JP2008169706A - Subsidiary chamber type engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a subsidiary chamber type injection engine capable of preventing the large deterioration in engine performance, even when operating under an operation condition of the engine for realizing high efficiency, by stably and accurately supplying fuel gas to an auxiliary chamber. <P>SOLUTION: This subsidiary chamber type engine 100 has a main chamber 1 facing a piston 2, and the auxiliary chamber 17 communicating with the main chamber 1 via a nozzle port 18, as a combustion chamber, and has an auxiliary chamber fuel supply valve 15 supplying the fuel gas G supplied to a valve chest 13 to the auxiliary chamber 17 via a valve part 14, and has a leak passage 31 leaking the fuel gas G from the valve chest of the auxiliary chamber fuel supply valve 15. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention includes, as a combustion chamber, a main chamber facing the piston and a sub chamber communicating with the main chamber via an injection hole.
The present invention relates to a sub-chamber engine provided with a sub-chamber fuel supply valve that supplies fuel gas supplied to a valve chamber to the sub-chamber through a valve portion.

In the sub-chamber engine as described above, in the sub-chamber, fresh air such as a lean air-fuel mixture compressed in the main chamber flows from the nozzle hole, and the fuel gas supplied to the valve chamber of the sub-chamber fuel supply valve Supplied through a valve portion that is opened and closed every cycle, the mixture of the fresh air and the fuel gas is ignited by a spark plug and burned, and a flame jet is injected into the main chamber through the nozzle hole. (For example, refer to Patent Documents 1 and 2).
Further, such a sub-chamber engine can achieve high efficiency because lean combustion in which fuel is burned in a state where the fuel is lean relative to air in the entire combustion chamber can be realized as compared with a single-chamber engine. In particular, it has been introduced into cogeneration systems and the like that require improved efficiency.

JP 2003-317897 A JP 2002-138842 A

In a conventional sub-chamber engine, the amount of fuel supplied from the sub-chamber fuel supply valve to the sub-chamber is likely to fluctuate because the state of the sub-chamber varies due to changes in environmental conditions and operating conditions. In particular, when fuel gas, which is a gas, is used as fuel, fuel gas pulsation occurs in the fuel gas supply path leading to the sub chamber fuel supply valve that repeatedly opens and closes. The amount will be more variable.
Such fluctuations in the amount of fuel gas supplied to the sub chamber cause deterioration in engine performance, such as occurrence of abnormal combustion such as knocking or misfiring, or increase in the exhaust amount of NOx, unburned components, or the like. In particular, under the operating conditions of the engine for realizing high efficiency, the influence of the fluctuation of the fuel gas supply amount to the sub chamber on the engine performance is large.
Therefore, in the conventional sub-chamber engine, in order to prevent the engine performance from greatly deteriorating, at the sacrifice of high efficiency, the operating performance is less affected by the fluctuation of the fuel gas supply amount to the sub-chamber on the engine performance. It was operating and the engine performance could not be improved sufficiently.

  The present invention has been made in view of the above problems, and its purpose is to stably and accurately supply fuel gas to the sub chamber under engine operating conditions for realizing high efficiency. The object is to provide a sub-chamber engine that can prevent a significant deterioration in engine performance even if it is operated.

A sub-chamber engine according to the present invention for achieving the above object includes, as a combustion chamber, a main chamber facing a piston, and a sub-chamber communicating with the main chamber via a nozzle hole,
A sub-chamber engine provided with a sub-chamber fuel supply valve for supplying fuel gas supplied to the valve chamber to the sub-chamber through a valve portion, the first feature of which is a valve of the sub-chamber fuel supply valve A leak path for leaking fuel gas from the chamber is provided.

According to the first characteristic configuration, the fuel gas supplied to the valve chamber of the sub-chamber fuel supply valve leaks into the leak path, thereby opening and closing the valve portion between the valve chamber and the sub-chamber. Regardless, the fuel gas always flows in the valve chamber, and the occurrence of pulsation is suppressed. Therefore, when the valve portion is changed from the closed state to the open state, the fuel gas can be stably and accurately supplied to the sub chamber from the valve chamber in which the pulsation is suppressed.
Therefore, according to the present invention, it is possible to stably and accurately supply the fuel gas to the sub chamber and prevent the engine performance from being significantly deteriorated even when the engine is operated under the engine operating conditions for realizing high efficiency. A room-type engine can be realized.

