variably adjusted according to the load, the total fuel demand given is set to the gas injection amount and the oil injection amount. It is characterized in that it has a fuel distribution means for distributing and distributing to the oil exclusive combustion mode when the oil injection amount becomes equal to or smaller than a predetermined value as a result of the distribution.

[Action]

With this configuration, in the gas fixed amount mode in which the gas is used, the oil injection amount of a predetermined amount or more necessary for ignition is secured, and when the oil injection amount becomes the predetermined amount or less, the use of the gas is stopped. As a result, the oil-only combustion mode is changed to stable oil operation over the entire load range.

〔Example〕

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

FIG. 1 shows a configuration diagram of a first embodiment in which the present invention is realized by using a mechanical link mechanism.

As shown in FIG. 1, this embodiment is applied to a diesel engine configured to inject fuel gas and fuel oil into a combustion chamber 3 from a fuel injection valve 2 that is inserted and attached to the top of a cylinder 1. is there. As shown in the sectional view of FIG. 2, the fuel injection valve 2 is of a double type in which a self-valve type gas injection valve and an oil injection valve are integrally formed.

In FIG. 2, the fuel oil is the fuel oil supply port 20.
1, the oil flows through the oil passage 203 formed in the axial center of the fuel oil needle 202, and is guided to the oil chamber 205 formed in the outer peripheral portion of the valve body 204 at the tip. Disc 204
Is integrated with the fuel oil needle 202 and is pressed against the valve seat portion 207 by the coil spring 206. When the pressure of the fuel oil supplied into the oil chamber 205 reaches or exceeds a predetermined value, the valve element 204 is passed through the needle 202.
Overcomes the coil spring 206 and is pushed up,
The fuel oil is ejected into the combustion chamber 3 from a fuel oil injection port 209 formed in the atomizer 208.

On the other hand, the fuel gas is introduced from the fuel gas supply port 210 and is guided to a gas passage 213 formed by the outer peripheral surface of the cylindrical fuel gas needles 211a and 211b and the outer cylinder 212. The needles 211a and 211b are slidably fitted on the outside of the valve body 214, and
The lower end of 11a is pressed against the valve seat portion 216 by the coil spring 215. The control oil for driving the gas injection valve is introduced from the control oil supply port 217 and guided to the control oil oil chamber 218 formed by the valve body 214 and the needle 211b. The needle 211b is connected to the control oil chamber 21.
When the pressure of the control oil supplied to 8 reaches or exceeds a predetermined value, the coil spring 215 is overcome and pushed up. At the same time, the needle 211a is pushed up by the pressure of the fuel gas, and the fuel gas in the gas passage 213 is injected into the combustion chamber 3 from the fuel gas injection port 228 formed in the atomizer 208. Further, the sliding surfaces of the needles 211a and 211b and the valve body 214 are kept airtight by the seal oil flowing from the seal oil supply port 229.

In the fuel injection valve 2 formed in this way, the fuel oil pressure is increased by the fuel injection pump 4 as the fuel oil injection amount control means, and the pressure is increased by the control oil injection pump 5 as the fuel gas injection amount control means. Control oil is supplied. These injection pumps 4 and 5 may be of a double type as shown in FIG. 3, for example. In the figure, the pump body 401 of the injection pump 4 has a well-known structure, and the plunger 402 has its rotational angle position adjusted by moving the control rack rod 6 in and out to control the fuel oil injection amount. ing. The same applies to the injection pump 5. Pump drive unit 40 for driving the plunger 402
3 is shared, and the plunger drive member 404
Is reciprocated up and down by a cam rotated in relation to a crankshaft (not shown) via a roller 405. Therefore, the injection pump 4,
From the discharge ports 406 and 407 of No. 5, the fuel oil and the control oil of the amounts corresponding to the positions of the control rack rods 6 and 7 are compressed to predetermined pressures, respectively, and are determined corresponding to the piston position of the diesel engine. The fuel is discharged to the fuel injection valve 2 at the injection timing.

It should be noted that the fuel injection valve 2 is not limited to the one having the above-described configuration, and a gas injection valve and an oil injection valve may be provided independently of each other, and the fuel oil or fuel gas injection amount control means includes an injection pump 4, Even if it is 5, the injection timing and the injection amount may be controlled according to the configuration of the gas injection valve or the oil injection valve.

Next, the configuration of the control device body according to the characteristic part of the present invention will be described in detail.

In the control device of the present embodiment, in order to cope with the fluctuation of the fuel supply condition, the fuel distribution mode of the fuel oil and the fuel gas is set to three basic modes as shown in Table 1, that is, the oil exclusive combustion mode I and the gas quantitative amount. It is divided into mode II and oil quantitative mode III. The oil-exclusive combustion mode I is a mode in which only fuel oil is used for operation, and is adapted to the case where fuel gas cannot be obtained or when starting up, for example.

In the gas quantitative mode II, the gas injection amount Q _G is set to a constant amount α _G ,
Oil injection depending on rotation speed or load This is an operation mode in which the amount Q ₀ is variably controlled, and is adapted to a case where the fuel gas supply amount is controlled and sufficient fuel oil is obtained, for example. Oil determination mode III
Is the case opposite to gas metering mode II, and the oil injection amount
This is an operation mode in which Q ₀ is a fixed amount α ₀ and the gas injection amount Q _G is variably controlled. In addition, since the gas exclusive combustion mode requires a certain amount of fuel oil (pilot fuel) for ignition as described above, it is substantially one mode of the oil quantitative mode III.

