JP2001090615A - Operation method for gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent uneconomical discharge of a gas from a relief valve for discharging a high pressure gas in order to prevent abnormal high pressure from acting on piping and an engine when a pressure adjusting valve arranged on a gas supply pipe from a gas bomb to the engine breaks. SOLUTION: When a pressure adjusting valve 6 breaks and a high pressure gas flows to a downstream side, the pressure is detected and a shielding valve 5 is closed. Then, the gas in the shielding valve 5 and forward is consumed at an engine 2 and the gas pressure is lowered to a normal pressure. Then the pressure is detected and the shielding valve 5 is opened. Emergency operation of the engine is continued by repeating such the opening and closing of the shielding valve 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A shutoff valve and a pressure regulating valve are installed in a gas supply path of a gas engine. When a failure occurs in the pressure regulating valve, an appropriate measure is required. The present invention belongs to such a technical field.

[0002]

2. Description of the Related Art In a fuel supply system of a gas engine, a shutoff valve for intermittently supplying high-pressure gas from a gas cylinder and a pressure regulating valve installed on the downstream side are installed as a minimum unit. The pressure regulating valve employed here is very common. That is, the minute opening degree of the regulating valve is adjusted by the balance between the diaphragm receiving the pressure of the high-pressure gas and the compression coil spring opposed thereto to reduce the pressure to the required pressure, and the reduced-pressure gas is supplied to the target location. If the function of the pressure control valve becomes abnormal and the pressure-reducing gas becomes high pressure, the relief valve connected to the pressure control valve is pushed open to prevent the abnormal high pressure from acting on the flow path. ing.

When the above-described gas engine is mounted on an automobile, the gas discharged from the relief valve is guided to a safe place such as a closed sectional space of a vehicle body.

On the other hand, the technique disclosed in Japanese Utility Model Laid-Open Publication No. Hei 7-23624 relates to a fuel supply circuit of a vehicle equipped with a fuel cylinder. The disclosed matter corresponding to the present invention is that the gas pressure in the cylinder is abnormal. This is a countermeasure technique when it occurs. That is, a safety valve is provided inside the main valve of the cylinder, and if the cylinder pressure becomes abnormal, the safety valve is opened to release gas into the atmosphere. In addition, the cylinder is provided with another safety valve, which also relieves into the atmosphere.

[0005]

In each of the above-mentioned prior arts, the relieved gas is not supplied to the engine, and wasteful processing is performed. In the case of an automobile, although being discharged to a safe place, it is an uneconomical treatment. Further, in Japanese Utility Model Laid-Open No. Hei 7-23624, since the gas is released into the atmosphere, the treatment is extremely uneconomical.

[0006]

SUMMARY OF THE INVENTION The present invention has been provided to solve the above-mentioned problems.
The basic idea is that the function of the relief valve is not performed in principle and the pressure value on the downstream side of the pressure regulating valve and the opening and closing of the shutoff valve are organically related. Another important point is that the shut-off valve has a pressure adjusting function.

According to a first aspect of the present invention, at least a high pressure gas shut-off valve and a pressure regulating valve disposed downstream of the shut-off valve are provided between the gas cylinder and the engine fuel supply device. When the gas pressure on the downstream side of the pressure regulating valve becomes abnormally high due to an obstacle to the regulating function of the regulating valve, the abnormally high pressure is detected and the shut-off valve is closed. When the pressure drops to a normal pressure or a value close to the normal pressure due to the consumption of the high-pressure gas, the pressure is detected, the shut-off valve is opened, and the shut-off valve is repeatedly opened and closed. It is characterized in that the temporary operation of the engine is continued with the gas present in the engine.

With this configuration, the shut-off valve is closed and the gas present between the shut-off valve and the fuel supply device is used for the operation of the engine. When the pressure decreases, the shut-off valve is opened and gas is supplied to the fuel supply device to continue the engine operation. In the case of an automobile engine, this corresponds to performing extraordinary traveling until the vehicle arrives at a repair shop. It should be noted here that the shut-off valve originally performs only the intermittent operation of the high-pressure gas from the gas cylinder. However, in the present invention, the shut-off valve also performs the function of pressure control necessary for the temporary operation. .

According to a second aspect of the present invention, in the first aspect, a relief valve is connected to the pressure regulating valve.
The valve opening pressure of the valve is set higher than the abnormally high pressure. Therefore, the intermittent operation of the shut-off valve becomes dominant, and the temporary operation is continued. When the pressure becomes abnormally high and must be relieved for some reason, the relief is taken as a safety measure. Is done.

According to a third aspect of the present invention, in the first aspect, the abnormally high pressure is lower than the valve opening pressure of the relief valve and has a pressure value that is not detrimental to the flow path structure on the downstream side of the pressure regulating valve. The normal pressure is characterized in that it is a pressure value on the downstream side of the pressure regulating valve during normal normal operation or a value near the pressure value.

