JPH0886247A - Safety device for gas engine - Google Patents

Abstract

PURPOSE: To prevent the occurrence of abnormal combustion by providing a gas pressure regulator with a pressure sensor, and a load sensor for a gas engine, discriminating a value of the pressure sensor when a load exceeds a specified value, and reducing a load to prevent the occurrence of abnormality of an air-fuel ratio owing to abnormality of feed gas. CONSTITUTION: A mixer M is located at a stage followed by a supercharger T and a pressure of gas fuel fed to the mixer M is regulated through communication of an air pressure, present upper stream from the mixer M, with the air chamber of the diaphragm D of a gas regulator R through a balance line 1. Further, a pressure sensor S is arranged in the air chamber of the diaphragm D of the gas regulator R and a load sensor K for an engine is arranged as an intake air pressure sensor at an intake manifold 15. When the output of the load sensor K exceeds a specified value, the value of the pressure sensor S of the gas regulator R is discriminated, the presence of abnormality of a feed gas pressure is detected. When abnormality occurs to the feed gas pressure, the occurrence of abnormality is displayed by effecting control in such a manner that a generator output is reduced to a safe output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for preventing abnormal combustion occurring in a gas engine due to enrichment of an air-fuel ratio.

[0002]

2. Description of the Related Art In a conventional gas engine, the supply gas pressure is set higher than that of air, and even if the balance line is broken, the supply gas pressure is reduced, the air-fuel ratio is diluted, and an abnormality occurs. Since the air-fuel ratio moves in the direction in which combustion is unlikely to occur, the need for safety equipment was not recognized.

[0003]

SUMMARY OF THE INVENTION In a gas engine, the present invention reliably determines an abnormal air-fuel ratio when a balance line is broken, and detects an abnormal air-fuel ratio of a mixer due to an abnormal pressure adjustment of a gas regulator. A safety device is provided to prevent the occurrence of combustion.

[0004]

The problems to be solved by the present invention are as described above. Next, the means for solving the problems will be described. The gas engine according to claim 1, wherein the gas pressure regulator is provided with a mixer before the supercharger, and the gas pressure supplied to the mixer is corrected by the air pressure upstream of the mixer. By providing S and a load sensor K of the gas engine, and by determining the value of the pressure sensor when the load is equal to or greater than the specified load, the load is reduced to avoid the air-fuel ratio abnormality due to the abnormality in the supply gas pressure. Is.

According to a second aspect of the present invention, in the gas engine configured such that a mixer is provided in front of the supercharger and the gas pressure supplied to the mixer is corrected by the air pressure upstream of the mixer. A flow switch is installed at the air pressure outlet, and a load sensor K for the gas engine is installed to determine whether or not the flow switch is operating at a specified output or higher, thereby determining the air-fuel ratio caused by the abnormal supply gas pressure. The load is reduced in order to avoid an abnormality.

In the present invention, each bank is provided with a supercharger, a mixer is provided in front of the supercharger, and the mixer has one
In a V-type supercharged gas engine that branches and supplies the gas regulated by two gas regulators, take out the air pressure from the upstream of each mixer and join them just before the gas regulators.
Connect to the gas regulator air chamber, install a flow switch F at the air pressure outlet of each mixer, install a load sensor K of the gas engine, and operate the flow switches FL and FR of both banks simultaneously at the specified pressure abnormality. By determining whether the air-fuel ratio is abnormal or not, the load is reduced to avoid the air-fuel ratio abnormality due to the abnormality in the supply gas pressure.

In the present invention, each bank is provided with a supercharger, a mixer is provided in front of the supercharger, and the mixer has one
In a V-type supercharged gas engine that branches and supplies the gas regulated by two gas regulators, take out the air pressure from the upstream of each mixer and join them just before the gas regulators.
The gas pressure is corrected by the average value of the air pressure upstream of the mixer.

[0008]

Next, the operation will be described. According to claims 1, 2, and 3, it is possible to prevent the air-fuel ratio from becoming rich due to the damage of the diaphragm D and the abnormal combustion due to the enrichment. Further, it is possible to prevent enrichment of the air-fuel ratio and abnormal combustion due to breakage of the balance line 1.