Here, returning to FIG. 1, the configuration of the present embodiment will be described together with the basic operation. The target rotation speed No is input from the speed controller 102 to the governor 101 as the speed control means, and the detected rotation speed N is output via the output shaft 103 of the rotation speed detector engaged with the crankshaft of the diesel engine. It has been entered. The governor 101 controls the rotation angle position of the governor output shaft 104 to increase or decrease according to the deviation ΔN between the detected rotation speed N and the target rotation speed No that fluctuates due to load fluctuations, etc., and when the deviation ΔN is zero, It is designed to hold the angular position. Also, governor output shaft 1
Reference numeral 04 is set so that the direction of rotation indicated by the arrow in the drawing is the fuel increasing direction. Therefore, the angular position of the governor output shaft 104 corresponds to the total fuel demand amount Q, and the fuel adjustment shaft 108 via the arm 105, the spring rod 106 and the arm 107.
The rotation angle of is controlled. Further, the rotation angle position of the fuel adjustment shaft 108 can be adjusted also by a manual operation handle 100.

The fuel adjustment shaft 108 is engaged with a fulcrum 120a rotatably provided at the center of the balance rod 120 via a stop mechanism 109, and the fulcrum 120a is shown by an arrow 118 in the figure according to the rotation of the fuel adjustment shaft 108. The displacement is controlled in the direction, that is, in the horizontal direction orthogonal to the axis of the balance rod 120.

As shown in FIG. 4, the slip mechanism 109 is fixed to an arm 110 fixed to an end of a fuel adjusting shaft 178 and a shaft 112 rotatably provided coaxially with the fuel adjusting shaft 108. Arm 113 and this arm 113
Guide plate 111 attached to the tip of arm 110, and spring receiver 1 fixed to arm 113 by being inserted into a through hole formed in the tip of guide plate 111.
14 and a spring 115 that presses the arm 113 against the guide plate 111 via the spring receiver 114. Further, the arm 113 includes the arm 113 and the guide plate 1.
A slip detector 11 to which a limit switch or the like is applied in order to detect that the distance from 11 is more than a predetermined dimension.
6 is provided. Therefore, when the fuel adjusting shaft 108 is rotated in the fuel increasing direction indicated by the arrow 117, the guide plate 1
The arm 113 is rotated in the same direction by 11, and the fulcrum 120a is displaced leftward in the drawing. On the contrary, when the fuel adjusting shaft 108 is rotated in the fuel reducing direction, the arm 113 is reversely rotated in accordance with the movement of the guide plate 111, and the fulcrum 120a.
Is displaced to the right in the figure. If the movement of the balance rod 120 is restrained for some reason during this fuel reduction operation, the lever 113 cannot follow the movement of the guide plate 111, and the guide plate 111 compresses the spring 115 and separates from the lever 113, and The related operation of the adjusting shaft 108 and the balance rod 120 will slip. In such a state, the fuel of the total fuel requirement amount Q or more remains supplied to the diesel engine, which causes an abnormality such as overspeed. Therefore, the above slip is detected by the slip detector 116, and based on this detection signal, the control is switched to the control capable of maintaining stable operation as described later.

Now, the fuel distribution means is a balance rod 120, and joint joints 121 and 121 are provided at both ends of the balance rod 120, respectively.
It is formed by including an oil amount adjusting rod 123, a gas amount adjusting rod 124, and positioners 125 and 126 which are connected via 122. Those rods 123 and 124
Are provided parallel to each other and freely slidable in the longitudinal axis direction.
It is connected to 7,128 via a pin. The position of the rods 123, 124 in the axial direction is determined by the positioner 1
By means of 25 and 126, it is possible to constrain the position to a value corresponding to α ₀ or α _G , such as quantitative setting, or to make it freely slidable. Therefore, the displacement amount applied to the fulcrum 120a is distributed to the axial displacement amount of the rod 123 or 124 in accordance with the constraint condition of the rod 123 or 124, and the distribution control of the fuel amount is performed as described later. It has become.

On the other hand, the other ends of these rods 123 and 124 are connected to spring rods 129 and 130, levers 131 and 132 that are rotatably supported, and fuel oil amount adjusting shaft 135 via levers 133 and 134, respectively. It is connected to the fuel gas amount adjusting shaft 136, and further these adjusting shafts 1
It is connected to the control rack rod 6 of the fuel injection pump 4 and the control rack rod 7 of the control oil injection pump 5 via arms 137 and 138 fixed to 35 and 136. Therefore, the control rack rods 6 and 7 are controlled to move in and out in proportion to the axial displacement of the rods 123 and 124. By this, the fuel oil injection pump 4 to the oil amount adjusting rod 1
A quantity of fuel oil corresponding to the axial position of 23 is supplied to the fuel injection valve 2 from the control oil injection pump 5, and a quantity of control oil corresponding to the axial position of the gas amount adjusting rod 124 is supplied to the fuel injection valve 2. From 2, the amount of fuel oil and fuel gas corresponding to the axial position of the rods 123 and 124 is injected into the combustion chamber 3.

The fixed quantity setting means is formed by including a fixed quantity setter 151 for setting a fixed quantity set value α ₀ or α _G of combustion oil or fuel gas, and an operation dial 152 thereof.

The fixed quantity setting device 151 is a variable pressure adjusting valve, and by moving the pressure adjusting body in and out by a cam that is interlocked with the dial 152, a secondary pressure of 0 to 100% (against the primary order) is set according to the fixed value of the dial. The pressure can be set continuously within the range. This quantitative setting device 151
The air of the pressure set by the
The pilot pressure of 6 is supplied to the pilot cylinder.