Here, attention is paid to what kind of phenomena are set as abnormal high pressure and normal pressure. The abnormally high pressure is a pressure region lower than the valve opening pressure of the relief valve, and at the same time, a region where the flow path structure downstream of the pressure regulating valve is not damaged by high pressure. To avoid such damage, the set pressure of the pressure sensor is determined and means that such a pressure value must not be exceeded. The normal pressure is a pressure value on the downstream side of the pressure regulating valve during normal normal operation or a value close to the pressure value. If the normal pressure is reduced further, it impairs air-fuel efficiency and means that smooth operation is disturbed. ing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. FIG. 1 is an overall system diagram for implementing the method of the present invention, in the case of an automobile. The gas cylinder 1 stores natural gas at a high pressure in a gaseous state, and the gas cylinder 1 and the fuel supply device 3 of the engine 2 are connected by a supply pipe 4. In the middle of the supply pipe 4, a filter device, a control valve for gas filling, and the like are also installed. In the present invention, at least a high-pressure gas shut-off valve 5 and a pressure regulating valve 6 are arranged. The regulating valve 6 is located downstream of the shut-off valve 5.

A fuel supply device 3 attached to the engine 2
Although a type such as a mixer can be used, a fuel injection type is used here. A collecting pipe 7 is connected to the supply pipe 4, and a fuel injection nozzle 8 directed to an intake port of each cylinder is provided. A pressure sensor 9 for detecting the gas pressure on the downstream side of the pressure regulating valve 6 is attached to a part of the collecting pipe 7, and a detection signal therefrom is sent from the circuit 10 to the ECU. The signal calculated by the ECU according to the value of the pressure sensor 9 is output to the circuit 11.
And is sent to the solenoid type actuator 12 through.
The actuator 12 is a drive source for opening and closing the shutoff valve 5.

The primary function of the shut-off valve 5 is to shut off high-pressure gas from the gas cylinder 1 when the engine is stopped, and to shut off the gas cylinder 1 when the engine is running.
Is passed through the pressure regulating valve 6. To realize this, the ignition switch 1
3 is input to the ECU via the circuit 14, and the result is transmitted from the circuit 15 to the actuator 12.
Conveyed to. Note that reference numeral 21 indicates an ignition circuit.

The pressure regulating valve 6 has a built-in pressure reducing valve 16 and a relief valve 17. A branch pipe 18 connected to the downstream side of the pressure reducing valve 16 is connected to the relief valve 17. The pressure reducing valve 16 is a general one composed of a combination of a pressure receiving diaphragm, a compression coil spring opposed thereto, a control valve, and the like, as described in the section of the related art. When the relief valve 17 is pushed open for some reason, the high-pressure gas is released from the relief pipe 19. FIG. 1 shows the case of an automobile, so that the closed sectional space 20 of the vehicle body is used.
As a result, safety is ensured.

When the pressure on the downstream side of the pressure regulating valve 6 becomes abnormally high, it is necessary to warn of the abnormal pressure.
Is installed. That is, when the pressure sensor 9 detects an abnormally high pressure, the alarm 22 is activated via the ECU. When the pressure detected by the pressure sensor is between the abnormal high pressure H and the normal pressure L described later, a warning, for example, a lamp is kept on.

The relationship between the gas pressure on the downstream side of the pressure regulating valve and the opening / closing timing of the shut-off valve will be described with reference to FIG. For convenience of description, the expression “the downstream side” will be used hereinafter to mean the downstream side flow path of the pressure regulating valve 6. The shut-off valve is closed by the abnormally high pressure on the downstream side. The value H of this abnormally high pressure is set lower than the valve opening pressure of the relief valve 17, and the flow path system on the downstream side This is a value at which gas leakage does not occur from the connection joint or the like, in other words, a level at which excessive pressure does not occur in the flow path structure on the downstream side.

When the downstream pressure drops to a normal pressure or a value close to the normal pressure due to gas consumption of the engine, the shut-off valve is opened. The normal pressure L has a pressure difference such that a sufficient time can be secured before the shut-off valve 5 restarts, and
This is a value that allows engine operation to continue. The pressure at which the operation can be continued has a certain width with respect to the specific normal pressure L. This is because if the cylinder capacity of the engine is small even if it is slightly lower than the normal pressure L, the operation can be continued, and if the cylinder capacity is large, it is necessary to set it slightly higher than L. Under such circumstances "
··· Normal pressure or a value close to normal pressure ... ” Although the above description has been given with reference to the example of the cylinder capacity, the size of the space volume from the shutoff valve 5 to the fuel supply device 3 and the operating speed of the engine may also be related factors.