According to claim 4, each bank is provided with a supercharger, a mixer is provided in front of the supercharger, and the gas regulated by one gas regulator is branched to the mixer. In the V-type supercharged gas engine to be supplied, the air pressure is taken out from the upstream of each mixer and merged immediately before the gas regulator, and the gas pressure is corrected by the average value of the air pressure upstream of the mixer. A constant air-fuel ratio characteristic is obtained regardless of the increase in pressure loss over time. Further, even if the pressure loss varies among the air filters between the banks, the average air-fuel ratio can be kept constant, so that abnormal combustion does not occur.

[0010]

EXAMPLES Next, examples will be described. 1 is a drawing showing a fuel supply system and a control circuit in a gas engine, FIG. 2 is a drawing showing a flow chart of the control circuit of the present invention, and FIG. 3 is a gas engine safety device of the present invention, showing an air-fuel ratio with respect to an intake filter pressure loss. Drawing showing the relationship of mixer differential pressure, FIG.
FIG. 5 is a drawing showing changes in gas regulator air chamber pressure and fuel air-fuel ratio with respect to engine output in the safety device for a gas engine of the present invention. FIG. 5 shows a gas provided with a flow switch F at an air pressure outlet upstream of the mixer. FIG. 6 is a drawing showing a fuel supply system and a control circuit of the engine safety device, and FIG. 6 is a flowchart showing the gas engine safety device of FIG.

FIG. 7 is a drawing showing a fuel supply system and a control system of a safety device for a gas engine attached to a V-type supercharged gas engine, which branches and supplies gas regulated by one gas regulator, and FIG. FIG. 9 is a drawing showing a flow chart of the control device of FIG. 7, and FIG. 9 is also a V-type supercharged gas engine for branching and supplying gas whose pressure is regulated by one gas regulator, and extracting air pressure from the upstream of each mixer, A drawing showing a fuel supply system and a control system of a safety device of a gas engine that merges immediately before a gas regulator and corrects the gas pressure with an average value of the air pressure upstream of the mixer, and FIG. 10 shows the progress in the control of FIG. 9. It is drawing which shows the mixer inlet air pressure, the mixer differential pressure, and the change of an air fuel ratio with respect to time.

The invention of claim 1 will be described with reference to FIGS. 1, 2, 3, and 4. As fuel for engine E,
A mixture of gas fuel and air in the mixer M is supplied as fuel gas from the intake manifold 15 to the combustion chamber. The air is filtered by the air filter 13 and supplied to the mixer M. The fuel gas is the gas regulator R
Adjusted via the variable valve V,
It is supplied to the mixer M. Air pressure is taken out from the mixer M by the balance line 1 and is supplied to the air chamber of the diaphragm D constituting the gas regulator R, and the gas regulator R can change the flow rate of the fuel gas. The variable valve V is a valve that is provided in the fuel gas supply circuit to the mixer M and optimizes the fuel gas pressure while automatically controlling.

The fuel gas mixed by the mixer M is compressed by the compressor 3 of the supercharger T, passes through the intercooler 4 and the throttle 5, and is then taken into the intake manifold 1.
5 is supplied to the combustion chamber. A load sensor K is arranged in the intake manifold 15. Further, a part of the fuel gas is taken out from the pipe in front of the gas regulator R, and the gas fuel is supplied to the pre-chamber via the gas compressor 8 and the cooler 7 driven by the motor 9 to facilitate ignition. There is. Reference numeral 10 is a gas fuel regulator for the pre-chamber, and 12 is a check valve at the pre-chamber inlet.

Exhaust gas from the combustion chamber of the engine E is supplied to the turbine 2 of the supercharger T from the exhaust muffler 6. The compressor 3 is rotated by the rotation of the turbine 2. A thermo sensor 16 is arranged at the exhaust muffler 6. The thermo sensor 16, the load sensor K, the pressure sensor S, and the rotation speed sensor 1
A signal from 1 or the like is transmitted to the controller C, and the controller C makes a determination and transmits the signal to the control panel.

In the overall structure as described above, the supercharger T
Is provided in front of the mixer M, and the pressure of the gas fuel supplied to the mixer M and the air pressure upstream of the mixer M are adjusted to the balance line 1
It is adjusted by communicating with the air chamber of the diaphragm D of the gas regulator R via. A pressure sensor S is provided in the air chamber of the diaphragm D of the gas regulator R. Further, the engine load sensor K is provided in the intake manifold 15 as an intake pressure sensor. The load sensor K is not limited to being provided in the intake manifold 15, and may be attached to a generator to serve as a power generation amount sensor.