  According to a second characteristic configuration of the sub-chamber engine according to the present invention, in addition to the first characteristic configuration, the leak path supplies fuel gas leaked from the valve chamber to a fuel supply path or an intake path. It is in a connected point.

  According to the second characteristic configuration, since the fuel gas leaked into the leak path is supplied to the fuel supply path or the intake path through which the fuel gas supplied to the combustion chamber flows, the fuel gas leaks to the leak path. This can prevent an unnecessary increase in fuel consumption.

The third feature configuration of the sub-chamber engine according to the present invention is capable of adjusting the leak amount of the fuel gas from the valve chamber in the leak path in addition to any of the first to second feature configurations. Equipped with a simple leak adjustment valve,
A leak amount control means for controlling the leak amount of the fuel gas by operating the leak amount adjusting valve based on the operating state is provided.

When the fuel gas leaks from the valve chamber of the sub chamber fuel supply valve to the leak path, the amount of fuel gas supplied from the valve chamber to the sub chamber can be changed by changing the leak amount.
Therefore, according to the third feature configuration, the fuel gas supply to the sub chamber is performed by controlling the leak amount of the fuel gas based on the operation state by operating the leak amount adjusting valve provided in the leak path. The amount can be kept appropriate for the driving conditions.

  According to a fourth feature configuration of the sub-chamber engine according to the present invention, in addition to the third feature configuration, the leak amount control means reduces the fuel gas leak amount during start-up operation than during steady operation. Thus, the amount of leakage is controlled.

According to the fourth feature configuration, when controlling the amount of fuel gas leak from the valve chamber to the leak path based on the operating state, by reducing the amount of fuel gas leak during start-up operation than during steady operation, The amount of fuel gas supplied to the sub chamber during the start-up operation can be increased as compared with that during the steady operation. Therefore, at the time of start-up operation that is not sufficiently warmed up, a sufficient concentration of fuel gas can be supplied to the sub chamber to form a relatively high concentration air-fuel mixture. A high-concentration air-fuel mixture can be combusted stably without misfire, and warm-up can proceed smoothly. In a steady operation in which the engine is sufficiently warmed up, the amount of fuel gas supplied to the sub chamber can be reduced as much as possible to achieve high efficiency.
Therefore, after performing the start-up operation in a state where the discharge amount of the unburned components is small and stable, it is possible to shift to a high-efficiency steady operation.

  According to a fifth feature configuration of the sub-chamber engine according to the present invention, in addition to any of the third to fourth feature configurations, the leak amount control means is configured to cause the fuel gas leak amount during cold operation. This is because the amount of leakage is controlled in such a manner that the amount of leakage is reduced as compared with that during warm operation.

According to the fifth characteristic configuration, when the amount of fuel gas leak from the valve chamber to the leak path is controlled based on the operating state, the amount of fuel gas leak during cold operation is reduced than during warm operation. Thus, the amount of fuel gas supplied to the sub chamber during the cold operation can be increased as compared with the warm operation. Therefore, at the time of cold operation that is not sufficiently warmed up, a sufficient amount of fuel gas can be supplied to the sub chamber to form a relatively high concentration mixture, so even in the sub chamber at a relatively low temperature, The high-concentration air-fuel mixture can be combusted stably without misfiring, and warm-up can proceed smoothly. During warm operation that is sufficiently warmed up, the amount of fuel gas supplied to the sub chamber can be reduced as much as possible to achieve high efficiency.
Therefore, at the time of cold operation, it is possible to shift to high-efficiency warm operation after the warm-up is advanced in a state where the discharge amount of unburned components is stable and small.
In the determination of the cold operation and the warm operation, when the temperature of the cooling water, engine oil, cylinder block, etc. is lower than the set temperature, it is determined as the cold operation, and the temperature is the set temperature. The above time can be determined in such a manner that the warm operation is determined.

  According to a sixth feature of the sub-chamber engine according to the present invention, in addition to any of the third to fifth features described above, the leak amount control means may cause the leak amount of the fuel gas during high load operation. This is because the amount of leakage is controlled in such a manner that the amount of leakage is increased more than during low-load operation.

