JPS6148621B2 - - Google Patents

Description

[Detailed description of the invention]

This invention is provided in a fuel supply system of a gas engine that uses fuel gas (hereinafter referred to as gas) as a main fuel and also uses ignition oil as a subsidiary fuel, and is capable of controlling the amount of ignition oil injected into the gas engine. This invention relates to an ignition oil injection amount control device for a gas engine. Generally, in this type of gas engine, the amount of ignition oil injected into the combustion chamber is determined by the amount of ignition oil injected into the combustion chamber when the gas engine is operating at full load (100% load factor), regardless of the load of the gas engine, that is, the magnitude of the output. The calorific value ratio of fuel consumption is set at around 10%. Therefore, although the amount of gas supplied increases as the load factor of the gas engine increases, the amount of ignition oil injected is always constant. Therefore, with this conventional gas engine fuel supply method, when the gas engine is operated at full load or high load, the ignitability of the air-gas mixture taken into the combustion chamber of the gas engine is poor. There is no problem with the combustion operation of the gas engine, but on the other hand, when the load factor of the gas engine decreases and the gas engine is operated at low load, the amount of gas supplied into the combustion chamber is significantly reduced, so the combustion There were disadvantages in that the ignitability of the air-gas mixture taken into the chamber became extremely poor and the combustion of the gas became unstable. By the way, according to experiments conducted by the inventor of the present application, in order to stably burn a gas engine from a low-load operating range to a high-load operating range, it is necessary to (expressed as a percentage of the total fuel consumption of gas and ignition oil)
It has been found that this is possible by increasing or decreasing in accordance with the load factor of the gas engine. Specifically, the 8th
For example, full load operation (load factor 100%) as shown in the figure.
When the ratio of the injection amount of ignition oil is 5 to 6%, and during intermediate load operation (load factor 25%), the value is 25 to 30%. The relationship between the load factor (%) is as shown in Figure 8.
Each line is represented by a straight line with a different slope after intermediate operation (load factor 25%). The present invention has been made in view of the above points, and the present invention continuously variably controls the injection amount of ignition oil in response to the detected fluctuations in the load factor of the gas engine. An object of the present invention is to provide an ignition oil injection amount control device for a gas engine that is capable of stabilizing the combustion of a gas engine from low to high load areas and optimizing the consumption of ignition oil. It is something. The structure of the present invention for achieving the above object is as follows:
This will be explained using FIGS. 1 to 6, particularly FIGS. 3 to 6, which correspond to embodiments. That is, the present invention operates in a diesel mode that mainly injects liquid fuel at startup, and normally uses gas fuel as the main fuel and liquid fuel for ignition. Disc cam 39 rotates forward and backward based on
and a push rod 40 which is moved up and down by the rotation of this disc cam 39, and which is pushed by this push rod 40 and interlocks with the up and down action of the push rod 40 and controls the amount of ignition oil injected by the ignition oil pump 2. an operating bar 45 that is coupled to the rack 2a and moves integrally therewith from the diesel mode position (FIG. 6A) to the gas mode position (FIG. 6B or C); A piston rod 3 protrudes from the side and clamps and temporarily holds the operating bar 45, which has been moved to the gas mode position, together with the push rod 40.
The power cylinder 33 has a power cylinder 33 having a power cylinder 4. According to the present invention, the disk cam 39 rotates in forward and reverse directions based on the output value of the gas engine, thereby causing the push rod 40 and the operating bar 45 to move up and down. Here, when the operating bar 45 is pushed up by the cam surface from the diesel mode position shown in FIG. 6A to the gas mode positions shown in FIGS. The rack 2a connected thereto operates so that the amount of ignition oil injected from the ignition oil pump 2 is reduced (DEC). At this time, the operation bar 45 is held down by the piston rod 34 protruding from the power cylinder 33, via the stopper rod 44 in the embodiment, and the push rod 40 is pressed down.
The rack 2a is also temporarily secured via the adjustment rod 42 to the gas mode position where the injection amount of the ignition oil is reduced.