The positioners 125 and 126 are composed of a pilot cylinder 501 and a main cylinder 502, as shown in FIG.
In the cylinder chamber 503 of the pilot cylinder 501, the parapilot pressure is applied to the cylinder chamber 50 of the main cylinder 502.
The working air pressure is supplied to the valve 4 through the valve portion 505. The valve push rod 506 is the pilot piston 50.
When 7 is moved to the right in the figure by an amount corresponding to the pilot pressure, the valve portion 505 is opened and the working air pressure is changed to the cylinder chamber 5
04, the main piston 508 is pushed out. Then, when the valve body 509 is pushed out until it is separated from the tip end of the valve push rod 506, the working air in the cylinder chamber 504 is discharged.
The main piston 508 is pushed out by the moving amount of the pilot piston 507 via the passage 510 formed in the axial center portion of 06, and is discharged to the exhaust port 511. Then, the fuel distribution rods 123,
Numeral 124 is adapted to be held by being displaced leftward in FIG. 1 by the quantitative values α ₀ and α _G set by the quantitative setting device 151. When the pilot pressure is zero,
That is, each quantitative set value becomes 0% (α ₀ or α _G = 0%) at the position where the main piston 508 is most retracted, and when the pilot pressure is 100%, each quantitative set value becomes 100%. % (Α ₀ or α _G = 100%).

The mode setting means is operated in accordance with a mode setting device 150 for setting the fuel distribution modes I, II, and III, and a mode command output from the mode setting device 150, and operating air pressure applied to the positioner 125 or 126 or Switching valves 153, 15 for switching control of pilot pressure, etc.
4,155,156,157,158,159,160
And a shuttle valve 161.

The mode setter 150 is of a changeover switch type, and by rotating the lever to a position corresponding to each mode I, II, and III, the oil-exclusive mode I and the gas quantitative mode I are set.
I and oil quantitative mode III can be set alternatively. Further, the mode setting device 150 can be automatically switched to the oil exclusive combustion mode I by the switching drive device 170. Then, a slip detection signal from the slip detector 116 and an emergency stop command are input to the switch driver 170 via the delay timer 171 and the changeover switch 172. When these signals or commands are input, the mode is changed. The setting device 150 is switched to the oil-only firing mode I. It should be noted that the delay timer 171 is inputted with the mode commands for the gas quantitative mode II and the oil quantitative mode III, and the modes from the oil-exclusive mode I to those modes II and III.
The output of the slip detection signal is delayed for a certain period of time when switched to. As a result, unstable control operation during switching transition is prevented.

Further, when the gas quantitative mode II or the oil quantitative mode III is selected, the switching valves 153 and 154 are switched via the pressure detectors 162 and 163 by the mode commands, and at the same time, in the case of the gas quantitative mode II, The switching valves 155, 157 and 166 are designed to be switched. The pressure detectors 162 and 163 each have a fuel gas pressure of a predetermined pressure (eg, 250 kg / cm ² g) or more, and a seal oil pressure of a predetermined pressure (eg, 280 kg).
/ Cm ² g) or more. That is, the fuel gas pressure is sufficiently high, and the fuel injection valve 2
Of the operating conditions of Modes II and III using fuel gas is that the seal oil pressure required for normal operation of
It is one of them.

In addition, the mode commands of modes II and III are input to the startup control device 165 as operation commands for the fuel gas compressor and the seal oil pump. When the operation command is input, the startup control device 165 first seals. The oil pump is started, and the fuel gas compressor is started when the seal oil pressure reaches the predetermined pressure. In addition,
If the seal oil is not required due to the structure of the gas injection valve, the automatic operation control for the seal oil pump is not necessary. Conversely, even if the mode other than the fuel gas mode is used, the gas injection valve that requires the seal oil is not required. In this case, the seal oil pump is started automatically or manually when the engine is started.

By the way, in the modes using the fuel gas, that is, the gas quantitative mode II and the oil quantitative mode III, it is necessary to inject the minimum required oil amount lower limit value β as pilot fuel in order to secure ignition stability. This amount β
Varies depending on the diesel engine, but is set to about 5%, for example. In this embodiment, the fuel oil injection amount Q ₀
In order to make β greater than or equal to β, a locking rod 139 is attached to the oil amount adjusting rod 123, and the movement of this locking rod 139 is restricted by the cylinder stopper 140 in only one direction.
The oil amount adjusting rod 123 is prevented from being displaced to a position less than β. The cylinder stopper 140 is supplied with working air pressure via the switching valves 166 and 167, and the position where the cylinder piston is pushed out most is adjusted to the oil amount lower limit value β%.

Further, in the oil fixed amount mode III, that is, in the mode in which the gas injection amount is variably controlled according to the load or the rotation speed, the maximum value and the minimum value of the fuel gas usage amount may be controlled. An example of limiting the maximum value is the case where surplus gas such as LNG gas that spontaneously evaporates from the LNG tank of an LNG tanker as fuel gas, or by-product gas generated from another device is effectively used. In such a case, since the maximum value has an element that varies depending on various conditions, the maximum value must be variably set. On the other hand, the minimum value is limited mainly due to the structure and operating characteristics of the gas injection valve, and is determined according to the lower limit of the lower limit of the gas injection amount that can control the injection amount with high accuracy. Therefore, in the embodiment shown in FIG. 1, the upper limit of the gas injection amount Q _G is set in correspondence with these matters.
A gas amount upper limit setter 141 for setting H _G and a gas amount lower limit setter 142 for setting a lower limit L _G are provided.

