JPS6132116Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a starting device for a dual fuel engine that uses both liquid fuel and gaseous fuel, and is designed to always start operation with liquid fuel at the time of starting.

By the way, this type of dual-fuel engine is primarily a land-based engine that is normally operated using gaseous fuel supplied from the outside, and in the event of an emergency or the like when the supply of fuel is stopped, it can continue to operate using liquid fuel. However, if the engine is suddenly started using gaseous fuel, the combustion condition becomes extremely unstable and the engine cannot start smoothly. Therefore, for this type of engine,
When starting up, it is customary to start operation using liquid fuel, but the devices that set the operation mode to liquid fuel operation mode or gaseous fuel operation mode include a shutoff valve on the gaseous fuel supply pipe, a pump for liquid fuel, and a gaseous fuel pump. If multiple devices are provided, such as a control device for the fuel pump and a bypass valve for the supercharger that controls the amount of combustion air supplied, all of these operation mode setting devices will operate in liquid fuel mode at startup. It is extremely troublesome to check that the settings are set to the correct conditions, and it is extremely troublesome to perform the starting operation even though all or part of the equipment is in the state required for gaseous fuel operation.
For example, when starting with gaseous fuel, the above-mentioned starting failure may occur, or there may be cases where the engine cannot be started at all.

The present invention addresses such problems in dual-fuel engines by equipping each operating mode setting device installed in each part of the engine with a state detection sensor, and using a signal from the sensor to control each of the above devices to The engine can only be started when it is confirmed that the engine is set to the state required for fuel operation.This prevents poor starting performance or starting errors caused by starting operation with gaseous fuel, and ensures that the engine always runs smoothly. It is designed to start at .

This will be explained below using an example shown in the figure.
In FIG. 1, 1 is a dual fuel engine, 2 is a supercharger installed in the engine, and an exhaust pipe 3 is connected to the turbine side of the supercharger.
An air supply manifold 5 is connected to the air delivery path 2a on the blower side via an intercooler 4, and a bypass 2c is provided between the air delivery path 2a and the air suction path 2b, and the bypass can be opened or closed. A bypass valve 6 is provided. 7 is a gas fuel supply pipe led to the engine from the outside, 8 is a shutoff valve provided on the pipe, 9 is a liquid fuel pump, and 10 is a gas fuel pump, both pumps each having a Control devices 11 and 12 are provided, and liquid fuel discharged from a liquid fuel pump 9 is supplied to the combustion chamber through a nozzle 13 installed in the cylinder head of each cylinder, and a gaseous fuel pump 10 is provided.
Hydraulic oil is discharged from the gaseous fuel supply pipe 7.
Gaseous fuel is supplied from the supercharger 2 to the combustion chamber together with combustion air by opening the gaseous fuel supply valves 14 installed at each confluence of the branching section 7a of the air supply manifold 5 and the branching section 5a of the air supply manifold 5. Reference numerals 15, 16, 17, and 18 are state detection sensors installed in the control devices 11 and 12 of the above-mentioned operation mode setting devices, that is, the bypass valve 6, the cutoff valve 8, and the control devices 9 and 10, respectively. In other words, the bypass valve 6 and the cutoff valve 8 are in a closed state, the control device 11 of the liquid fuel pump 9 is in a state where restrictions on the pump discharge amount are released, and the control device 12 of the gaseous fuel pump 10 is in the corresponding state. When the pump is in a state where its operation is stopped, each sensor generates start enable signals A, B, C, and D, respectively.

These startable signals A to D are input to the control circuit shown in FIG. 2, and when all startable signals A to D are input to the control circuit, they are input from the control circuit. A display signal that causes the display device 19 to display a message such as "Start ready" is output, and when a start command signal E issued by pressing the start button is input in this state, the control circuit activates a starter motor such as a starter motor. An activation signal is output to 20.