According to the sixth feature, when the amount of fuel gas leaked from the valve chamber to the leak path is controlled based on the operating state, the valve is not operated during high load operation in which the amount of fuel gas supplied to the sub chamber is increased. By increasing the amount of leakage of fuel gas from the chamber from that during low load operation, pulsations that are likely to occur due to an increase in the amount of fuel gas supplied in the valve chamber can be appropriately suppressed.
Therefore, during high-load operation, the amount of leak is increased, and fuel gas is stably and accurately supplied from the valve chamber in which pulsation is appropriately suppressed to the sub chamber. Deterioration can be prevented. On the other hand, during low-load operation where the amount of fuel gas supplied to the sub chamber is reduced due to a decrease in the fuel gas supply pressure, etc., pulsation hardly occurs in the valve chamber, and even if the amount of leakage is reduced, it is relatively stable. And fuel gas can be correctly supplied to a subchamber, and also the power consumption for supplying fuel gas can be suppressed. Therefore, the fuel gas can be stably and accurately supplied to the sub chamber regardless of the engine load.

  According to a seventh characteristic configuration of the sub-chamber engine according to the present invention, in addition to any of the third to sixth characteristic configurations, a plurality of the leak amount adjusting valves are arranged in parallel in the leak path. In the point.

  According to the seventh characteristic configuration, the plurality of leak amount control valves are arranged in parallel in the leak path, and the plurality of leak amount adjusting valves are operated based on the operating state, so that the fuel gas from the valve chamber to the leak path By controlling the amount of leakage, the operating range of one leakage amount adjusting valve can be reduced. Therefore, even if an inexpensive adjustment valve that is relatively small and does not have a high adjustment accuracy is used as the leak amount adjustment valve, the leak amount can be adjusted accurately.

An embodiment of a sub-chamber engine according to the present invention will be described with reference to the drawings.
A sub-chamber engine 100 shown in FIG. 1 includes a piston 2 and a cylinder 3 that houses the piston 2 and forms a main chamber 1 together with the top surface of the piston 2, and reciprocates the piston 2 in the cylinder 3. The intake valve 6 and the exhaust valve 7 are opened and closed to perform intake, compression, combustion / expansion, and exhaust strokes in the main chamber 1, and the piston 2 is reciprocated by a connecting rod (not shown). (This is not shown in the figure) and is output as a rotary motion. Such a configuration is not different from a normal four-stroke internal combustion engine.
The sub-chamber engine 100 is normally configured to be rated so that the engine speed is a constant rated speed.

  The subchamber engine 100 uses city gas (13A), which is a gaseous fuel, as the fuel gas G. The intake valve 6 is opened in the intake stroke, and air is supplied from the intake port 5 to the main chamber 1. A mixture of a small amount of the fuel gas G, preferably a lean mixture, is sucked in the fresh air I, and the intake valve 6 and the exhaust valve 7 are closed in the compression, combustion and expansion strokes, and the sucked fresh air I is compressed. Then, the fuel gas G is combusted and expanded, and the exhaust valve 7 is opened in the exhaust stroke so that the exhaust gas E is discharged from the main chamber 1 to the exhaust port 8.

In addition, in the intake passage 4 leading to the upstream side of the intake port 5, the fuel gas G supplied from the fuel supply passage 25 is mixed with the air A taken into the intake passage 4, and the lean mixture as the fresh air I is mixed. A mixer 28 is formed to form a gas. The mixer 28 has a venturi structure in which the diameter of the intake passage 4 is reduced, and the air A flowing through the intake passage 4 generates a pressure drop by passing through the venturi structure at a high speed, and uses this pressure drop. Thus, the fuel gas G supplied from the fuel supply passage 25 is supplied to the air A flowing through the intake passage 4 to form a lean air-fuel mixture in the intake passage 4.
Further, the fuel supply path 25 is provided with an adjustment valve 26 that can adjust the amount of fuel supplied to the mixer 28 and a governor 27 that maintains the fuel supply pressure to the mixer 28 constant.