The gas amount upper limit setting unit 141 has a pulse motor 143 driven according to a gas amount upper limit value H _G input from a setting unit (not shown), and a stopper 144 whose position is controlled by the pulse motor 143. Is formed. Then, the stopper 144 is installed at a position opposed to the locking rod 145 attached to the gas amount adjusting rod 124, and the locking rod 145 abuts the stopper 144, whereby the movement of the gas amount adjusting rod 124 is It regulates more than H _G. In addition, the gas amount upper limit setter 14
1 is provided with a gas amount upper limit detector 146 formed by applying a limit switch or the like in order to detect that the locking rod 145 is in contact with the stopper 144, and the operation (ON) of this detector 146. Switching valve 159, 160 depending on signal
Is switched to make the positioner 125, which holds the fuel oil at the fixed set value α ₀ , in a free state.
That is, the injection amount Q ₀ of the fuel oil can be variably controlled according to the increase in the total fuel demand amount Q, and the upper limit value H _{G is} substantially set.
Is changed to the gas quantitative mode II in which is the quantitative set value α _G. When the fuel demand Q decreases and the gas upper limit detector 146 is turned off, the oil fixed amount mode is set again.
It is supposed to be returned to III.

A cylinder stopper is applied to the gas amount lower limit setting unit 142, and a locking rod 147 is attached to the gas amount adjusting rod 124 so as to be able to contact the tip of the piston of this cylinder.
The position where the piston is pushed out by the working air pressure supplied via the switching valves 155 and 156 is set to the lower limit value L _G , and thereby the movement of the gas amount adjusting rod 124 is restricted to the lower limit value L _G or more. It is like this.

The emergency stop command is issued to stop the diesel engine when an abnormality (overspeed, exhaust temperature or exhaust pressure abnormal increase, fuel gas supply system abnormality, etc.) occurs in the diesel engine or related devices. When this command is input, the switching valves 173 and 174 are switched, and the working air pressure is supplied to the cylinders 175 and 176. As a result, the control rack rods 6, 7 are pulled out to the zero position via the fuel oil amount adjusting shaft 135 and the fuel gas amount adjusting shaft 136, and the injection amounts of fuel oil and fuel gas are set to zero, so that the diesel engine is stopped. It has become. At the same time, the changeover switch 172,
The switching driver 170 is operated via the delay timer 171 to switch the mode setter 150 to the oil exclusive mode I position and switch the switching valve 167 to return the cylinder stopper 140 to the zero position.

Regarding the operation of the first embodiment having the above-mentioned configuration, especially mode setting means, quantitative setting means, fuel injection amount determining means,
The related operation of the fuel distribution means and the fuel injection control means will be described.

First, the fuel distribution mode is selected and determined based on the fuel supply condition and the like, and the mode setting device 150 is operated to operate the oil exclusive mode I, the gas quantitative mode II or the oil quantitative mode III.
However, even in the present embodiment, as in the case of starting a general large diesel engine, when starting, for example, by sending compressed air into the cylinder,
After the rotation is increased to some extent, fuel oil is injected to perform a warm operation, and then the automatic operation is shifted to a steady state. Therefore, at the time of start-up (or when the fuel gas cannot be used), the oil exclusive combustion mode I is selected.

When the oil exclusive combustion mode I is switched to, the switching valves 155, 1 are operated by operating air pressure supplied via the switching valve 153.
57 is switched, and as shown in FIG. 6 (A), the positioner 125 is brought into a free state and the positioner 126 is restrained at the zero position. As a result, the gas amount adjusting rod 124
Is constrained to the Q _G = 0 position, the fuel adjustment shaft 108 is rotated according to the total fuel demand Q output from the governor 101, and the fulcrum 120 is passed through the slip mechanism 109.
When “a” is displaced, the balance rod 120 moves to the joint joint 1.
It will be tilted with 22 as a fulcrum. Therefore,
The movement of the oil amount adjusting rod 123 becomes proportional to the movement of the governor 101, and the fuel oil injection amount Q ₀ discharged from the fuel oil injection pump 4 is controlled in accordance with the total fuel demand amount Q. Next, after setting the fixed set value α _G of the fuel gas in the fixed quantity setter 151 and then switching to the gas fixed quantity mode II, an automatic operation command for the gas compressor and the seal oil pump is issued to the start control device 165. At the same time, the switching valves 156 and 158 are switched. As a result,
As shown in (B), the positioner 125 is in a free state, but the movement of the oil amount adjusting rod 123 is restricted by the cylinder stopper 140 with the β% position as the lower limit.

Then, the fuel gas pressure and the seal oil pressure become sufficiently high, and those pressure detectors 163, 164 operate (ON).
Then, the changeover valves 153, 154 are changed over, whereby the changeover valves 155, 157 are changed over to the state shown in FIG. Set value α
_The gas amount adjusting rod 124 is displaced and restrained at a position corresponding to _G. Therefore, the oil amount adjusting rod 123 and the gas amount adjusting rod 124 are, as shown in FIG. 6 (B),
The balance rod 120 is moved to the reference position (b) from the zero position (a), and the oil injection Q ₀ is abnormally controlled by β% and the gas injection amount Q _G α _G is controlled. When the gas quantitative mode II is switched to, the total fuel demand Q given from the governor 101 is normally Q ≧ (α _G + β), so that the balance rod 120 moves to Q with the joint joint 122 as a fulcrum. Is tilted accordingly. Therefore, the axial position of the oil amount adjusting rod 123 is proportionally controlled to (Q−α _G ), and as a result, as shown in FIG. 7 (A), the control oil injection pump 5 supplies the gas injection amount α _G. The control oil of the amount corresponding to is discharged to the fuel injection valve 2, and the fuel gas of α _G is injected into the combustion chamber 3,
Fuel oil of (Q-α _G ) is injected from the fuel oil injection pump 4 into the combustion chamber 3 via the fuel injection valve 2. In addition,
When Q <(α _G + β), the slip mechanism 109 operates and the mode is switched to the oil exclusive-use mode I as described above.