According to the above configuration, the bypass 2c of the supercharger 2
The bypass valve 6 provided on the gaseous fuel supply pipe 7 is closed so that the entire amount of discharge air of the supercharger required for liquid fuel operation is supplied to the air supply manifold 5, and the shutoff valve on the gaseous fuel supply pipe 7 is closed. 8 is closed to stop the supply of the fuel, and the control device 11 of the liquid fuel pump 9 releases the restriction on the pump so that the required amount of liquid fuel is supplied, and the gaseous fuel pump 9 In the case where the control device 12 of 10 has stopped the operation of the pump, each state detection sensor 15, 16, which detects these states, respectively.
Start enable signals A, B, C, from all of 17 and 18.
D is output, when the starting command signal E is issued, the starting device 2 is activated from the control circuit shown in FIG.
An activation signal is output to engine 0, which causes engine 1 to
will start. Therefore, engine 1 is
The required amount of combustion air and liquid fuel are supplied and the supply of gaseous fuel is stopped, that is, the engine is started with liquid fuel. Also, one of the control devices 11 and 12 of the bypass valve 6, cutoff valve 8, liquid fuel pump 9, and gaseous fuel pump 10 is in a state different from the above state, that is, in a state when performing gaseous fuel operation. If any of the start enable signals A to D is not output, even if the start command signal E is issued, the control circuit will not output the start device 2.
No activation signal is output to the engine 0, thereby reliably preventing starting with gaseous fuel or starting errors.

Furthermore, when an appropriate amount of time has elapsed since the start of startup using liquid fuel, a separately generated switching signal causes each of the above-mentioned operation mode setting devices 6, 8, 11, 12 to enter a state for gas fuel operation, i.e., the bypass valve 6 opens to return a portion of the discharge air of the turbocharger 2 to the intake passage 2b side to prevent excessive supply of combustion air during gas fuel operation, the shutoff valve 8 on the gas fuel supply pipe 7 opens to start supplying the fuel, the control device 11 of the liquid fuel pump 9 limits the discharge amount of the pump to only the amount required for ignition during gas fuel operation, and further the control device 12 of the gas fuel pump 10 releases the restriction on the pump to allow the required gas fuel to be supplied, and the engine is thereby transitioned to normal gas fuel operation.

As described above, in the present invention, each of the plurality of operation mode setting devices installed in each part of a dual fuel engine is equipped with a state detection sensor, and each operation mode setting device from the sensor is configured to perform liquid fuel operation. Since the engine is started by a signal indicating that the engine is in the state of It saves you the trouble of checking the status of the
This has the effect of preventing poor combustion conditions and starting errors caused by starting the engine with gaseous fuel, and ensuring that the engine is always started smoothly and reliably.

[Brief explanation of the drawing]

FIG. 1 is a layout diagram of various parts of an engine showing an embodiment of the present invention, and FIG. 2 is a circuit diagram of a control circuit in the embodiment. 1 is an engine, 2 is a supercharger, 7 is a gaseous fuel supply pipe, 9 is a liquid fuel pump, 10 is a gaseous fuel pump, 6, 8, 11, 12 are operation mode setting devices (6 is a bypass valve, 8 11 and 12 are pump control devices), 15 to 18 are state detection sensors, and 20 is a starter device.

Claims (1)

[Scope of utility model registration request] The operation mode setting device that sets the operation mode to either liquid fuel operation mode or gaseous fuel operation mode is equipped with a bypass valve that returns part of the discharge air of the supercharger to the suction side, and a bypass valve on the gas fuel supply pipe. In a dual fuel engine equipped with a shutoff valve, a control device for a liquid fuel pump, and a control device for a gaseous fuel pump, each of the operation mode setting devices is provided with a state detection sensor for detecting its state. At the same time, receiving the output signals of these sensors,
Each signal causes the bypass valve to close, the isolation valve to close, the liquid fuel pump controller to release the discharge restriction to the pump, and the gaseous fuel pump controller to stop operation of the pump. A starting device for a dual-fuel engine, comprising a control circuit that outputs an activation signal to the starting device when a separately issued starting command signal is input when the starting device indicates that the starting device is in the starting position.