Stable gas mode operation is performed. The present invention will be explained below with reference to an illustrated embodiment. First, with reference to the block diagram of FIG. 1 and FIG. 2, an outline of the configuration of a fuel supply system of a gas engine provided with an embodiment of the ignition oil injection amount control device 7 of the present invention will be explained. The ignition oil pump 2 is connected in parallel to the output section 4 of the engine governor 3, and the ignition oil pump 2 is configured to adjust the injection amount of ignition oil by operating the gas control valve 1 that controls the gas supply amount and the rack 2a. They are operated via a gas side transmission section 5 and an ignition oil side transmission section 6, respectively. An ignition oil injection amount control device 7 is provided between the ignition oil pump 2 and the ignition oil side transmission section 6 for controlling the stroke of the rack 2a in accordance with the load factor of the gas engine. On the other hand, on the operation side of the fuel supply system described above, there is an operation panel P that outputs start and stop signals for the gas engine to a control circuit 10, which will be described later, and a rotational speed of the gas engine corresponding to the operating stroke of the governor 3. , the above-mentioned ignition oil injection amount control device which detects operating elements correlated with the output of the gas engine, such as intake air amount and fuel injection amount, and inputs the corresponding output value to the control circuit 10 as the gas engine load signal Sp. an abnormality sensor 9 that detects overspeed, overheating, fuel leakage, etc. of the gas engine and inputs an abnormality signal Sn of the gas engine to the control circuit 10, and the output sensor 8 or abnormality sensor that constitutes the output sensor 7. a control circuit 10 that outputs a predetermined control signal Ss to the working air pressure generating mechanism 11 based on the signals Sp and Sn of 9;
It has a working air pressure generating mechanism 11 that sends working air to first and second cylinder devices 23 and 32, which will be described later. The control circuit 10 outputs a command signal Sq corresponding to the gas engine output signal Sp of the output sensor 8 to a step motor 36 constituting the ignition oil injection amount control device 7, which will be described later, as shown in FIG. At the same time, a rotation angle detection signal Sa from a rotation detector 37 for detecting the rotation angle of the step motor 36 is fed back to the control circuit 10. Next, the above configuration will be explained in detail with reference to FIG. (a) Output part 4 The output part 4 has an operating shaft 14 driven via a rod 13 by an output lever 12 of a governor 3 attached to the gas engine, and this operating shaft 14.
The accelerator crank 15 is held on a crankshaft 16 fixed to the tip of the accelerator crank 15. This accelerator crank 15 is rotatably attached to the crankshaft 16 at its intermediate position, and the crankshaft 16 and the accelerator crank 15 are connected to the operating shaft 14 by the drive of the governor 3.
Focusing on , increase force to the left of the drawing (FORCE)
The structure is such that it can be swung in the FEEBLE direction and to the right in the FEEBLE direction. (b) Gas side transmission section 5 The gas side transmission section 5 has one end connected to the lower end of the accelerator crank 15 via a rod 17, and the other end connected to the control lever 19 of the gas control valve 1 with a rod 18. The gas side transmission shaft 20 is connected to the gas side transmission shaft 20 via the gas side transmission shaft 20, and the gas side return lever 21 is fixed in the middle of the gas side transmission shaft 20. Further, on the left side of this gas side return lever 21, a gas side return lever 21 is provided.
A stopper 22 is provided. The mounting position of the stopper 22 is set so that the gas side return lever 21 comes into contact with the stopper 22 at a swing position corresponding to the CLOSE position of the gas control valve 1. Further, on the right side of the gas side return lever 21, a first cylinder device 23 is provided as a gas side operation biasing means for pushing the return lever 21 toward the stopper 22 side. (c) Ignition oil side transmission section 6 The ignition oil side transmission section 6 has one end connected to the upper end of the accelerator crank 15 via a rod 24, and the other end connected to the rod 25 and the dart pot type spring expander. A differential 26 consisting of
The ignition oil side transmission shaft 29 is connected to the accelerator lever 27 which is integrally connected to the adjustment lever 28 via the adjustment lever 28, and the ignition oil side transmission shaft 29 is fixed in the middle of the ignition oil side transmission shaft 29. It has a return lever 30. A stopper 31 of the ignition oil return lever 30 is provided on the left side of the ignition oil return lever 30 . The mounting position of this stopper 31 is set so that the ignition oil side return lever 30 comes into contact with the stopper 31 at a swing position corresponding to the decreasing position (DEC) of the ignition oil pump 2. Further, on the right side of the ignition oil side return lever 30, a second cylinder device 32 is provided as an ignition oil side operation biasing means for pushing the return lever 30 toward the stopper 31 side. (d) Ignition oil injection amount control device 7 The ignition oil injection amount control device 7 is shown in FIGS.