The intake passage 4 is provided with a supercharger 29 that supercharges fresh air I. This supercharger 29 is driven by the kinetic energy of the exhaust gas E that flows through the exhaust passage 9 that leads to the downstream side of the exhaust port 8. A turbo that rotates the turbine and supercharges the compressor provided in the intake passage 4 by the rotational force of the turbine, and supercharges the fresh air I flowing through the intake passage 4 by the rotational drive of the compressor. It is configured as a charger.
In this embodiment, a turbocharger is provided as the supercharger 29. Instead of this turbocharger, another type of supercharger such as a supercharger that rotates the compressor using the rotational force of the crankshaft 4 is used. A machine may be provided.

  A so-called deep dish-shaped recess 2 a is formed at the center of the top surface of the piston 2. By forming the concave portion 2a as described above, squish flowing from the outer peripheral portion of the top surface of the piston 2 to the central portion of the concave portion 2a is generated when the piston 2 rises in the compression stroke.

  The cylinder head 30 of the sub-chamber engine 100 is provided as a combustion chamber together with the main chamber 1, and is provided with a sub-chamber 17 communicating with the main chamber 1 through the injection hole 18. The structure of the chamber mechanism 10 will be described below.

Above the sub chamber 17, an ignition plug 19 and a sub chamber fuel supply valve 15 are provided.
The spark plug 19 is configured to spark-ignite the air-fuel mixture formed in the sub chamber 17 by generating a spark every cycle.

On the other hand, the sub-chamber fuel supply valve 15 opens and closes the valve portion 14 for each cycle, so that the fuel gas G supplied from the sub-chamber fuel supply passage 22 to the valve chamber 13 passes through the valve portion 14 to the sub chamber 17. It is comprised so that it may supply intermittently.
The sub-chamber fuel supply path 22 has a supply pump 20 for increasing the supply pressure of the fuel gas G to the valve chamber 13 to about 0.2 MPa (Gauge), and the fuel gas supply amount to the valve chamber 13 can be adjusted. A control valve 21 is provided.

Hereinafter, the operation state of one cycle in the sub-chamber engine 100 will be described below.
In the sub-chamber engine 100, first, the intake valve 6 is opened, and the intake stroke in which the fresh air I is drawn from the intake port 5 into the main chamber 1 is performed by the lowering of the piston 2 from TDC (top dead center). Is called.
At this time, the sub chamber fuel supply valve 15 installed in the sub chamber 17 changes the valve portion 14 from the closed state to the open state at a time slightly delayed from the opening timing of the intake valve 6, and supplies the valve chamber 13 to the valve chamber 13. The supply of the fuel gas G to the sub chamber 17 is started.

Later, the intake valve 6 and the valve portion 14 of the sub-chamber fuel supply valve 15 are closed at substantially the same time, and a so-called compression stroke is performed in which the fresh air I sucked into the main chamber 1 is compressed by the rise of the piston 2. Is called.
In addition, when the sub chamber 17 in the initial stage of the compression stroke is still in a low pressure state, the valve portion 14 of the sub chamber fuel supply valve 15 may be opened to supply the fuel gas G to the sub chamber 17.

In this compression stroke, as the piston 2 moves up, the volume of the main chamber 1 decreases, and the fresh air I in the main chamber 1 flows into the sub chamber 17 through the nozzle holes 18. When the gas flows due to the inflow, the fresh air I and the fuel gas G are mixed, and an air-fuel mixture having an equivalent ratio within the spark ignition possible range (for example, about 1) is formed.
That is, at the end of the compression stroke, the sub-chamber 17 has a mixture with a relatively high equivalence ratio, whereas the main chamber 1 has fresh air I with a relatively low equivalence ratio. become.

Next, the sub-chamber engine 100 operates the spark plug 19 immediately before top dead center, for example, near 8 ° BTDC, and sparks and burns in the upper portion of the sub-chamber 17.
Then, the combustion proceeds in the sub chamber 17, and the flame jet F is jetted into the main chamber 1 through the nozzle hole 18 together with the fuel gas G not burned in the sub chamber 17.
Further, a plurality of nozzle holes 18 communicating with the sub chamber 17 and the main chamber 1 are distributed at equal intervals in the circumferential direction around the central axis X of the main chamber 1 and extend radially. The flame jets F are configured to be ejected radially from the respective nozzle holes 18 into the main chamber 1.