When the load sensor K exceeds the specified output, the value of the pressure sensor S of the gas regulator R is discriminated to detect whether or not the supply gas pressure is abnormal. If the supply gas pressure is abnormal, the control panel of the engine E is displayed to indicate that the pressure is abnormal, and the output of the generator is controlled to be reduced to a safe output.

Referring to FIG. 2, a control flowchart of the safety device for a gas engine of the present invention will be described. First, it is determined whether the engine E is rotating. Next, the load of the engine E is detected by the load sensor K, and the gas regulator R
The pressure of S is detected by the pressure sensor S, and it is determined whether these are normal. It is judged whether there is any abnormality last time. Regardless of whether there is any abnormality last time, it is determined whether or not load ≧ specified value, and then it is determined whether pressure ≧ specified value. If the load and pressure are abnormal due to this, the governor deceleration operation is performed and the air-fuel ratio abnormality is displayed. If it is not abnormal, the load control by the governor is continued.

This will be described with reference to FIG. In FIG. 3, the horizontal axis represents the pressure loss of the intake filter. The increase in the pressure loss of the intake filter means that the supply amount of air increases. That is, the horizontal axis of FIG. 3 can be regarded as the air supply amount. When the balance line 1 operates normally and the automatic control operates normally, both the air-fuel ratio and the mixer differential pressure maintain a constant value as shown by the dotted line in FIG. 3 when the balance line is normal. Then
It should not change. However, when an accident such as breakage of the diaphragm D of the balance line 1 or breakage of the pipe of the balance line 1 actually occurs, the mixer differential pressure increases according to the amount of air supplied, and the air-fuel ratio decreases. It happens.

FIG. 4 shows the state of the air-fuel ratio with respect to the output of the engine and the change in the air chamber pressure of the gas regulator R. That is, in terms of the air-fuel ratio, the air-fuel ratio is usually a lean air-fuel ratio as shown at the rated operating point m. With this air-fuel ratio, even if the output is increased, the knocking region X hatched is hatched. It is impossible to enter. But,
When the balance line 1 is damaged and the air-fuel ratio moves from lean to rich to reach the air-fuel ratio at the fault operating point n, if the output is increased at this air-fuel ratio n, the knocking range X drawn with diagonal lines is drawn.
Enter (n '). This causes knocking and damages the engine.

The lower part of FIG. 4 shows changes in the air chamber pressure of the gas regulator R with respect to the output of the engine E. When the balance line 1 is not in failure, the pressure in the air chamber of the gas regulator R gradually decreases as the output increases. However, when the balance line 1 is out of order, the pressure in the air chamber of the gas regulator R remains at atmospheric pressure and does not change. Therefore, the state in which the output does not change is determined from the time of the determination start output, and the output is reduced.

The embodiment of the safety device for a gas engine shown in FIGS. 5 and 6 is constructed as follows. That is, the mixer M is provided in front of the supercharger T, and the air pressure upstream of the mixer M is connected to the air chamber of the gas regulator R by the balance line 1. Further, in the present invention, a flow switch F is provided at the air pressure outlet on the upstream side of the mixer M. In addition, the load sensor K of the engine E is separately provided, and the rotation speed sensor 11 and the thermo sensor 16 are provided in the same manner.

With the above configuration, when the output of the engine E is equal to or higher than the specified output, it is determined whether or not the flow switch F is operating, and the presence or absence of pressure correction abnormality of the gas regulator R is detected. If the pressure correction of the gas regulator R is abnormal, the abnormality is displayed on the control panel of the engine E, and the output of the generator is controlled to be reduced to a safe output.

In FIG. 6, a flow chart of the control device of FIG. 5 is shown. Then, the load of the engine E is detected, the state of the flow switch F is monitored, and when the load exceeds the specified value and the flow switch F operates, it is determined that an abnormal state has occurred, and the governor deceleration operation is performed. Then, the abnormality of the air-fuel ratio is displayed on the control panel.