As shown in the figure, it consists of the above-mentioned output sensor 8 and operating means for controlling the stroke of the rack 2a of the ignition oil pump 2, which will be described next. This operating means is pushed by a power cylinder 33 operated by the working air generation mechanism 11 and a piston rod 34 of this power cylinder 33 and moved in a straight line together with a mounting base 35a, and has a stroke that presets the stroke of an operating bar 45, which will be described later. A step motor 36 driven by a setting stopper 35 and a command signal Sq output from the control circuit 10 when the gas engine output signal Sp from the output sensor 8 is input to the control circuit 10.
and a rotation angle detector 37 attached to the rotation shaft 36a to detect the rotation angle of the stepping motor 36 and feed back a rotation angle detection signal Sa to the control circuit 10; a clutch 38 that performs an on/off operation, a cam 39 attached to the rotating shaft 36a, and a roller 40b that is inserted through a retaining plate 40a and follows a cam surface 39a on the outer periphery of the cam 39.
a push rod 40 as a follower of the cam 39 which is linearly reciprocated along the direction of expansion and contraction of the piston rod 34, and a return spring which forcibly returns the rotating shaft 37 to the direction of rotation opposite to the direction of rotation of the stepping motor 36. 41, one end is fixed to a rack adjusting rod 42 connecting the rack 2a of the ignition oil pump 2 and the accelerator lever 27, and the other end is fixed to the guide rod 43.
The stroke setting stopper 35 is guided by a stopper rod 44 and a push rod 40 to adjust the ease.
and an operation bar 45 that can be pushed and operated as appropriate in the axial direction. The power cylinder 33 is configured such that the piston rod 34 is extended by the operation of the working air pressure generating mechanism 11. When the piston rod 34 is extended, it presses the stroke setting stopper 35, and in this state, the operation bar 4 is attached to the tip of the stopper rod 44.
5 is brought into contact, the stroke of the rack 2a corresponds to the intermediate load rate of the gas engine that allows the gas engine to operate in gas mode, for example, the intermediate load rate of 25%.
The injection amount of ignition oil is set to correspond to the amount of ignition oil. The injection amount of ignition oil corresponding to this intermediate load factor is, for example, 7 kg/ as shown in Figure 5A.
hr, and this value is indicated on the injection amount scale plate M by the setting pointer S. The set thickness d of the stroke setting stopper 35 is set depending on the output and displacement of the gas engine, and when a large amount of ignition oil is to be injected corresponding to the intermediate load rate (25%), the set thickness d
Just make it thicker. On the other hand, the torque of the stepping motor 36 is set to be larger than the resultant force of the cylinder output of the power cylinder 33, the torque of the return spring 41, and the tensile force of the differential gear 26. Next, the profile of the cam surface 39a of the cam 39 is represented by the cam diagram in FIG. This cam diagram has the rotation angle θ of the cam 39 as the horizontal axis.
3 is a diagram plotting the lift amount L of the push rod 40 and the ignition oil injection amount G on the vertical axis. FIG. In other words, when the cam rotation angle θ is in the range of 0° to 270°, the lift amount L of the push rod is, for example,
Increases linearly at 25/270, and cam rotation angle θ is 270
In the range from 0° to 300°, the slope is smaller than that in the range from 0° to 270°. When the cam rotation angle θ=270° (θ ₁ ), the lift amount L of the push rod is set to, for example, 25 mm as shown in FIG. 7, and when the push rod 40 is lifted by this set lift amount L ₁ , The operating bar 45, which is moved directly in accordance with this, is lifted to a position where it comes into contact with the stopper rod 44. Therefore, when the cam rotation angle θ=0, the cam surface 39a of the cam 36 is pulled by the differential 26 toward the injection amount increasing side (INC) of the ignition oil (OIL), and the gas engine is set to diesel mode (load factor 0 to 25%), and when the cam rotation angle θ = 270° (θ ₂ ), the operating bar 45 is lifted by the push rod 40 and the gas engine is set from diesel mode to gas mode. , and further from the cam rotation angle θ = 270° (θ ₁ )
= 300° (θ ₂ ), the operation bar 45 is further lifted to enter the gas mode (load factor 25-100%). Furthermore, the aforementioned gas side transmission shaft 20 and ignition oil side transmission shaft 29 are provided with a manual stop section 4 as a safety device in case the gas engine needs to be stopped immediately due to some inconvenience.
6 are connected via rods 47 and 48. This manual stop section 46 is configured to stop both transmission shafts 2 during normal operation.
When you release the handle 49 from the free position (FREE) and turn it downward to the stop position (STOP), the stop cam 50 rotates clockwise and the stop cam 50 pushes up. stop lever 5 which rotates both transmission shafts 20, 29 counterclockwise in the drawing via rods 47, 48.
