JPH062630A - Diesel engine emergency shutdown system - Google Patents

Abstract

PURPOSE:To check a fuel supply to a diesel engine as well as to make this engine be stopped emergently by installing a selector valve to be connected to each piping system at both intake and discharge sides of a fuel supply pump, and transferring this selector valve by means of an emergency stop signal. CONSTITUTION:This emergency shutdown system is provided with a fuel supply line 40 which pressurizes a fuel supply pump 20 and regulates the extent of pressure through a relief valve 60. Especially it is provided with a selector valve 90 to be connected to each piping system at both intake and discharge sides of the fuel supply pump 20, and this selector valve 90 is made so as to be transferred by an emergency shutdown signal. With this constitution, fuel oil remaining in the fuel supply line 40 of a diesel engine 10 is pumped out of the fuel supply pump 20, and fuel oil pressure in the fuel supply line 40 and a fuel branch pipe 70 goes down, and the fuel supply to the diesel engine 10 by the fuel pump 11 is stopped at once. Doing like this, the diesel engine 10 confronted to a suchlike emergency accident can be quickly stopped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine emergency stop device.

[0002]

2. Description of the Related Art A conventional emergency stop device for a diesel engine will be described with reference to FIG. 10 is a multi-cylinder diesel engine, 11 is a fuel pump provided for each cylinder, 1
2 is a controller for the discharge amount of the fuel pump 11, 13 is a controller 1
This is a link mechanism that transmits the signal No. 2 to the fuel pump 11.

Reference numeral 20 is a fuel supply pump, 21 is an electric motor for driving the fuel supply pump 20, 30 is a fuel tank, 40 is a fuel supply line, 50 is a fuel return line, 60 is a relief valve provided in the fuel return line 50, 70 is a fuel branch pipe. 80 is an emergency fuel expelling mechanism connected to the fuel supply line 40, 81 is a compressed gas pressure accumulator, and 82 is an external pilot switching valve.

Next, the operation of this apparatus will be described. Fuel oil pressurized by the fuel supply pump 20 and regulated by the relief valve 60 circulates in the fuel supply line 40 and the fuel return line 50 when the diesel engine 10 is operating normally. The fuel oil is supplied from the fuel branch pipe 70 to the fuel pump 11, and the amount corresponding to the command of the controller 12 is supplied to each cylinder by a known method. During such normal operation, the external pilot switching valve 82 of the emergency fuel expelling mechanism 80 is closed.

When an unexpected emergency occurs in the diesel engine 10 and the diesel engine 10 is brought to an emergency stop,
It is necessary to urgently shut off the fuel discharged from the fuel pump 11. In such a case, the diesel engine 10 has the controller 1
If 2 and the link mechanism 13 are operating normally, an emergency command from the controller 12 shuts off the discharge of fuel oil from the fuel pump 11 to make an emergency stop. However, in some cases, the controller 12, the link mechanism 13, or the fuel pump 11 system may have a malfunction, and the fuel oil discharge from the fuel pump 11 may not be urgently interrupted by the above method.

[0006] The most general method for coping with such a case is to shut off the power supply of the electric motor 21 to stop the fuel supply from the fuel supply pump 20, but for a while after that,
Fuel supply line 40, fuel return line 50, fuel branch pipe 7
0, the fuel oil remaining in the fuel pump 11, etc. is sucked and discharged by the fuel pump 11, so that the diesel engine 10 may not stop immediately and may cause a serious accident.

The emergency fuel expelling mechanism 80 is a technique for dealing with such a case. When the diesel engine 10 is urgently stopped, the electric power of the electric motor 21 is turned off to stop the fuel supply pump 20, and at the same time, the external pilot switching valve 82 is opened. The high pressure gas in the pressure accumulator 81 expels the fuel oil from the fuel supply line 40 to the fuel return line 50 to stop the diesel engine 10 early.

[0008]

The above-mentioned prior art has the following problems. In FIG. 3, the diesel engine 10 does not stop until the fuel oil remaining in the fuel branch pipe 70 is exhausted, so that a slight time lag occurs before the engine stops. It is an object of the present invention to provide an emergency stop device that can more quickly cut off the supply of fuel oil to a fuel pump in order to immediately stop a diesel engine that has encountered such an emergency accident. is there.

[0009]

[MEANS FOR SOLVING THE PROBLEMS] In a multi-cylinder diesel engine that operates with fuel oil pressurized by a fuel supply pump and regulated by a relief valve, a suction side piping system and a discharge side piping system of the fuel supply pump are provided. A switching valve connected to is provided, and the switching valve is switched at the time of emergency stop so that the fuel oil on the fuel supply line side flows back to the fuel tank by the fuel supply pump.

