JPS6026213Y2 - Dual fuel engine safety equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a safety device for a dual fuel engine that uses both liquid fuel and gaseous fuel, and is intended to prevent engine explosion due to gaseous fuel leaking into the crankcase.

By the way, this type of dual-fuel engine is primarily used as a land-use engine and is normally operated using gaseous fuel supplied from the outside, but in the event of an emergency when the supply of fuel is stopped, it can continue to operate using liquid fuel. This made it possible.

However, when the engine is operated on gaseous fuel, the fuel leaks from the combustion chamber into the crankcase, and if the concentration exceeds a certain level, there is a risk that the case may explode.

Therefore, in the present invention, the mist discharge device installed in the crankcase is equipped with a fan driven by a motor or the like to forcibly discharge the mist or leaked gaseous fuel to the outside of the engine room. If the fan stops due to a power outage, etc., it will automatically switch from gaseous fuel operation to liquid fuel operation.This will prevent the risk of gaseous fuel filling the crankcase, and will also be useful in emergencies such as power outages. The design allows the driver to continue driving safely even in

This will be explained below with reference to an embodiment shown in the drawings. In Fig. 1, 1 is an engine, 2 is a mist exhaust device installed in the engine, and this device is connected to the crankcase 3 of the engine and is led out of the engine room. It consists of a mist pipe 4, a chamber 5 for oil separation and recovery provided in the pipe, and a fan 6 for forced discharge, and is equipped with a motor 7 for driving the fan.

Reference numeral 8 denotes a sensor that generates a fan stop signal A when the fan 6 stops abnormally.
A slight differential pressure switch is used that detects the internal pressure of the fan and issues the signal A when the difference falls below a certain level, but there are also rotation sensors that detect the rotation of the fan,
It may also be a motor drive current sensor or the like.

In the illustrated embodiment, the mist pipe 4 is separated from the chamber 5, and the mist pipe 4 is separated from the engine side 4.
Since the opening end 4c' of the fan side pipe 4a is directed toward the outer surface of the end 4a' of the fan side pipe 4a, the mist discharged from the engine side pipe 4c once collides with the outer surface of the fan side pipe 4a. The mist is configured to flow into the fan side pipe, thereby effectively separating and recovering the oil contained in the mist.

Next, the operation of this embodiment will be explained with reference to the block diagram of FIG. 2. First, when a starting signal B is input during normal engine starting, this signal is transmitted as a liquid fuel operating signal C to various operating mode setting devices 11. For example, the on-off valve 11a on the gaseous fuel supply pipe is closed, the stop device 11b of the gaseous fuel pump is activated, and the gaseous fuel is set to 3 [provided to prevent excessive supply of combustion air during operation]. Liquid fuel pump discharge amount limiting device 11d for closing the on-off valve 11c on the bypass that communicates the discharge side of the supercharger with the suction side, and for supplying a small amount of liquid fuel necessary for ignition during gas/fuel operation. When each mode setting device is set to the liquid fuel operating state, such as by releasing the When a certain period of time set in the timer or delay circuit 12 has elapsed after the start signal B is applied, the gaseous fuel operation signal E is issued, and the operation mode setting device 11. The engine is switched to gas fuel operation by operating lla to lla to the opposite side, respectively, thereby completing the series of starting operations and returning to the normal operating state.

When the stop signal F is input when the engine is stopped, the liquid fuel operation signal G switches the operation mode setting device 11 to the liquid fuel operation state again, and after the time set in the timer or delay circuit 13 has elapsed, the liquid fuel operation is stopped. The signal H and the fan operation stop signal (2) are issued, the liquid fuel pump stop device 14 is activated, and the motor 7 is stopped, thereby ending the operation.

However, under normal operating conditions using the above gaseous fuel,
When the fan 6 stops due to a failure of the fan drive motor 7 shown in FIG. 1 or a power outage, the pressure difference between the upstream side 4a and the downstream side 4b of the fan in the mist pipe 4 decreases below a certain level. The sensor 8 detects this and generates a fan stop signal A, which is transmitted to the display device 15 as a display signal J as shown in FIG. At the same time, a liquid fuel operation signal K is sent to the operation mode setting device 11 to switch them to the liquid fuel operation state.In this way, when the fan stops abnormally, the engine operation mode is automatically changed to liquid fuel operation mode. In this embodiment, the fan start signal is issued at the same time as the engine start signal B is input, but this signal is sent to a timer or a delay circuit in the same way as the gaseous fuel operation signal E. By generating from the output side of 12,
The fan may be started when switching to gaseous fuel operation.

As described above, the present invention provides a dual fuel engine that uses both liquid fuel and gaseous fuel, in which a mist exhaust device installed in the crankcase is equipped with a fan for forced exhaust, and a sensor is installed to detect abnormal stoppage of the fan. Equipped with
Since the various operation mode setting devices are configured to switch from the gas fuel operation state to the liquid fuel operation state in response to the fan stop signal from the sensor, there is a risk of running the gas fuel operation with the fan stopped, that is, crank This prevents the risk of the case exploding due to gaseous fuel leaking into the case at a concentration above a certain level, and even in the event of an abnormality such as a failure of the fan drive motor or a power outage. This has the effect of making it possible to continue driving safely using liquid fuel.

[Brief explanation of the drawing]

FIG. 1 is an external side view of the vicinity of a mist discharging device in an embodiment of the present invention, and FIG. 2 is a block diagram showing the operation of the embodiment. 2 is a mist discharge device, 6 is a fan, 8 is a sensor, 11
is the operation mode setting device, A is the fan stop signal, and K is the liquid fuel operation signal.

Claims (1)

[Scope of utility model registration request] Forced υ [
In addition to being equipped with an output fan, it is also equipped with a sensor that detects abnormal stoppage of the fan, and the operation mode setting device is switched from a gaseous fuel operating state to a liquid fuel operating state in response to a fan stop signal from the sensor. Features a dual fuel engine safety device.