The operation of the above-described system will be described. If the adjusting function of the pressure adjusting valve 6 is impaired, for example, if the aforementioned diaphragm has a leak hole, the pressure reducing valve 16 remains open due to the tension of the compression coil spring. Flows to this is,
The pressure sensor 9 detects the abnormally high pressure and informs the ECU that the pressure is abnormally high. The ECU calculates the value and inputs it to the actuator 12 as a control signal. As a result, the shutoff valve 5 is closed and the abnormally high pressure on the downstream side is suppressed from further increasing. When such an abnormal situation occurs, the alarm 22 issues an alarm.

In parallel with the above suppression, the gas present in the flow path from the shutoff valve 5 to the fuel supply device 3 is consumed from the fuel injection nozzle 8 and the engine operation is continued. When the gas pressure on the downstream side decreases to near normal pressure with this gas consumption, this pressure value signal is transmitted from the pressure sensor 9 to the ECU. This is calculated by the ECU, and the signal is transmitted to the actuator 12 to open the shutoff valve. Thereby, the gas pressure from the shutoff valve 5 to the fuel supply device 3 is increased, and the continuous operation is maintained. As described above, the gas existing in the flow path from the shutoff valve 5 to the fuel supply device 3 is alternately repeated between the high pressure state and the normal state, so that the temporary operation under the warning condition is continued. This makes it possible for a car to be temporarily driven to a repair shop.

If the repetition is as described above, the relief valve 17 is opened and gas is not released. However, when the shut-off valve 5 is kept open for some reason, the gas pressure on the downstream side is reduced. May be significantly increased, and the flow path structure may be damaged. Therefore, a relief valve 17 is provided for the worst case.

FIG. 3 is a flowchart showing the operation described above. Here, PG is the gas pressure on the downstream side, and is shown as a reduced secondary pressure. In step S1, the PG is read by the pressure sensor 9, and if it is determined in step S2 that the initial P
If G is an abnormal pressure higher than KPGH (H in FIG. 2), the process proceeds to step 3 and the shutoff valve 5 is closed.
The closed state at this time is stored as FLAGV = 0.

Next, if the initial PG is abnormally high at a level lower than KPGH (H in FIG. 2) in step S2, that is, if the abnormally high pressure is at a level lower than the above-mentioned value. Go to step S4, PG and K
The relationship with PGL (L in FIG. 2) is checked, and it is determined whether or not it is in the high pressure range. As a result, PG is more KPG
If it is higher than L (L in FIG. 2), it is determined that it is in the high pressure range and the process proceeds to step S5, where the stored FLA
It is compared with the value of GV. As a result, if FLAGV = 0, the process proceeds to step S3, and the shutoff valve continues to be closed. on the other hand,
If it is determined in step S5 that FLAGV = 1, the process proceeds to step S6, and the cutoff valve continues to be opened.

As described above, when the gas consumption proceeds while the shut-off valve 5 is closed, PG and L are compared in step S4. If PG is still higher than L and the operation can be continued, step S5 is performed. Then, it is determined that the stored flag FLAGV is equal to 0, and the flow proceeds to step S3 to continue closing the shutoff valve.

When the gas consumption further progresses and PG drops near the normal pressure L, the process proceeds from step S2 to step S4, where it is determined that PG is lower than L.
Then, the process proceeds from step S4 to S6, and the shutoff valve 5 is opened. That is, the gas necessary for the continuation of the operation is supplemented.
At this time, FLAGV = 1 is stored. Then, P
When G reaches the pressure H, the above-described control flow is restarted.

By setting the pressure difference between H and L in FIG. 2, the gas existing between the shut-off valve 5 and the fuel supply device 3 can be consumed smoothly. That is,
After a suitable consumption time, the shut-off valve is opened and the gas is refilled. If the pressure difference between H and L is small or zero, the shut-off valve 5 is opened and closed little by little. Since it is not the frequency of opening and closing the valve, the shut-off valve may be broken. The opening / closing interval is not appropriate as the replenishment amount or consumption amount of gas with respect to the space volume between the shutoff valve 5 and the fuel supply device 3. In addition, as can be understood from FIGS. 2 and 3, in other words, the hysteresis operation is performed.

Although the structure and operation of the present invention are as described above, when numerical values such as pressure values are exemplified, the gas cylinder 1
0 Kg / cm 2, the relief valve opening pressure in FIG. 2 is 7 kg / cm 2, H in FIG. 2 is 6 kg / cm 2, and L is 3 kg / cm 2. The engine 2 has three cylinders of 1000 cc.

Although not described in the claims, the following matters can also be described in the claims. That is, in order to eliminate the harmfulness of the abnormally high pressure, the set pressure of the pressure sensor is set to be equal to or lower than the harmful pressure, and the shutoff valve is closed at a stage where the flow path structure is not damaged.