1,52. Next, the operation of the above configuration will be explained. First, the user presses the start button on the operation panel P to output a gas engine start signal to the control circuit 10 to start the gas engine. At the time of starting, the load factor of the gas engine is low (25%
(below), gas engine load signal Sp as the detected load input from the output sensor 8 to the control circuit 10
The value of is low. Therefore, the control signal of the control circuit 10
The working air pressure generating mechanism 11 is actuated by Ss, and the first cylinder device 23 on the gas side is push operated, and the second cylinder device 3 on the ignition oil side is actuated.
2 is released, and at the same time, the power cylinder 33 of the ignition oil injection amount control device 7 is pushed. That is, the gas side return lever 21 is
Since the gas control valve 1 is pushed toward the stopper 22, the gas control valve 1 is in the closed position (CLOSE). In addition, the ignition oil side return lever 30 is in a free state and the distal end of the accelerator crank 15 is immovably fixed, so the crankshaft 16 is moved in the force increasing (FORCE) direction by the drive of the governor 3, so that the ignition oil side return lever 30 is in a free state. The oil pump 2 is held in the increasing position (INC), so that the gas engine is gradually increased in speed and set to a predetermined rotational speed. Furthermore, as the power cylinder 33 is operated by the push button, the stopper rod 44 is activated.
has been preset. Next, the control signal Ss of the control circuit 10 is again input to the operating air pressure generating mechanism 11, and the first cylinder device 23 on the gas side is released, and the second cylinder device 32 remains in the released state. It is in. That is, the gas side transmission shaft 20 is freely driven and operated by the governor 3, and the ignition oil pump 2 is in the increasing position (INC). And output sensor 8
As the detected load increases (0 to 25%), the gas control valve 1 gradually shifts to the OPEN position, and in conjunction with this, the gas engine load corresponding to the detected load of the output sensor 8 increases. The signal Sp is input to the control circuit 10, and the command signal Sq is input from the control circuit 10 to the stepping motor 36.
Clutch 38 enters. Therefore, the cam 39 is controlled by the stepping motor 36 so that the cam rotation angle θ is adjusted to 0 as the load factor of the gas engine increases (0 to 25%).
It is rapidly rotated from ° to 270 ° (θ ₁ ). From this, the cam 39 is pushed up against the differential 26 and the return spring 41 by the set lift amount _L1 until the operating bar 45 comes into contact with the stopper rod 44 via the push rod 40. The state shown in Figure B is reached. Therefore, the rack adjustment rod 42 is moved to the decreasing side (DEC), and the push rod 42 is moved to the decreasing side (DEC).
The moving pointer T, which moves in response to a lift amount of 0, is moved from the plus side of the scale plate M to the zero position side, and indicates the injection amount of ignition oil in proportion to the increase in the load factor of the gas engine. And finally, the fifth
As shown in Figure B, the moving pointer T is superimposed on the setting pointer S. That is, the gas engine reaches an intermediate load state (load factor 25%), switches from diesel mode to gas mode, and sets the set injection amount of ignition oil to 7 kg/hr. Incidentally, the rotation angle θ of the cam 39 is constantly detected by the rotation angle detector 37, and information on the rotation angle θ is sent through the control circuit 10 to appropriately control the rotation angle of the stepping motor 36. In addition, the gas engine load factor is 25% to 100%
(Gas mode) high load area, the governor 3
The operation further opens the gas control valve 1 and increases the amount of gas supplied. On the other hand, output sensor 8
Since the detected load increases, the stepping motor 36 is further rotated, and as the load factor of the gas engine increases (25 to 100%), the cam rotation angle changes from 270° (θ ₁ ) to 300° (θ _{2 ).} ). From this, the cam 39 is moved to the push rod 40.
Push up the operating bar 45 further by the set lift amount L ₂ against the differential 26, return spring 41 and power cylinder 33 through the
The state shown in FIG. 6C is reached. Therefore, the rack adjusting rod 42 is further moved to the decreasing side (DEC), and the movement pointer T is further moved from the set injection amount 7 kg/hr position on the scale plate M to the zero position side, as shown in FIG. 5C. The injection amount of ignition oil is shifted, and in proportion to the increase in the load factor of the gas engine, the injection amount of ignition oil is instructed, which is smaller than the set injection amount of 7 kg/hr, for example, 3 kg/hr. Next, the gas engine load factor changes from the high load factor area (25% to 100%) to the low load factor area (~25%) again.