On the other hand, in the main chamber 1, since the lean air-fuel mixture sucked as the fresh air I is stably burned by the flame jets F ejected radially from the respective nozzle holes 18, the high pressure is not accompanied by a rapid pressure increase. Combustion that is efficient and results in low NOx.
Although the combustion state in the main chamber 1 is a state close to that of a normal SI engine, knocking does not occur even when the compression ratio is set high, so that the thermal efficiency can be improved. Further, even when the equivalence ratio of the fresh air I sucked into the main chamber 1 is increased and the output is increased, knocking can be avoided well, so that the equivalence ratio at the knocking limit can be increased. A wide output adjustment range is ensured.

In the sub-chamber engine 100 described above, in order to minimize the thermal energy of the flame jet F and suppress abnormal combustion such as knocking in the main chamber 1 during high-load operation, the main chamber 1 and the sub-chamber 17 are The volume ratio of the sub chamber 17 is several percent (for example, about 2% to 3%) with respect to the minimum volume of the combustion chamber that is included, that is, the volume of the combustion chamber that is minimum when the position of the piston 2 is the top dead center position. ) And designed to be very small.
In FIG. 1, in order to make it easy to recognize the internal structure of the sub chamber mechanism 10, the ratio of the size of the sub chamber mechanism 10 to the whole is drawn larger.

The above is the description of the basic configuration of the sub-chamber engine 100. The characteristic configuration of the sub-chamber engine 100 will be described below.
The sub chamber type engine 100 suppresses the occurrence of pulsation in the valve chamber 13 of the sub chamber fuel supply valve 15 and supplies the fuel gas G to the sub chamber 17 stably and accurately. A leak path 31 for leaking the fuel gas G is provided. Although details will be described later, since the leak amount adjustment valve 32 provided in the leak path 31 is normally open, the fuel gas G supplied to the main chamber 13 can flow to the leak path 31 side.
That is, in the valve chamber 13, the fuel gas G always flows regardless of the opening / closing operation of the valve portion 14 of the sub-chamber fuel supply valve 15, and further, the fuel gas G flowing into the leak path 31 is Since it is supplied to the intake passage 4 through a leak amount adjusting valve 32 described later, the occurrence of pulsation due to the opening / closing operation of the valve portion 14 is suppressed. Therefore, when the valve portion 14 is changed from the closed state to the open state and the supply of the fuel gas G to the sub chamber 17 is started, the fuel is stably and accurately transferred from the valve chamber 13 in which the pulsation is suppressed to the sub chamber 17. Gas G is supplied.

Further, the end of the leak path 31 opposite to the valve chamber 13 is connected to the upstream side of the supercharger 29 that has a relatively low pressure, preferably a negative pressure, in the intake path 4. Therefore, the fuel gas G leaked into the leak path 31 due to the differential pressure between the supply pressure of the supply pump 20 and the upstream pressure of the supercharger 29 in the intake path 4 is supplied to the main chamber 13 as follows: The air is satisfactorily supplied to the intake passage 4 and is sucked into the main chamber 1 together with the fresh air I and used for combustion.
In the present embodiment, the leak path 31 is connected to the upstream side of the supercharger 29 in the intake path 4. However, the leak path 31 is separated from the inlet side of the supply pump 20 in the fuel supply path 22. The fuel gas G leaking into the leak path 31 may be used for combustion.

  Further, in the sub-chamber engine 100, in addition to the leak path 31, the fuel gas G that is about to leak to the outside through the guide portion 12 of the sub-chamber fuel supply valve 15 is also taken in like the leak path. A recovery path 35 for supplying to the path 4 side is provided. The amount of the fuel gas G leaking to the recovery path 35 side is compared with the amount of the fuel gas G leaking to the leak path 31 side. Very few.

The leak path 31 is provided with a leak amount adjustment valve 32 capable of adjusting the leak amount of the fuel gas G from the valve chamber 13, and further operates the leak amount adjustment valve 32 on the basis of the operating state so as to operate the fuel gas. A leakage amount control means 33 for controlling the leakage amount of G is provided in a form in which an ECU (not shown) composed of a computer functions.
Further, a plurality of, specifically, two leak amount adjusting valves 32 are arranged in parallel in the leak path 31, and the opening degree of all the leak amount adjusting valves 32 is adjusted at the same time. The amount of leaked fuel gas G is adjusted.
Therefore, even if the adjustment range and the adjustment accuracy of each leak amount adjusting valve 32 are relatively small, the leak amount can be adjusted relatively greatly and accurately.