Next, the quantitative setter 151 sets the quantitative set value α of the fuel oil.
_{If 0} (however, α ₀ ≧ β) is set and then the mode is switched to the oil fixed amount mode III, the operation commands of the gas compressor and the seal oil pump are output to the start control device 165, and at the same time, the switching valves 156 and 158 are turned on. The state is switched to the one shown.
As a result, as shown in FIG. 6 (C), the positioner 1
26 is freed. At this time, the gas amount lower limit setting device
When the lower limit L _G of the gas injection amount Q _G is set by the 142, the movement of the gas quantity adjustment rod 124, Fig. 6
(C), the is regulated as a lower limit position corresponding to L _G.

Then, when the pressure detectors 163 and 164 are operated as in the gas metering mode II, the switching valves 153 and 154 are switched, the switching valves 156 and 158 are switched to the state shown in FIG. 1, and the positioner 125 is The oil amount adjusting rod 123 is displaced and restrained at a position corresponding to the pilot pressure set by the fixed quantity setting device 151, that is, a position corresponding to the fixed quantity set value α ₀ . Therefore, the oil amount adjusting rod 123 and the gas amount adjusting rod 124 are set to the position of the balance rod 120 as shown in FIG.
Is displaced from the reference position (C). Normally, when the oil quantity mode III is switched to, the total fuel demand Q given from the governor 101 is Q ≧ α ₀ , so the balance rod 120 is tilted according to Q with the joint joint 121 as a fulcrum. It Therefore, the axial position of the gas amount adjusting rod 124 is controlled in proportion to (Q-α ₀ ). When Q <α ₀ , the slip mechanism 109 operates and the mode is switched to the oil exclusive-use mode I as described above.

Also, if the upper limit value H _G of the gas injection amount Q _G is set by the gas quantity upper limit setting unit _{141, Q G = (Q-} α 0) the total fuel demand Q is increased and reaches the ≧ H _G , The gas amount upper limit detector 146 is operated to make the positioner 125 in a free state, and in the range of Q _G ≧ H _G , it is switched to the gas quantitative mode II in which α _G = H _G. And the total fuel demand Q
Is further increased, the balance rod 120 is moved to the position shown in FIG.
As shown in (D), the joint joint 122 is tilted so that the axial position of the oil amount adjusting rod 123 is controlled in proportion to Q ₀ = (Q−H _G ). If the total fuel demand Q decreases from this state, the balance rod 120
Moves both adjusting rods 123 and 124 in the direction of reducing fuel, but since the gas upper limit detector 146 is turned off, the positioner 125 moves the oil amount adjusting rod 123 to Q ₀ = α.
Pull back to ₀ . Therefore, the gas amount adjusting rod 124 is held at the upper limit value H _G position until Q ₀ = α ₀ is reached. Then, if reduced total fuel demand Q emptying it is below (H _G + α _0), the fuel distribution control is performed and returns to the initial oil quantitative mode III. The total fuel demand Q is (L _G
When it decreases to + α ₀ ) or less, the slip mechanism 109 operates and the mode is switched to the oil exclusive combustion mode I.

Thus, in oil metering mode III, FIG. 7 (B)
As shown in, when L _G ≤ Q _G ≤ H _G
Q ₀ = α ₀ and the gas injection amount Q _G = Q−α ₀ are controlled, and when Q _G <L _G , the mode is switched to the oil exclusive-fire mode I, and Q _G >.
When H _G , it is set to the gas quantitative mode and the gas injection amount
While maintaining Q _G at the upper limit value H _G , the oil injection amount Q ₀ is controlled according to (Q−H _G ).

As described above, according to the first embodiment, the following effects can be obtained.

1) That is, since the fuel distribution mode is divided into two simple modes, namely, oil exclusive combustion mode I, gas quantitative mode II, and oil quantitative mode III, it is easy to determine the mode corresponding to the fluctuation of the fuel supply condition. be able to. Further, since the mode setting means selectively sets those modes, and the quantitative setting means can set the quantitative setting value of the quantitative mode to an arbitrary value, which makes the mode setting operation extremely simple. be able to. And
Since the total fuel demand amount is automatically distributed to the two fuels by the fuel distribution means based on the set mode and the fixed set value, the fuel distribution is promptly performed in accordance with the two kinds of fuel supply conditions. You can change the mode,
The operation of the dual fuel diesel engine can be stably maintained according to the changed fuel distribution mode.

2) When the operation for switching to the mode using the fuel gas such as the gas fixed amount mode II or the oil fixed amount mode III is performed, the seal oil pump is automatically operated by the mode command output from the mode setting means, and the seal oil pressure is changed. Since the gas compressor is automatically operated when the pressure exceeds a predetermined pressure, the auxiliary equipment required for the gas use mode is automatically started, which simplifies the operation and reduces the oil-only combustion. In mode I, these auxiliary machines are automatically stopped, so that there are effects such as energy saving. Moreover, since the seal oil pressure and the fuel gas pressure are equal to or higher than the predetermined pressure is a gas use mode switching condition, the reliability of the operation of the fuel gas injection valve and the control of the fuel gas injection amount is ensured. There is. In addition,
Depending on the structure of the fuel gas injection valve, seal oil may be required even in a mode other than the gas use mode. In this case, the seal oil may be automatically operated by the diesel engine start command.