FIG. 7 discloses a V-type supercharged gas engine in which a gas regulated by one gas regulator is branched and supplied. Fuel gas is the primary gas regulator R1
After the pressure is adjusted by the secondary gas regulator R2, it is branched into the left bank balance line 1L and the right bank balance line 1R and supplied to the mixers ML and MR. The mixer ML
The air pressure is taken out from the upstream side of the MR, and is connected to the air chamber of the diaphragm D of the secondary gas regulator R2 immediately before the secondary gas regulator R2.

Flow switches FL and FR are arranged at the air pressure outlet. For the engine E, an intake pressure sensor or a power generation sensor
The load sensor K is configured. Above the specified output,
Moreover, it is determined whether or not the flow switches FL and FR of both banks are operating and whether or not there is any abnormality in the pressure correction of the gas regulator R is detected. When there is an abnormality in the pressure correction, the abnormality is displayed on the engine control panel and the output of the generator is reduced to a safe output. FIG. 8 discloses a flowchart for controlling the safety device of the gas engine of FIG. 7.

In FIG. 9, a supercharger is provided in each bank, a mixer is provided in front of the supercharger, and the gas whose pressure is adjusted by one gas regulator is branched and supplied to the mixer. Disclosed is a V-type supercharged gas engine safety device for a gas engine, in which air pressure is taken out from the upstream of each mixer and merged immediately before a gas regulator to correct the gas pressure with an average value of the air pressure upstream of the mixer. Has been done. Although the structure is substantially the same as that of FIG. 7, the controller C is not provided and the flow switch F is not provided.

In the configuration of FIG. 9, when a difference occurs in the pressure loss of the air filters of the left and right banks, a difference occurs in the air pressure at the inlets of the left and right mixers ML and MR, and the right bank balance line 1R and the left bank. An air flow is generated between the balance lines 1L. At the confluence of the secondary gas regulator R2, the inlet air pressure of the left and right mixers ML and MR has an average value, and the supply gas pressure has a value corresponding to the average air pressure. As shown in FIG. 10, the mixer ML
The air-fuel mixture formed by the MR shifts leanly on one side and densely on the other side, but merges at the inlet of the supercharger T.
The air-fuel ratio after merging is kept constant.

[0028]

Since the present invention is constructed as described above, it has the following effects. In a gas engine according to claim 1, wherein a mixer is provided before the supercharger and the gas pressure supplied to the mixer is corrected by the air pressure upstream of the mixer, a pressure sensor is provided in the gas pressure regulator. By providing the load sensor K of the gas engine and determining the value of the pressure sensor when the load is equal to or higher than the specified load, the load is reduced to avoid the air-fuel ratio abnormality due to the abnormality in the supply gas pressure. It is possible to prevent the air-fuel ratio from becoming rich due to breakage of the diaphragm D and abnormal combustion due to the enrichment. Further, it is possible to prevent enrichment of the air-fuel ratio and abnormal combustion due to breakage of the balance line 1.

According to the second aspect of the present invention, in the gas engine configured such that the mixer is provided before the supercharger and the gas pressure supplied to the mixer is corrected by the air pressure upstream of the mixer, A flow switch F is provided at the air pressure outlet, and a load sensor K for the gas engine is provided. By determining whether or not the flow switch F is operating at a specified output or higher, it is caused by an abnormality in the supply gas pressure. Since the load is reduced to avoid the air-fuel ratio abnormality, it is possible to prevent the air-fuel ratio from becoming rich due to the damage of the diaphragm D and the abnormal combustion caused thereby. Further, it is possible to prevent enrichment of the air-fuel ratio and abnormal combustion due to breakage of the balance line 1.

According to a third aspect of the present invention, a supercharger is provided in each bank, a mixer is provided in front of the supercharger, and the gas whose pressure is regulated by one gas regulator is branched and supplied to the mixer. In the V-type supercharged gas engine, the air pressure is taken out from the upstream side of each mixer, merged immediately before the gas regulator, communicated with the gas regulator air chamber, and the flow switch F is connected to the air pressure outlet of each mixer. By providing the load sensor K of the gas engine and determining whether or not the flow switches FL and FR of both banks are operating at the same time under the specified pressure abnormality, the air-fuel ratio abnormality caused by the abnormality of the supply gas pressure is detected. Since the load is reduced to avoid the above, it is possible to prevent the air-fuel ratio from becoming rich due to the damage of the diaphragm D and the abnormal combustion due to the enrichment. Further, it is possible to prevent enrichment of the air-fuel ratio and abnormal combustion due to breakage of the balance line 1.