As described above, the sub-chamber engine 100 is provided with the leak amount adjusting valve 32 and the leak amount control means 33, so that the supply amount of the fuel gas G to the sub chamber 17 is kept appropriate for the operating state. can do.
Next, a description will be given of start-up control, warm-up state control, and load state control as specific leak amount control methods by the leak amount control means 33.

(Startup control)
The leak amount control means 33 is configured to execute start-up control for controlling the leak amount in a form in which the leak amount of the fuel gas G is reduced during start-up operation than during steady operation.
That is, in the activation control, the leak amount control means 33 measures the elapsed operation time from the operation start time as activation information, and determines that the elapsed operation time is less than a preset time as the activation operation. The time when the operation elapsed time is equal to or longer than the set time is determined as the steady operation time.
The leak amount control means 33 reduces the opening of the leak amount adjustment valve 32 during the start-up operation as compared with during the steady operation, and leaks the fuel gas G from the valve chamber 13 to the leak path 31. Since the amount is reduced, as a result, the supply amount of the fuel gas G from the valve chamber 13 to the sub chamber 17 at the start-up operation increases compared to the steady operation.
Accordingly, during the start-up operation, a relatively high concentration air-fuel mixture is formed in the sub chamber 17, and the high concentration air-fuel mixture burns stably without misfiring, so that warm-up proceeds smoothly and becomes steady early. You can move on to driving.
On the other hand, during the steady operation when the operation elapsed time has reached the set time, the sub chamber 17 is sufficiently warmed up, so that the leakage amount is increased and the fuel gas G to the sub chamber 17 is increased. By reducing the supply amount as much as possible, a stable combustion state of the air-fuel mixture can be maintained in the sub chamber 17 even if high efficiency is achieved.

(Warm-up state control)
The leak amount control means 33 is configured to execute warm-up state control for controlling the leak amount in a form in which the leak amount of the fuel gas G is reduced during the cold operation as compared with that during the warm operation.
That is, in the warm air state control, the leak amount control means 33 measures the temperature of the cooling water, engine oil, cylinder block, outside air, etc. as the warm-up state information, and keeps the cold state while the temperature is lower than the set temperature. It is determined as the time of operation, and the time during which the temperature is higher than the set temperature is determined as the time of the warm operation.
The leak amount control means 33 reduces the opening degree of the leak amount adjustment valve 32 during the cold operation compared to during the warm operation, so that the fuel gas G from the valve chamber 13 to the leak path 31 is reduced. As a result, the supply amount of the fuel gas G from the valve chamber 13 to the sub chamber 17 during the cold operation is increased as compared with that during the warm operation.
Accordingly, during the cold operation, a relatively high concentration mixture is formed in the sub chamber 17, and the high concentration mixture is stably burned without misfiring, so that warm-up proceeds smoothly and early. It is possible to shift to warm operation.
On the other hand, during the warm operation when the temperature as the warm air state information has reached the set temperature, the sub chamber 17 is sufficiently warmed up, so the leak amount is increased and the sub chamber 17 is moved to. By reducing the supply amount of the fuel gas G as much as possible, a stable combustion state of the air-fuel mixture can be maintained in the sub chamber 17 even if the efficiency is improved.

(Load status control)
The sub-chamber engine 100 performs so-called load control that controls the supply amount of the fuel gas G to the sub-chamber fuel supply valve 15 and the mixer 28 by operating the regulating valve 21 and the regulating valve 26 based on the engine load. To do.
That is, in the load control, as the engine load increases, the opening degree of the regulating valve 21 and the regulating valve 26 is increased, and the supply amount of the fuel gas G to the sub chamber fuel supply valve 15 and the mixer 28 is increased. The output suitable for the engine load can be taken out. However, in such load control, as the engine load increases, the amount of fuel gas G supplied to the sub chamber 17 increases, so that pulsation is likely to occur in the valve chamber 13 of the sub chamber fuel supply valve 15. .
Therefore, when performing the load control as described above, the leak amount control means 33 executes load state control for controlling the leak amount in a form in which the leak amount of the fuel gas G is increased during the high load operation than during the low load operation. Is configured to do.
That is, in the load state control, the leak amount control means 33 measures load state information for obtaining the engine load such as the engine speed and torque, and the engine load obtained from the load state information is a preset set load. During this time, it is determined that the engine is operating at a high load, and when the engine load is less than the set time, it is determined that the engine is operating at a low load.
The leak amount control means 33 expands the opening of the leak amount adjustment valve 32 during the high load operation as compared to during the low load operation, so that the fuel gas G from the valve chamber 13 to the leak path 31 is increased. As a result, the pulsation in the valve chamber 13 of the sub chamber fuel supply valve 15 is appropriately suppressed.
Accordingly, during high load operation in which the supply amount of the fuel gas G to the sub chamber 17 is increased, the fuel gas G is stably and accurately supplied to the sub chamber 17 from the valve chamber 13 in which the pulsation is appropriately suppressed. A significant deterioration in engine performance due to fluctuations in the supply amount of G is prevented.
On the other hand, at the time of low load operation in which the supply amount of the fuel gas G to the sub chamber 17 is reduced, since the pulsation hardly occurs in the valve chamber 13, the leak amount of the fuel gas G to the leak path 31 is reduced. While the waste of power by the supply pump 20 for supplying the fuel gas G is suppressed, the fuel gas G is supplied from the valve chamber 13 to the sub chamber 17 stably and accurately.

[Another embodiment]
(1) In the above embodiment, the leakage amount control means 33 changes the operating state such as the startup time information, the warm-up permanent information, the load state information, etc., as in the start-up control, the warm-up state control, and the load state control. On the basis of this, the leak amount adjusting valve 32 is operated to start the control of the leak amount of the fuel gas G in the valve chamber 13 to the leak path 32. However, the configuration for executing these controls as appropriate is provided. It can be omitted.

(2) As described in the above embodiment, the sub-chamber engine according to the present invention exhibits an excellent effect when a gaseous fuel gas such as city gas is used. Such a fuel gas In addition to the city gas, there are gaseous fuels other than hydrocarbons mainly composed of CO and H ₂ such as hydrogen and propane.

  The sub-chamber engine according to the present invention significantly deteriorates the engine performance even if the engine is operated under the operating condition of the engine for realizing high efficiency by stably and accurately supplying the fuel gas to the sub-chamber. It can be effectively used as a sub-chamber engine that can prevent the above.

Partial sectional view of sub-chamber engine

Explanation of symbols

1: Main chamber 4: Intake passage 9: Exhaust passage 13: Valve chamber 14: Valve portion 15: Sub chamber fuel supply valve 17: Sub chamber 18: Injection hole 22: Sub chamber fuel supply passage 31: Leak passage 32: Leakage amount Regulating valve 33: Leak amount control means 100: Sub-chamber engine A: Air E: Exhaust gas F: Flame jet G: Fuel gas I: Fresh air

Claims (7)

The combustion chamber includes a main chamber facing the piston, and a sub chamber communicating with the main chamber via an injection hole.
A sub-chamber engine provided with a sub-chamber fuel supply valve for supplying fuel gas supplied to the valve chamber to the sub-chamber through a valve portion;
A sub-chamber engine having a leak path for leaking fuel gas from the valve chamber of the sub-chamber fuel supply valve.   2. The sub-chamber engine according to claim 1, wherein the leak path is connected so as to supply fuel gas leaked from the valve chamber to a fuel supply path or an intake path. The leak path includes a leak amount adjusting valve capable of adjusting the leak amount of the fuel gas from the valve chamber,
3. The sub-chamber engine according to claim 1, further comprising a leak amount control unit that controls the leak amount of the fuel gas by operating the leak amount adjusting valve based on an operating state.   The sub-chamber engine according to claim 3, wherein the leak amount control means controls the leak amount in a form in which the leak amount of the fuel gas is reduced during start-up operation than during steady operation.   5. The sub-chamber engine according to claim 3, wherein the leak amount control unit controls the leak amount in a form in which the leak amount of the fuel gas is reduced during a cold operation than during a warm operation.   The sub-chamber according to any one of claims 3 to 5, wherein the leak amount control unit controls the leak amount in a form in which the leak amount of the fuel gas is increased during high load operation than during low load operation. Expression engine.   The sub-chamber engine according to any one of claims 3 to 6, wherein a plurality of the leak amount adjusting valves are arranged in parallel in the leak path.

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