3) In the gas quantitative mode III of the quantitative set value α _G , in order to keep the variably adjusted oil injection amount Q _{0 above} the preset oil amount lower limit value β, the movement of the oil amount adjusting rod is changed. When the total fuel demand Q is reduced to (α _G + β) or less by regulating with a stopper, the slip mechanism causes the signal transmission between the governor output shaft and the oil amount adjusting rod and the gas amount adjusting rod to slip, and at the same time,
This slip is detected by the slip detector, and the mode is switched to the oil exclusive firing mode I. Therefore, the ignition stability of the fuel gas is ensured and the continuous (α _G + β)
There is an effect that stable operation control can be maintained by following the following total fuel demand amount Q.

4) In the oil fixed amount mode III of the fixed set value α ₀ , in order to maintain the injection amount Q _G of the fuel gas that is variably adjusted to the lower limit value L _G or more determined by the control characteristics of the fuel gas injection valve,
The movement of the gas amount adjusting rod is regulated by the lower limit setting device, and when the total fuel demand Q decreases to (α ₀ + L _G ) or less, the slip mechanism causes a gap between the governor output shaft and the oil amount adjusting rod and the gas amount adjusting rod. At the same time that the signal transmission of No. 1 is slipped, this slip is detected by the slip detector, and the mode is switched to the oil-only burning mode I which is excellent in the injection amount control characteristics in the small injection amount region. Therefore, even if a fuel gas injection valve with poor linearity of the injection amount control characteristic in a small injection amount region below a certain gas amount lower limit value L _G is used, when the gas injection amount Q _G becomes below that L _G , Even if the total fuel demand amount Q is reduced to a small injection amount region of (α ₀ + L _G ) or less, it is possible to maintain stable operation control by following the change even if the total fuel demand amount Q decreases to (α ₀ + L _G ). There is an effect that can be.

5) in an oil quantitatively mode III, for holding the fuel gas injection amount Q _G being variably adjusted below the gas amount upper limit value H _G being variably set, restricting the movement of the gas quantity adjusting rod by upper limit setting unit In addition, when the gas upper limit detector detects that Q _G = H _G has been reached, the oil amount adjustment rod is in the free state. Then, when Q _G <H _G again, the oil amount adjusting rod is restrained at the fixed set value α ₀ position. That is, holding the oil quantitative mode III, which is the setting mode when the gas injection amount Q _G is Q _G <H _G based on the gas amount upper limit value H _G, Q _G ≧ H gas injection amount Q _G when the _G Is automatically switched to the gas fixed amount mode fixed to H _G. Therefore, even when the maximum injection amount of fuel gas is limited to a predetermined or variably set upper limit value, there is an effect that stable operation control can be maintained over the entire load range. In particular, it is effective when the fuel gas, such as surplus gas and by-product gas, whose amount of generation fluctuates is effectively used.

6) Since the main part of the control device is realized by using a mechanical link mechanism, it can be installed in a high temperature atmosphere such as an engine room of a ship. In addition, since the working state of the main part can be seen at a glance, it is possible to easily find a failure and to easily perform maintenance such as repair and adjustment.

Next, a second embodiment of the present invention shown in FIG. 8 will be described. The second embodiment is realized by applying a computer instead of the link mechanism of the first embodiment, and the basic fuel distribution mode is the same as that of the first embodiment.

As shown in FIG. 8, the control device main body 800 is composed of a computer including input circuits 801, 802, CPU 803, memory 804, and output circuits 805, 806. The input circuit 801 includes a speed controller 81.
From 0 to the target rotation speed No, from the rotation speed detector 812 to the detected rotation speed N, from the fixed quantity setter 813 to the fixed set value α ₀ or α _G of the oil injection quantity Q ₀ or the gas injection quantity Q _G , the lower limit of the oil quantity is obtained. The oil amount lower limit value β from the setting device 814, the oil amount upper limit value H ₀ from the oil amount upper limit setting device 815, the gas amount lower limit value L _G from the gas amount lower limit setting device, and the gas amount upper limit value from the gas amount upper limit setting device 817. The value H _G is detected by the pressure detector 819 which detects the pressure of the fuel gas supplied to the fuel injection valve 2, and the detected pressure P
_G is also inputted with the detected pressure Ps from the pressure detector 818 which also detects the pressure of the seal oil,
These signals are converted into digital signals by the input circuit 801, and then stored in the memory 804 via the CPU 803. In addition, the CPU 803
From the mode setter 818 via the input circuit 802, the oil exclusive firing mode I, the gas quantitative mode II, the oil quantitative mode
One of the III mode command signals is input.

The CPU 803, based on these input data,
According to the flowcharts shown in FIGS. 9 to 12,
The total fuel injection amount Q, the oil injection amount Q ₀ , the gas injection amount Q _G, etc. were determined and connected to the control rack rods 6 and 7 of the fuel oil injection pump 4 and the control oil injection pump 5 via the output circuit 805, respectively. Positioner 821,822
In addition, the injection amounts Q ₀ and Q _G are output as analog signals. Further, the CPU 803 outputs an operation command to the start control device for the gas compressor and the seal oil pump via the output circuit 806.