According to a fourth aspect, each bank is provided with a supercharger, a mixer is provided in front of the supercharger, and the gas regulated by one gas regulator is branched and supplied to the mixer. In the V-type supercharged gas engine, the air pressure is taken out from the upstream side of each mixer, merged immediately before the gas regulator, and the gas pressure is corrected by the average value of the air pressure upstream of the mixer. A constant air-fuel ratio characteristic can be obtained regardless of the increase in pressure loss. Further, even if the pressure loss varies among the air filters between the banks, the average air-fuel ratio can be kept constant, so that abnormal combustion does not occur.

[Brief description of drawings]

FIG. 1 is a drawing showing a fuel supply system and a control circuit in a gas engine.

FIG. 2 is a diagram showing a flowchart of a control circuit of the present invention.

FIG. 3 is a diagram showing a relationship between an air-fuel ratio and a mixer differential pressure with respect to an intake filter pressure loss in the gas engine safety device of the present invention.

FIG. 4 is a diagram showing changes in gas regulator air chamber pressure and fuel air-fuel ratio with respect to engine output in the safety device for a gas engine of the present invention.

FIG. 5 is a drawing showing a fuel supply system and a control circuit of a safety device for a gas engine in which a flow switch F is provided at an air pressure outlet upstream of a mixer.

6 is a drawing showing a flowchart of the safety device for a gas engine of FIG. 5. FIG.

FIG. 7 is a drawing showing a fuel supply system and a control system of a safety device for a gas engine attached to a V-type supercharged gas engine that branches and supplies gas regulated by one gas regulator.

8 is a drawing showing a flowchart of the control device in FIG. 7. FIG.

[Fig. 9] Similarly, in a V-type supercharged gas engine in which gas regulated by one gas regulator is branched and supplied, air pressure is taken out from the upstream of each mixer and merged immediately before the gas regulator. The drawing which shows the fuel supply system and control system of the safety device of the gas engine which correct | amends pressure with the average value of the air pressure of the mixer upstream.

FIG. 10 is a drawing showing changes in mixer inlet air pressure, mixer differential pressure, and air-fuel ratio with respect to elapsed time in the control of FIG. 9.

[Explanation of symbols]

 1 Balance line D Diaphragm F Flow switch S Pressure sensor K Load sensor V Variable valve R Gas regulator

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Claims (4)

[Claims] 1. A gas engine comprising a mixer before the supercharger, wherein the gas pressure supplied to the mixer is corrected by the air pressure upstream of the mixer. By providing a load sensor K of the gas engine and determining the value of the pressure sensor when the load is equal to or higher than the specified load, it is possible to reduce the load to avoid an air-fuel ratio abnormality caused by an abnormality in the supply gas pressure. The safety device of the characteristic gas engine. 2. A gas engine, wherein a mixer is provided in front of the supercharger and the gas pressure supplied to the mixer is corrected by the air pressure upstream of the mixer, and the air pressure outlet upstream of the mixer. Is equipped with a flow switch F and a gas engine load sensor K, and by determining whether or not the flow switch F is operating at a specified output or higher, an air-fuel ratio abnormality due to an abnormality in the supply gas pressure is detected. A gas engine safety device characterized by reducing the load to avoid it. 3. A V-type supercharger is provided in each bank, a mixer is provided in front of the supercharger, and a gas regulated by one gas regulator is branched and supplied to the mixer. In the gas supply engine, the air pressure is taken out from the upstream of each mixer, merged immediately before the gas regulator, and communicated with the gas regulator air chamber, and a flow switch F is provided at the air pressure outlet of each mixer, The load sensor K of the engine is installed so that the flow switches FL of both banks can be used in case of specified pressure abnormality.
A safety device for a gas engine characterized by reducing the load in order to avoid an air-fuel ratio abnormality caused by an abnormality in the supply gas pressure by determining whether the FRs are operating at the same time. 4. A V-type supercharger is provided in each bank, a mixer is provided in front of the supercharger, and a gas regulated by one gas regulator is branched and supplied to the mixer. In the gas supply engine, the air pressure is taken out from the upstream of each mixer, merged just before the gas regulator, and the gas pressure is corrected by the average value of the air pressure in the upstream of the mixer. .