[0010]

In the emergency stop, by switching the suction side piping system and the discharge side piping system of the fuel supply pump, the fuel oil remaining in the fuel supply line of the diesel engine is sucked out by the fuel supply pump, and the fuel supply line and the fuel The fuel oil pressure in the branch pipe decreases, and the fuel supply to the diesel engine by the fuel pump is immediately stopped.

[0011]

Embodiments of the present invention will be described with reference to FIGS. In the figure, 10 is a diesel engine, 11 is a fuel pump, 12 is a controller, 13 is a link mechanism, 20 is a fuel supply pump, 21 is an electric motor, 30 is a fuel tank, 40 is a fuel supply line, 41 is a suction pipe and discharge. Pipe, 42 is discharge pipe,
50 is a fuel return line, 60 is a relief valve, 90 is a switching valve, and 91 is an emergency signal.

FIG. 1 shows a state in which the diesel engine 10 is operating normally. The fuel oil is sucked from the fuel tank 30 through the suction pipe 41 and the switching valve 90 to the fuel supply pump 20 driven by the electric motor 21, and is pressurized to the pressure set by the relief valve 60 to reach the fuel supply line 40. The amount is consumed in the diesel engine 10, and the surplus reaches the fuel tank 30 through the fuel return line 50 and the relief valve 60.

Next, consider a case where an unexpected abnormality occurs in the diesel engine and the engine is stopped urgently. In addition to a known method of issuing a command to the controller 12 to set the fuel discharge amount of the fuel pump 11 to zero upon detection of an abnormality, an emergency signal 91 is issued,
The switching valve 90 is switched to the position shown in FIG. Electric motor 21
Remains operational. The fuel oil in the fuel return line 50 from the fuel supply line 40 is sucked by the fuel supply pump 20, and is discharged from the suction pipe 41 to the fuel tank 30. In this case, the pressure in the pipe from the fuel supply line 40 to the fuel return line 50 is reduced, and the relief valve 60 is closed. Therefore, fuel oil is not supplied, and a vacuum is generated immediately, so that the fuel pump 11 is operated by the fuel pump 11. The diesel engine 10 stops because the fuel is cut off.

[0014]

In the conventional emergency stop device, even if an abnormal signal is output when an emergency is required, if the fuel pump control mechanism of the diesel engine does not operate, even if the fuel supply pump is stopped, the fuel in the fuel pipe will remain for a while. Is sucked into the fuel pump and supplied to the diesel engine, which may delay the stop of the engine and cause a serious secondary disaster.

The diesel engine emergency stop device according to the present invention is a diesel engine equipped with a fuel supply line that is pressurized by a fuel supply pump and regulated by a relief valve, and is connected to the suction side and discharge side piping systems of the fuel supply pump. By switching the switching valve by an emergency stop signal, the fuel oil in the fuel oil supply line is sucked in the reverse direction by the fuel supply pump, and the fuel supply to the diesel engine is blocked to prevent the diesel engine from being supplied. By having an emergency stop, it has the following effects.

After the abnormal detection, even if the fuel pump control mechanism does not operate due to the abnormal signal, the switching valve is switched by the same abnormal signal, and the fuel oil in the pipe reaching the fuel pump is sucked by the fuel supply pump, In order to instantly make a vacuum in the tube,
The fuel pump 11 immediately ceases to function, enabling a quick emergency stop of the diesel engine.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating a state during normal operation of a diesel engine incorporating an emergency stop device according to the present invention.

FIG. 2 is a configuration diagram showing a state of the diesel engine shown in FIG. 1 at the time of an emergency stop.

FIG. 3 is a configuration diagram of a conventional diesel engine emergency stop device.

[Explanation of symbols]

 10 Diesel Engine 11 Fuel Pump 20 Fuel Supply Pump 30 Fuel Tank 40 Fuel Supply Line 50 Fuel Return Line 60 Relief Valve 90 Switching Valve 91 Emergency Signal

Claims (1)

[Claims] 1. A diesel engine having a fuel supply line that is pressurized by a fuel supply pump and regulated by a relief valve, is provided with a switching valve that is connected to a suction side and a discharge side piping system of the fuel supply pump. By switching the valve by the emergency stop signal, the fuel oil in the fuel oil supply line is sucked in the opposite direction by the fuel supply pump, the fuel supply to the diesel engine is blocked, and the diesel engine is stopped urgently. A diesel engine emergency stop device characterized in that