The CPU 803 has an engine-related abnormality detecting unit 830.
That is, signals are input from the scavenging pressure detector 831, the exhaust pipe pressure / temperature detector 832, the gas leak detector 833, and the engine protection device 834 via the input circuit 801 or 802. Based on these input signals, an engine emergency stop command including fuel injection stop is output as necessary.

The control function and operation of the second embodiment thus configured will be described with reference to the flowcharts shown in FIGS.

These flow charts are a series, and only the main parts relating to the features of the present invention are shown, and are executed at every predetermined control cycle. When the starting condition is satisfied in step 900 and the diesel engine is started by the starting means (not shown) or the like, first, necessary data is taken in in step 902, and the load and the rotation speed are subsequently read in steps 904 to 910. The required total fuel amount Q is calculated. This calculation is performed by the function f ₁ defined in correlation with the target rotation speed N ₀ , and the basic fuel demand Q ₀
After calculating (step 904), the deviation ΔN between the detected rotation speeds N and N ₀ is calculated (step 906), and the corrected fuel amount ΔQ is calculated by the function f ₂ determined in correlation with ΔN.
Is calculated (step 908), and Q ₀ is corrected by this ΔQ to calculate the total required fuel amount Q (step 910).

Next, the routine proceeds to step 912, where it is determined whether or not the operation in which the load amount uses the fuel gas (hereinafter referred to as gas operation) is possible, and the value of Q is the oil amount lower limit value β that can secure the ignition stability. It is determined whether or not it is equal to or more than the sum of the gas amount lower limit value L _G (including 0) which is restricted from the control characteristics of the gas injection valve and the like. If this judgment is negative, gas operation is not possible, so the routine proceeds to step 914, where the oil exclusive combustion mode I is set,
Determine the oil injection amount Q ₀ to Q and the fuel gas injection amount Q _G to 0,
In step 916, the determined values Q ₀ and Q _G are output to the positioners 821 and 822, and the process returns.

The positioners 821 and 822 may be actuators that move linearly, such as piston cylinders. Feedback is provided to control the positions of the control rack rods 6 and 7 according to Q ₀ and Q _G , respectively. It consists of position control means with functions. Therefore, similar to the first embodiment, the fuel oil injection pump 4
The control oil injection pump 5 and, the Q _0, Q
Fuel oil and fuel gas controlled to _G (however, 0 in this case) are injected from the fuel injection valve 2 into the combustion chamber 3.

On the other hand, if the determination of whether or not the gas operation is possible in step 912 is affirmative, the process proceeds to step 920, and the mode command set and input by the mode setter 820 is fetched, and whether the mode command is I, II, or III. If it is the mode I, the process proceeds to step 914, and the oil-only burning mode I operation is performed according to the processing procedure described above.

If the determination in step 920 is II or III, the tenth
In steps 924 to 930 shown in the figure, the automatic operation of the auxiliary machines required for the gas operation and the completion of their startup are confirmed. That is, after outputting the automatic operation command to the start control device of the seal oil pump (step 924), the seal oil pressure Ps is set to the predetermined pressure Ps ₀ (for example, 280 kg / cm ²
It is set to g and stored in the memory 804. ) Wait for the above (steps 925 and 926). And Ps
When ≧ Ps ₀ , an automatic operation command is output to the start control device of the gas compressor (step 928), and then the fuel gas pressure P _G
Is set to a predetermined pressure P _G0 (for example, 250 kgcm ² g is set in the memory 8
It is stored in 04. ) Wait for the above (steps 929 and 930). Then, when P _G ≧ P _G0 is reached, the routine proceeds to step 932, and proceeds to step 934 of FIG. 11, and if the oil quantitative mode III, proceeds to step 950 of FIG.

In the case of the gas quantitative mode II, as shown in FIG. 11, depending on whether or not the total fuel requirement amount Q is equal to or more than the sum of the fuel gas quantitative fixed value α _G and the oil amount lower limit value β as shown in FIG. Determine if the gas metering mode II can be operated.

If this determination is affirmative, the process proceeds to step 936,
Based on the gas quantitative mode II, the gas injection amount Q _G is set to the quantitative set value α _G , and the oil injection amount Q ₀ is obtained as Q−α _G. Then, the process proceeds to step 938, it is determined whether the oil injection amount Q ₀ is equal to or less than the upper limit value H ₀ , and if the determination is affirmative, the fuel oil injection amount Q ₀ can be variably adjusted. Allocation is determined to Q ₀ and Q _G calculated in 936, and the determined values Q ₀ and Q _G are output to the positioners 821 and 822 in step 948, and the process returns.

On the other hand, if the determination in step 938 is negative, the process proceeds to step 942, where the oil injection amount Q ₀ is changed to the oil fixed amount mode III in which the upper limit value H ₀ is held, and based on this, the gas injection amount Q ₀ is changed. After determining _G to Q-H ₀ , the process proceeds to step 948 to output those determined values.

When the determination in step 934 is negative, the process proceeds to step 944, and the mode is changed to the oil fixed amount mode III in which the oil injection amount Q ₀ is kept at its lower limit value β, and the gas injection amount Q _G is changed to Q according to this mode. After determining −β,
Proceeding to step 948, those determined values are output.

In this way, even when the gas quantitative mode II is selected, depending on the conditions such as load and fuel usage,
As shown in FIGS. 13 (A) and 13 (B), modes I and I are automatically set.
I and III are selected, and stable operation control is maintained over the entire load range. Note that FIG. 7A shows an example in which only β is set, and FIG. 9B shows an example in which β, H ₀ , L _G , and H _G are all set.