[0029]

According to the present invention, a pressure regulating valve is provided between a gas cylinder and a fuel supply device of an engine, wherein at least a high-pressure gas shut-off valve and a pressure adjusting valve are arranged downstream of the shut-off valve. When the gas pressure on the downstream side of the pressure regulating valve becomes abnormally high due to trouble in the valve adjusting function, the abnormally high pressure is detected and the shut-off valve is closed. When the pressure drops to a normal pressure or a value close to the normal pressure due to the consumption of the high-pressure gas, the normal pressure is detected, the shut-off valve is opened, and the shut-off valve is repeatedly opened and closed. This is a method of continuing the temporary operation of the engine with the gas existing on the road.

With the above-described method, the shut-off valve is closed and the gas present between the shut-off valve and the fuel supply device is used for the operation of the engine. When the gas pressure of the fuel supply device has decreased, the shut-off valve is opened to supply gas to the fuel supply device, and the engine operation is continued. In the case of an automobile engine, this corresponds to performing extraordinary traveling until the vehicle arrives at a repair shop. In particular, the shut-off valve originally only allows the high-pressure gas to be interrupted from the gas cylinder,
In the present invention, the function of pressure control required for the temporary operation is also achieved, and existing components are multifunctional to enable smooth temporary operation.

A relief valve is connected to the pressure regulating valve, and the valve opening pressure of the relief valve is set higher than the abnormally high pressure. Therefore, as in the prior art, if any trouble occurs, it is released immediately.
By opening the valve, it is possible to avoid releasing gas into the atmosphere, which is economical in terms of gas consumption. In the present invention, the intermittent operation of the shut-off valve is dominant, and the temporary operation is continued.
When the pressure becomes extremely high
Relief is provided as a safety measure, and the worst case of damaging the flow path structure can be avoided.

The value of the abnormally high pressure is lower than the valve opening pressure of the relief valve and is not detrimental to the flow path structure on the downstream side of the pressure regulating valve. It is the pressure value on the downstream side of the pressure regulating valve at the time or a value near the pressure value. In the present invention, it is important that the abnormal high pressure and the normal pressure are set based on what phenomenon. The abnormally high pressure is a pressure region lower than the valve opening pressure of the relief valve, and at the same time, a region where the flow path structure downstream of the pressure regulating valve is not damaged by high pressure. The pressure value that can avoid such damage is realized by selecting the set value of the pressure sensor. It also means that harmful pressure values must not be exceeded. The normal pressure is a pressure value on the downstream side of the pressure regulating valve during normal normal operation or a value close to the pressure value. The normal pressure has a certain width as described above. This means that smooth driving is disturbed due to hindrance. Since the pressure values on both the upper and lower sides are based on the above concept, the temporary operation is smoothly performed.

By setting the pressure difference between the set abnormal high pressure and the normal pressure, the gas existing between the shut-off valve and the fuel supply device can be consumed smoothly. That is, after an appropriate consumption time, the shut-off valve is opened and the gas is refilled. If this pressure difference is small or zero, the shut-off valve will be opened and closed in small increments, and the appropriate amount of gas replenishment and consumption with respect to the space volume between the shut-off valve and the fuel supply device will be obtained. Control cannot be taken. At the same time, the opening and closing of the shut-off valve in small increments may cause a failure of the shut-off valve.

[Brief description of the drawings]

FIG. 1 is an overall system diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing the opening / closing timing of a shutoff valve.

FIG. 3 is a flowchart of a shut-off valve control program.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gas cylinder 2 Engine 3 Fuel supply device 5 Shut-off valve 6 Pressure control valve 17 Relief valve

Claims (3)

[Claims] At least a shut-off valve for high-pressure gas and a pressure adjusting valve disposed downstream of the shut-off valve are provided between a gas cylinder and a fuel supply device of an engine. When the gas pressure on the downstream side of the pressure regulating valve becomes abnormally high due to the trouble, the abnormal high pressure is detected and the shut-off valve is closed, and then the abnormal high pressure is caused by the consumption of the high-pressure gas in the engine. When the pressure drops to a normal pressure or a value close to the normal pressure, the pressure is detected, the shut-off valve is opened, and the shut-off valve is repeatedly opened and closed. A method for operating a gas engine, comprising: continuing an extraordinary operation of the engine with gas. 2. The pressure regulating valve according to claim 1, wherein a relief valve is connected to the pressure regulating valve, and a valve opening pressure of the relief valve is set higher than the abnormally high pressure. How to operate a gas engine. 3. The abnormal high pressure according to claim 1, wherein the abnormal high pressure is lower than the valve opening pressure of the relief valve and is a pressure value that is not detrimental to the flow path structure on the downstream side of the pressure regulating valve. A method for operating a gas engine, comprising a pressure value on the downstream side of a pressure regulating valve during normal normal operation or a value near the pressure value.