Clutch 38 is released. Therefore, the cam 39 is reversely rotated by the torque of the return spring 41 and returns to the state where the cam rotation angle θ=0, and the operation bar 45 and the adjustment rod 42 are driven by the governor 3 to increase the amount of ignition oil. It will be returned to the INC. This causes the gas engine to return from gas mode to diesel mode. At this time, if the clutch 38 cannot be disengaged due to some failure, the stepping motor 36 may be rotated in the opposite direction to the normal rotation direction to forcibly return the loosening rod 42 to the increasing side (INC). Furthermore, when a stop command is issued from the operation panel P to the control circuit 10 while the gas engine is running, or when an abnormality signal Sn from the abnormality sensor 9 is input to the control circuit 10, the working air pressure generating mechanism 11 is activated. The first and second cylinder devices 23, 32 on the gas side and the ignition oil side are operated by push. That is, both the gas control valve 1 and the oil pump 2 are closed, the injection amounts of gas and ignition oil become zero, and the operation of the gas engine is stopped. The piston rod 34 of the power cylinder 33 is then retracted and the clutch 38 is released. Also, if you want to suddenly stop the operation of the gas engine due to some kind of accident while operating the gas engine, press down on the handle 49 and move it to the STOP side.The stop cam 50 will rotate clockwise in the drawing, and the gas side and ignition oil side will be rotated clockwise. Since the stop levers 51 and 52 are pushed up, both the gas control valve 1 and the ignition oil pump 2 are closed via the rods 47 and 48, and the gas engine is stopped. In this way, the injection amount of ignition oil can be continuously and variably controlled in response to fluctuations in the load factor of the gas engine detected by the output sensor 8, and the amount of ignition oil can be continuously variably controlled in response to fluctuations in the gas engine load factor detected by the output sensor 8. The combustion of the engine can be stabilized, and the amount of ignition oil to be injected can be set to an optimum amount that matches the load factor of the gas engine. By changing the shape of the cam 39 and the thickness of the stroke setting stopper 35, the injection amount of ignition oil when changing from diesel mode to gas mode can be adjusted as appropriate. As explained above, according to the present invention, the fuel supply system of a gas engine operates in a diesel mode mainly injecting liquid fuel oil when starting, and normally operates in a gas mode mainly injecting fuel gas. In the ignition oil injection amount control device installed in the ignition oil injection amount control device, the cam 39 operates the rack 2a that controls the ignition oil injection amount of the ignition oil pump 2 via the push rod 40 of the operation bar 45 connected to the rack 2a. Since the rack is operated in conjunction with the lifting and lowering operation based on forward and reverse rotation, the operation is more reliable and fine adjustment operation is possible, compared to the conventional method of operating the rack via a spring and a diaphragm. Further, when the operating bar 45 is moved together with the rack 2a to the gas mode position where the ignition oil injection amount is reduced by being pushed by the cam 39, the operating bar 45 is moved between the push rod 40 and the ston rod 34. I made it so that it could be clamped and temporarily fixed.
This has the effect of stabilizing combustion during normal gas mode and enabling operation with good thermal efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a fuel supply system equipped with an embodiment of the ignition oil injection amount control device for a gas engine according to the present invention, FIG. 2 is a perspective view of the same fuel supply system, and FIG. 4 is a side view of the ignition oil injection amount control device, and FIG. 5 shows the scale plate and pointer indicating the ignition oil injection amount. An explanatory diagram showing the positional relationship,
6A, B, and C are operation explanatory diagrams showing the operating states of the ignition oil injection control device corresponding to the states shown in FIGS. 5A, B, and C, and FIG. 7 shows the lift amount of the push rod and the cam rotation angle FIG. 8 is a graph showing the relationship between the ratio of the ignition oil injection amount to the gas injection amount and the load factor of the gas engine. 1... Gas control valve, 2... Ignition oil pump, 8...
...Output sensor, 33...Power cylinder, 35...
...Stroke setting stopper, 36...Stepping motor, 37...Rotation angle detector, 38...Clutch, 39...Cam, 40...Push rod,
41...Return spring, 42...Rack adjustment rod, 44...Stopper rod, 45...Operation bar.

Claims (1)

[Scope of Claims] 1. In a gas engine that operates in a diesel mode mainly injecting liquid fuel at the time of startup, and normally uses gas fuel as the main fuel and liquid fuel for ignition, the output value of the gas engine a disc cam 39 that rotates forward and backward based on the rotation of the disc cam 39; a push rod 40 that is moved up and down by the rotation of the disc cam 39; an operating bar 4 that is connected to a rack 2a for controlling the amount of ignition oil injected from the ignition oil pump 2 and moves integrally therewith from the diesel mode position to the gas mode position;
5, and a power cylinder 33 having a piston rod 34 protruding from the side opposite to the push rod 40 and clamping and temporarily fixing the operating bar 45, which has been moved to the gas mode position, together with the push rod 40. An ignition oil injection amount control device for a gas engine, characterized in that: