JP4441794B2 - Diesel engine - Google Patents

Description

  The present invention relates to a diesel engine, and more particularly, to a diesel engine that is required to have a short time until a load can be taken after a start is requested.

  The emergency diesel power generation facility is automatically started and stopped by a control signal such as a start signal or a stop signal. Also, it is required that the time from when the start signal is issued until the power can be used is as short as possible. For example, in the case of an emergency diesel power generation facility in a nuclear power plant, the power can be used in about 13 seconds. It is hoped that.

  In the case of starting, the starting electromagnetic valve is “opened” by the starting signal, and compressed air is supplied to the cylinder of the diesel engine. First, the diesel engine is rotated by the pressure of the compressed air supplied to the cylinder, and the rotational speed is increased to a rotational speed at which the temperature of the air compressed in the cylinder becomes a temperature at which fuel can be ignited. When the rotational speed rises above the rotational speed at which the temperature of the air compressed in the cylinder reaches a temperature at which the fuel can be ignited, fuel supply is started and the start solenoid valve is closed to stop the supply of compressed air To do. A diesel engine is provided with a fuel adjusting shaft that adjusts the amount of fuel supplied, and the amount of fuel delivered from the fuel injection pump varies depending on the rotational position of the fuel adjusting shaft. Is controlled accordingly.

  On the other hand, when the diesel engine is stopped, the stop solenoid valve is opened by the stop signal, and the compressed air is supplied to the stop cylinder equipped with the stop piston and provided in the diesel engine. When the compressed air is supplied to the stop cylinder, the stop piston moves to the rod side, and the lever fixed to the fuel adjusting shaft and protruding in the radial direction is pushed in the circumferential direction. By pushing the lever in the circumferential direction, the fuel adjusting shaft is rotated to the non-fuel supply position to cut off the fuel supply to the diesel engine and stop the diesel engine.

  In addition, if the supply of compressed air to the stop cylinder is shut off before the rotation of the diesel engine stops, if the speed governor accidentally increases fuel, fuel is supplied and the diesel engine is restarted. The supply of compressed air to the stop cylinder is continued until the diesel engine is completely stopped, and the stop piston is urged to rotate the fuel adjusting shaft to the fuel-free position until the diesel engine is completely stopped. It has become.

  After the diesel engine is completely stopped, the stop solenoid valve is `` closed '', the supply of compressed air to the stop cylinder is cut off, the pipe line between the stop cylinder and the stop solenoid valve, and the stop cylinder The residual pressure is gradually released to the atmosphere from an exhaust port provided in the stop cylinder. Therefore, immediately after the diesel engine stops, there is residual pressure in the pipe line between the stop cylinder and the stop solenoid valve and in the stop cylinder. For example, in the case of a 7200 HP diesel engine, it takes about 1 minute until the residual pressure disappears.

  There is an example disclosed in Patent Document 1 regarding the release of the residual pressure in an apparatus using compressed air. In the anti-lock brake system for a vehicle, when the brake is not operated, the pressure in the brake chamber is reliably reduced to the atmospheric pressure, and the braking force is reliably released.

JP-A-7-277166 (page 7, lines 11 to 32, FIG. 5)

  When a start signal is output immediately after the diesel engine is stopped, the engine is started in a state where there is residual pressure in the pipe line between the stop cylinder and the stop solenoid valve and in the stop cylinder. At the time of start-up, the governor as fuel control means tries to rotate the fuel adjusting shaft in the direction of fuel increase, that is, in the direction opposite to that at the time of stop. It is necessary to push back the stop piston which is in a state of being in contact with the. However, as described above, since there is a residual pressure in the pipeline between the stop cylinder and the stop solenoid valve and in the stop cylinder, when the stop piston is pushed back, the residual pressure is forcibly exhausted from the exhaust port. Thus, this becomes a resistance when the fuel adjusting shaft is rotated in the fuel increasing direction, and a smooth fuel supply operation is hindered.

  Therefore, when the diesel engine is started immediately after it is stopped, the fuel supply is insufficient until the residual pressure disappears, the rise of the rotational speed becomes slow at the beginning of the start, and the entire start time becomes longer.

  In the technique described in Patent Document 1, the residual pressure in the brake chamber is released to the atmosphere by the control valve at the same time that the brake pedal is released from being depressed. Unlike brake operation, there is no need for pressure adjustment. For this reason, the control valve described in Patent Document 1 is not provided, and the technique described in Patent Document 1 cannot be used.

  An object of the present invention is to enable a rapid start of a diesel engine even when a start signal is issued immediately after the diesel engine is stopped.

  The above-described problems of the present invention include a fuel control unit that controls the fuel supply amount by changing the position or posture of the fuel adjustment member, and operates independently of the fuel control unit driven by compressed air. Stop means for setting the position or posture to a position or posture for interrupting fuel supply, a stop compressed air pipe connected to the stop means for supplying compressed air, and a stop compressed air pipe interposed between the stop means and the stop A stop remote on-off valve that is opened by a signal to supply compressed air to the stop means and is closed when the diesel engine is stopped, and a stop compressed air pipe downstream of the stop remote on-off valve are provided. And a stop piston, which is coupled to the stop piston, and advances and retreats together. An operating rod, and when compressed air is supplied, the position or posture of the fuel adjusting member is set to a position or posture that interrupts fuel supply, and the fuel control means is provided after the diesel engine is stopped. When the engine is restarted, the fuel adjusting member is configured to move or change the position or posture of the fuel adjusting member in the direction in which the operating rod is retracted to increase the amount of fuel supply, and the atmosphere opening means includes the remote opening / closing valve for stopping Is achieved by a diesel engine configured to open the stop compressed air pipe downstream of the stop remote on-off valve to the atmosphere as the engine is closed.

  According to the above configuration, the stop remote on-off valve is opened by the stop signal and compressed air is supplied to the stop means, and the stop means to which the compressed air is supplied determines the position or posture of the fuel adjusting member according to the fuel supply. The position or posture to shut off. When the diesel engine whose fuel supply has been cut off is stopped, the stop remote opening / closing valve is closed, and at the same time, the atmosphere opening means opens the stop compressed air pipe downstream of the stop remote opening / closing valve to the atmosphere. Since the stop compressed air pipe communicates with the stop cylinder of the stop means, when the atmosphere release means opens the stop compressed air pipe to the atmosphere, the compressed air in the stop cylinder of the stop means is also compressed in the stop compressed air pipe. It is released into the atmosphere simultaneously with air. For this reason, when the diesel engine stops, the internal pressure of the stop cylinder quickly decreases to atmospheric pressure.

  Therefore, even when a restart instruction is issued immediately after the diesel engine is stopped, the fuel control means moves or changes the position or posture of the fuel adjusting member in the direction in which the operating rod is retracted for restart. To increase the fuel supply amount, the pressure in the stop cylinder is not hindered, and the diesel engine can be started quickly.

  It should be noted that the time during which the atmosphere releasing means opens the stop compressed air pipe to the atmosphere may be a preset time (for example, about 10 seconds) or until a stop signal or start signal is issued. The atmospheric release means is provided, for example, by branching to a stop compressed air pipe downstream of the stop remote on-off valve, and an atmospheric discharge pipe whose downstream end is opened to the atmosphere, and is interposed in the atmospheric discharge pipe. What is necessary is just to comprise including a remote on-off valve.

  According to the present invention, even when a start signal is issued immediately after the diesel engine is stopped, the diesel engine can be started rapidly.

  FIG. 1 shows the overall configuration of an emergency diesel generator according to an embodiment of the present invention. The illustrated emergency diesel generator includes a stop means 6 and connects a diesel engine 1 that drives a generator (not shown), an air storage tank (automatic) 2a, and a diesel engine 1 and an air storage tank (automatic) 2a. Y-strainers 9a and 9b and a starting solenoid valve 4a in order from the side closer to the air storage tank (automatic) 2a interposed in the starting compressed air tubes 13a and 13b, the starting compressed air tubes 13a and 13b. , 4b, check valves 8a, 8b, a communication pipe 17 communicating with the start compressed air pipes 13a, 13b on the downstream side of the check valves 8a, 8b, and a compressed air pipe for filling the air storage tank (automatic) 2a. 15, the air compressors 3 a and 3 b connected at 15, a check valve 8 d interposed in the filling compressed air pipe 15, and a filling compressed air pipe 15 on the downstream side of the check valve 8 d 16 is connected to an air storage tank (manual) 2b and an air storage tank (manual) ) A start compressed air pipe 14 connecting the communication pipe 17 to 2b, a stop valve 18 interposed in the start compressed air pipe 14, and a start compression between the Y-strainer 9b and the start solenoid valve 4b. A stop compressed air pipe 10 connecting the air pipe 13b and the stop means 6, and a stop remote opening / closing valve (hereinafter referred to as a stop solenoid valve) that is electromagnetically opened and closed interposed in the stop compressed air pipe 10 in order from the upstream side. 5a and 5b, and atmospheric discharge means attached to the stop compressed air pipe 10 on the downstream side of the stop solenoid valve 5b.

  The atmospheric discharge means includes an atmospheric discharge pipe 12 branched and connected to a stop compressed air pipe 10 on the downstream side of the stop electromagnetic valve 5b and the other end opened to the atmosphere, and an electromagnetic opening and closing interposed in the atmospheric discharge pipe 12. Remote open / close valve (hereinafter referred to as a pressure release valve) 11.

  As shown in FIG. 2, the stop means 6 includes a stop cylinder 6a, a stop piston 6b built in the stop cylinder 6a, and an operating rod 6c that is coupled to the stop piston 6b and moves forward and backward. The downstream end of the stop compressed air pipe 10 is connected to a stop cylinder 6a. An exhaust port is provided at a position near the cylinder head on the peripheral wall of the stop cylinder 6a.

  As shown in FIGS. 2 and 3, the pressure release valve 11 is attached at a position close to the stop cylinder 6a, and the axis is aligned with the stop compressed air pipe 10 connected to the stop cylinder 6a. It is desirable to install it. With the arrangement as shown in the figure, the resistance when releasing the residual pressure of the stop cylinder 6a from the pressure release valve 11 can be reduced, and the time required for releasing the residual pressure can be shortened.

  The diesel engine 1 is provided with a fuel adjusting member 7 that changes the amount of supplied fuel according to its position or posture, and the position or posture of the fuel adjusting member 7 is controlled by a fuel control means (not shown). . In the present embodiment, the fuel adjustment member 7 includes a fuel adjustment shaft 7a and fuel adjustment levers 7b1 and 7b2 that are fixed to the fuel adjustment shaft 7a and extend in the radial direction.

  The operating rod 6c of the stopping means 6 advances from the stopping cylinder 6a when compressed air is supplied to the stopping cylinder 6a, and its operating end abuts on the fuel adjusting lever 7b1 in the process of extending, and the fuel adjusting lever as it is. By pushing 7b1, the fuel adjusting lever 7b1 is moved to its non-fuel supply position, that is, a position where fuel supply is cut off. The fuel control lever 7b1 is in contact with the operating rod 6c of the stop means 6, and the fuel control lever 7b2 is separately provided at a position operated by the fuel control means.

  The start and stop of the diesel engine 1 are automatically performed by a control signal such as a start signal or a stop signal. In the state where the diesel engine 1 is stopped, the start solenoid valves 4a and 4b, the stop solenoid valves 5a and 5b, and the pressure release valve 11 are all “closed”. Hereinafter, the start and stop of the diesel engine 1 will be described with reference to FIGS. 2 and 3.

  In the case of starting the diesel engine 1, the start solenoid valves 4 a and 4 b are “opened” by the start signal, and the compressed air in the air storage tank (automatic) 2 a is supplied to the cylinder of the diesel engine 1. When the diesel engine 1 is initially started with the pressure of the compressed air supplied to the cylinder and the rotational speed rises above the rotational speed at which the temperature of the air compressed in the cylinder becomes a temperature at which the fuel can be ignited, The electromagnetic valves 4a and 4b are “closed”, and the supply of compressed air is stopped.

  When the diesel engine 1 is started, the fuel control means moves the fuel adjusting shaft 7a via the corresponding fuel adjusting lever 7b2, and controls the fuel supply amount according to the load. At that time, the fuel adjusting lever 7b2 is moved from the position of the fuel adjusting lever 7b2 at the time of stopping, that is, the fuel non-supply position, in the clockwise direction in the drawing, that is, the direction in which the fuel supply amount increases. At this time, the fuel control lever 7b1 corresponding to the operating rod 6c of the stop means 6 is also moved in the clockwise direction in the drawing, that is, in the direction in which the fuel supply amount increases. Accordingly, the fuel control lever 7b1 corresponding to the operating rod 6c moves in the clockwise direction while retracting the operating rod 6c. Since the stop cylinder 6a is provided with the exhaust port as described above, the operating rod 6c, that is, the stop piston 6b moves backward without resistance.

  When the diesel engine 1 is stopped, the stop solenoid valves 5a and 5b are "opened" by the stop signal, and compressed air is supplied from the air storage tank (automatic) 2a to the stop cylinder 6a. Due to this compressed air, the stop piston 6b moves toward the right side in the figure, and accordingly the operating rod 6c advances toward the right side in the figure. The actuating rod 6c abuts the corresponding fuel control lever 7b1 in the course of advancement, and moves as it is toward the right side in the drawing to rotate the fuel control lever 7b1 counterclockwise. When the fuel adjusting lever 7b1 comes to the non-fuel supply position, that is, the position where the fuel supply is cut off, the stop piston 6b reaches the limit of movement and stops.

  The stop cylinder 6a has an exhaust port as described above, and a part of the compressed air supplied to the stop cylinder 6a through the stop solenoid valves 5a and 5b is discharged from the exhaust port to the atmosphere. . However, even if a part of the supplied compressed air is discharged from the exhaust port, it is sufficient to apply the necessary force to the stop piston 6b, and there is no problem in the operation of the stop piston 6b.

  The fuel control means is also engaged with the corresponding fuel control lever 7b2, but the force applied by the stop piston 6b to the corresponding fuel control lever 7b1 is greater than the resistance force applied to the fuel control lever 7b2 by the fuel control means. Regardless of the operating state of the fuel control means, the stop piston 6b moves the fuel adjusting lever 7b1 to the non-fuel supply position.

  When the fuel adjustment lever 7b1 reaches the no-fuel supply position, the fuel adjustment shaft 7a rotates to a corresponding angle. The fuel control lever 7b2 fixed to the fuel control shaft 7a also rotates to the fuel non-supply position at the same time, and the fuel supply to the diesel engine 1 is shut off. By shutting off the fuel supply, the diesel engine 1 gradually decreases the rotational speed and stops.

  When the diesel engine 1 stops, a signal indicating that the diesel engine 1 has stopped is output from a sensor (not shown). Based on this signal, the stop solenoid valves 5a and 5b are "closed" and simultaneously the pressure is released. The valve 11 is “open”. When the pressure release valve 11 is "open", the stop compressed air pipe 10 on the downstream side of the stop solenoid valve 5b is opened to the atmosphere via the atmosphere release pipe 12 and the pressure release valve 11, and the stop solenoid valve The compressed air in the stop compressed air pipe 10 and the stop cylinder 6a on the downstream side 5b is released to the atmosphere.

  Since the stop cylinder 6a is provided with the exhaust port as described above, the compressed air in the stop cylinder 6a is also released into the atmosphere from this exhaust port. Therefore, after the diesel engine 1 is stopped, the compressed air in the stop compressed air pipe 10 and the stop cylinder 6a on the downstream side of the stop solenoid valve 5b is quickly released to the atmosphere, and the pressure in the stop cylinder 6a is reduced for a short time. At atmospheric pressure.

  The pressure release valve 11 is automatically “closed” after elapse of a predetermined time (about 10 seconds in the present embodiment) after being “open”. However, the pressure release valve 11 may be “closed” with a signal for opening the stop solenoid valves 5a, 5b.

  Next, a case where a start signal instructing restart is issued immediately after the diesel engine 1 is stopped in the above-described procedure will be described. At this time, even if the pressure in the stop cylinder 6a is reduced to the atmospheric pressure, the stop piston 6b is stopped in a state of moving to the limit toward the operating rod 6c, and the operating rod 6c is not supplied with fuel. It is in contact with the fuel adjusting lever 7b1 at the position. The fuel control lever 7b2 is also in the no fuel supply position.

  When a start signal for instructing restart is issued, the start solenoid valves 4a and 4b are opened, and the diesel engine 1 starts rotating by compressed air. Immediately after the stop, the diesel engine 1 is kept at a high temperature, so the air compressed by the cylinder immediately reaches a temperature at which the fuel can be ignited, and the fuel control means places the fuel control lever 7b2 in the fuel supply position for starting. Therefore, it is rotated clockwise in the figure. At this time, in order to rotate the fuel adjusting lever 7b2 clockwise in the figure, the fuel adjusting lever 7b1 fixed to the fuel adjusting shaft 7a to which the fuel adjusting lever 7b2 is fixed also needs to be rotated clockwise in the figure. Therefore, the stop piston 6b is pushed back to the cylinder head side via the operating rod 6c in contact with the fuel control lever 7b1.

  However, since the pressure in the stop cylinder 6a is reduced to atmospheric pressure in a short time after the diesel engine 1 is stopped, the load that pushes the stop piston 6b back to the cylinder head side impedes its operation for the fuel control means. do not become. That is, the fuel control means can operate the fuel adjusting shaft 7a so as to supply the fuel required for restarting the diesel engine 1 and increasing the rotational speed without causing a delay.

  In the above embodiment, the solenoid valve is used to open and close the compressed air pipe for starting, the compressed air pipe for stopping, and the atmospheric discharge pipe. However, the remote control is performed by a fluid pressure signal such as an electric signal or an air signal. Anything that can be used may be used. For example, it may be opened and closed with compressed air.

  FIG. 4 is a chart showing the rotational speed of the diesel engine 1 and the timing of various events and signals in the process of starting and stopping the diesel engine 1, with the time axis as the horizontal axis and the rotational speed as the vertical axis. When a start signal for starting a diesel generator (hereinafter referred to as D / G) is issued, the start solenoid valve is opened, and D / G starts rotating. When the rotational speed reaches about 1/3 of the rated rotational speed, the starting solenoid valve is “closed”. When the rotational speed reaches about 50% of the rated rotational speed, excitation of the generator is started and power generation starts. Approximately 10 seconds after the start signal is issued, the rotational speed reaches the rated rotational speed, and the generated voltage also becomes the rated voltage. At this stage, a load is applied to the D / G.

  When D / G is stopped, a stop signal is issued, the stop solenoid valve is “open”, and the fuel supply is shut off. When the fuel supply is cut off, the rotational speed of the D / G starts to decrease. Even if the fuel supply to the D / G is cut off, the rotation does not stop immediately but continues for a while due to the inertia of the engine. For example, in the case of 7200HP D / G, after the stop signal is issued and the fuel is shut off, the D / G continues for about 140 seconds. If fuel is accidentally supplied during this time, there is a risk of restart, so it is necessary to shut off the fuel by keeping the stop solenoid valve open until the rotation is completely stopped.

  When the restart request signal is output before the rotation stops after the fuel supply to the D / G is cut off, the stop solenoid valve is “closed” and the fuel supply is restarted. The rotational speed increases again.

  When a restart request signal is issued immediately after D / G stops, the starting solenoid valve is “opened” and D / G starts rotating. Since the cylinder is still hot immediately after the stop, the fuel control means immediately starts fuel supply. After the stop of D / G, the pressure release valve is "opened", the compressed air in the stop compressed air pipe 10 on the downstream side of the stop cylinder 6a and the stop solenoid valve 5b is released to the atmosphere, and the stop cylinder 6a The pressure has dropped to atmospheric pressure. Accordingly, the fuel supply by the fuel control means is performed with good timing, and the rotational speed of the D / G increases to the rated speed at the same speed as that at the normal start as shown by the curve (b) in the figure.

  Curve C in the figure shows an increase in rotational speed when restarting immediately after D / G is stopped when no pressure release valve is provided. As shown in the figure, the increase in the rotational speed is moderate at the initial stage of restart because the pressure in the stop cylinder 6a has not decreased to the atmospheric pressure. This is because the control of the shaft 7a is delayed and the increase in fuel supply is hindered.

  According to the above embodiment, as is clear from the comparison of the curve B and the curve C in the case where the pressure release valve is not provided according to the above embodiment, even when the start signal is output immediately after the diesel engine is stopped, The diesel engine could be started quickly.

1 is a system diagram showing a main configuration of a diesel engine according to an embodiment of the present invention. It is a cross-sectional schematic diagram which shows the detail of the part of embodiment shown in FIG. It is a cross-sectional schematic diagram which shows the state from which the part shown in FIG. 2 differs. It is a figure which shows the timing of the various events in the process of starting and a stop of a diesel engine, and a signal with the rotational speed on the vertical axis and the time axis on the horizontal axis.

Explanation of symbols

1 Diesel engine 2a Air storage tank (automatic)
2b Air storage tank (manual)
3a, 3b Air compressor 4a, 4b Start solenoid valve 5a, 5b Stop solenoid valve 6 Stop means 6a Stop cylinder 6b Stop piston 6c Actuating rod 7 Fuel adjusting member 7a Fuel adjusting shaft 7b1, 7b2 Fuel adjusting lever 8a, 8b, 8c, 8d Check valve 9a, 9b Y-type strainer 10 Stopped compressed air pipe 11 Pressure release valve 12 Atmospheric discharge pipe 13a, 13b, 14 Start compressed air pipe 15, 16 Filled compressed air pipe 17 Communication pipe 18 Stop valve

Claims (4)

Fuel control means for controlling the fuel supply amount by changing the position or attitude of the fuel adjusting member, and the fuel adjusting means driven by compressed air and operating independently of the fuel control means. A stop means for setting a position or posture to interrupt, a stop compressed air pipe connected to the stop means for supplying compressed air, and interposed in the stop compressed air pipe and opened by a stop signal and Compressed air is supplied to the stop means, and when the diesel engine stops, a stop remote on-off valve that is closed and an air release means provided on the stop compressed air pipe downstream of the stop remote on-off valve are provided. The stop means includes a stop cylinder, a stop piston built in the stop cylinder, and an operating rod coupled to the stop piston and advanced and retracted together. When the compressed air is supplied, the position or posture of the fuel adjusting member is configured to be a position or posture that cuts off the fuel supply. It is configured to increase or decrease the fuel supply amount by moving or changing the position or posture of the fuel adjusting member in the direction in which the operating rod is retracted, and the air release means instructs the closing of the stop remote on-off valve The diesel engine is configured to open the stop compressed air pipe downstream of the stop remote on-off valve to the atmosphere with a signal to stop. 2. The diesel engine according to claim 1, wherein the atmosphere opening means receives a signal instructing “closing” of the stop remote on-off valve, and then on the downstream side of the stop remote on-off valve for a predetermined time. A diesel engine configured to open a compressed air pipe for stopping to the atmosphere. 2. The diesel engine according to claim 1, wherein the air release means is configured to be “closed” by a start signal instructing start of the diesel engine. The diesel engine according to any one of claims 1 to 3, wherein the atmosphere release means is provided to branch to a stop compressed air pipe downstream of the stop remote on-off valve, and a downstream end is opened to the atmosphere. A diesel engine comprising an atmospheric discharge pipe and a remote on-off valve interposed in the atmospheric discharge pipe.

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