In the case of the oil fixed amount mode III, the routine proceeds to step 950 shown in FIG. 12, where the value of the total fuel demand amount Q obtained in step 910 is the fixed set value α _{0 of} fuel oil and the lower limit value of fuel gas. Whether the gas operation in the oil fixed amount mode II is possible at present is judged by whether or not the sum of L _G or more. If this determination is affirmative, the process moves to step 952,
According to command mode III, set the oil injection amount Q ₀ to the fixed set value α ₀
Then, the gas injection amount Q _G is determined as Q-α ₀ . Subsequently, the routine proceeds to step 954, where it is judged whether or not the operation in the oil quantity determination mode III of the designated mode is possible depending on whether or not the obtained Q _G = (Q−α ₀ ) is less than the upper limit value H _{G of the} gas amount. When this determination is affirmative, the routine proceeds to step 956, where the distribution is decided to Q ₀ and Q _G obtained at step 952, and those decided values are decided at step 960 by the positioner 8
It outputs to 21,822. On the other hand, when the determination in step 954 is negative, the gas injection amount Q _G cannot be increased any more, so the process proceeds to step 958, and the mode is changed to the gas quantitative mode II in which Q _G is held at its upper limit value H _G , after the oil injection amount Q ₀ determined in Q-H _G in accordance with this mode, the positioner their determinations at step 960 821,82
Output to 2 and return.

If the determination in step 950 is negative, step 9
After shifting to 62, the gas injection amount Q _G is changed to the gas quantitative mode II in which the lower limit value L _G is held, and the oil injection amount Q ₀ is determined to Q-L _G according to this mode, and then the routine proceeds to step 960. Output those determined values.

As described above, even when the oil quantitative mode III is selectively set, as shown in FIGS. 13 (C) and 13 (D), it is automatically set according to the conditions such as the load and the amount of fuel used. Modes I, II and III are selected to maintain stable operation and control over the entire load range. FIG. 13 (C) shows an example in which only β is set, and FIG. 13 (D) shows an example in which all of β, Ho, Lg, and Hg are set.

In the case where the seal oil for the fuel injection valve 2 is required even in the oil-only combustion mode I regardless of the gas operation,
Steps 924-926 shown in the figure are step 9 in FIG.
It will be incorporated in steps before 00.

As described above, according to the second embodiment, the first
In addition to the same effects as in 1), 2), 3), 4), and 5) of the embodiment, the setting of quantitative set values, the upper and lower limit values, and the operation thereof can be performed very easily, so that the fuel is supplied. There is an effect that a fuel distribution pattern having a high degree of freedom can be set and controlled in response to the change in conditions. Further, as compared with the first embodiment, the mode setting means, the quantitative setting means,
The fuel distribution means can have a simple structure.

[Effects of the Invention] As described above, according to the present invention, the total required fuel amount to be supplied is gas-injected based on the gas fixed amount mode in which the gas injection amount is fixed and the oil injection material is variably adjusted according to the load. Amount and oil injection amount, and when the oil injection amount becomes a predetermined value or less as a result of the distribution, it is changed to the oil exclusive combustion mode and distributed, so ignition instability under load in gas quantitative mode operation Can be prevented and stable operation can be maintained.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a first embodiment of the present invention, FIG. 2 is a sectional view of a fuel injection valve of the first embodiment, and FIG. 3 is a fuel oil injection pump and a control oil injection pump of the first embodiment. FIG. 4 is an enlarged perspective view of the slip mechanism of the first embodiment, FIG. 5 is a detailed cross-sectional view of the positioner of the first embodiment, and FIGS. FIG. 7 (A) and FIG. 7 (B) are diagrams for explaining the operation of the first embodiment, and FIG. 8 is an overall block configuration of the second embodiment of the present invention. FIG. 9, FIG. 9 to FIG. 12 are flowcharts showing the main control procedure of the second embodiment, and FIG. 13 (A) to (D) are diagrams for explaining the operation of the second embodiment. 2 ... Fuel injection valve, 4 ... Fuel oil injection valve, 5 ... Control oil injection valve, 101 ... Governor, 108 ...
... fuel adjusting rod, 109 ... slip mechanism, 116 ... slip detector, 120 ... balance rod, 121, 1
22 ... Joint joint, 123 ... Oil amount adjusting rod, 1
24 ... Gas amount adjusting rod, 125, 126 ... Positioner, 139 ... Locking rod, 140 ... Cylinder stopper, 141 ... Gas amount upper limit setter, 142 ... Gas amount lower limit setter, 146 ... Gas Quantity upper limit detector, 150 ... Mode setting device, 151 ... Quantity setting device, 162,163 ...
... Pressure detector, 170 ... Switching drive, 800 ... Control device main body, 818 ... Seal oil pressure detector, 819
...... Fuel gas pressure detector, 813 …… Quantitative setting device, 81
4 ... Oil amount lower limit setting device, 815 ... Oil amount upper limit setting device, 816 ... Gas amount lower limit setting device, 817 ... Gas amount lower limit setting device, 820 ... Mode setting device, 821, 822 ...
… Positioner.

Claims (1)

[Claims] 1. A total fuel demand given is distributed to a gas injection amount and an oil injection amount based on a gas fixed amount mode in which the gas injection amount is fixed and the oil injection amount is variably adjusted according to the load. A control device for a dual fuel diesel engine, comprising fuel distribution means for changing to an oil-only combustion mode and distributing when the oil injection amount becomes a predetermined value or less.