JP4007729B2 - Engine and operation method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine that burns fuel and oxygen-containing gas in a main chamber, reciprocates a piston in a cylinder, and maintains the rotation of a crankshaft, and an operating method thereof.
[0002]
[Prior art]
Engines that are internal combustion engines are broadly divided into spark ignition engines (SI engines) and diesel engines.
The SI engine sucks air (an example of combustion oxygen-containing gas) and fuel into the combustion chamber (main chamber), compresses it, and forcibly ignites with a spark plug. The ideal cycle of this SI engine is It is considered an Otto cycle (constant volume heating cycle). By increasing the compression ratio and performing lean combustion, the thermal efficiency of the Otto cycle is improved. However, when the compression ratio is increased, knocking occurs in which the end gas self-ignites before the end of combustion by normal flame propagation, and a deviation from the optimum ignition timing at which the torque is truly maximized occurs, resulting in a decrease in thermal efficiency. Therefore, there is a limit to increasing the compression ratio and improving the thermal efficiency. For example, the compression ratio is at most 10 or less, and the thermal efficiency ηe at this time is about 30%.
[0003]
[Problems to be solved by the invention]
As a countermeasure against engine exhaust gas, it has been found that it is sufficient to completely burn with a very thin air-fuel mixture that generates little CO, HC and NOx. In order to improve thermal efficiency, it is effective to burn the thin air-fuel mixture by reducing the pumping loss without reducing the intake air (an example of oxygen-containing gas), but the ignitability and combustion of the air-fuel mixture Instability issues need to be resolved.
In addition, a diesel engine can inject fuel at any time by a fuel injection device that injects fuel at a high pressure. Therefore, unlike a SI engine, knocking due to an increase in flame propagation pressure does not occur. Although it can be set high and efficiency can be improved, it is necessary to inject high pressure fuel into highly compressed intake air (an example of an oxygen-containing gas), which requires a complicated and expensive fuel injection valve. When the fuel is a gaseous fuel such as natural gas, it is very difficult to supply the gaseous fuel to the high-pressure combustion chamber, and the engine of such a gaseous fuel is overwhelmingly an SI engine. It was difficult to improve the efficiency of the engine.
[0004]
Therefore, in view of the above circumstances, the present invention aims to provide a high-efficiency engine with a high compression ratio, and in particular, to provide a high-efficiency engine that can also be applied to a gaseous fuel engine. Objective.
[0005]
[Means for Solving the Problems]
According to the present invention for solving such a problem, a characteristic configuration of an engine that burns fuel and oxygen-containing gas in a main chamber, reciprocates a piston in a cylinder, and maintains rotation of a crankshaft is claimed in claim 1 And a first sub chamber communicating with the main room via a first communication path, and a second sub chamber communicating with the main room via a second communication path,
Flame injection means for igniting by forming an air-fuel mixture in the first sub chamber, and for injecting the flame formed in the first sub chamber into the main chamber via the first communication path;
And a mixture injection means for forming an air-fuel mixture in the second sub chamber and for injecting the air-fuel mixture formed in the second sub chamber into the main chamber via a second communication path.
[0006]
In general, there are four-cycle engines and two-cycle engines, and the operation cycle of the four-cycle engine is operated through an intake stroke, a compression stroke, a combustion / expansion stroke, and an exhaust stroke in accordance with the reciprocating motion of the piston. The two-cycle engine is operated through a scavenging / compression stroke, a combustion / expansion / exhaust stroke, and in both engines, the fuel and oxygen-containing gas are compressed and burned in the main chamber (combustion chamber), and the piston is placed in the cylinder. The engine of the present invention can be applied to 4-cycle and 2-cycle engines.
[0007]
In the engine of the present invention, air (an example of an oxygen-containing gas) is sucked into a main chamber from an intake port or the like in an intake stroke or a scavenging stroke.
Next, in the compression stroke, by compressing the sucked air, the air in the main chamber flows into the first sub chamber and the second sub chamber via the first communication path and the second communication path, and the intake stroke. Alternatively, in the initial stage of the compression stroke or in the scavenging / compression stroke, for example, when the pressure in the main chamber is still in a low pressure state, fuel is supplied to the first sub chamber and the second sub chamber, and the first sub chamber and the second sub chamber An air-fuel mixture is formed in the sub chamber.
Next, in the combustion stroke, the air-fuel mixture in the first sub-chamber is ignited by the flame ejection means, and a flame torch is ejected into the main chamber via the first communication path, and the air-fuel mixture in the second sub-chamber is The air-fuel mixture formed in the second sub-chamber is ejected into the main chamber via the second communication path by the air-fuel mixture ejecting means that extrudes to the chamber side.
[0008]
By configuring in this way, in the main chamber, the jetted air-fuel mixture is gradually ignited by the jetted flame and burned completely, so that a combustion mode close to a so-called diesel cycle is realized. Even if the ratio φ is greatly changed to 0.2 to 1.0, complete combustion can be performed in a preferable state. Therefore, for example, even when the equivalence ratio φ of the air-fuel mixture is set to be extremely lean, such as about 0.35, the fuel can be completely burned in a preferable state, so that the specific heat ratio is high and the efficiency is high. The emission of fuel components can be reduced, and the occurrence of knocking can be prevented, so that the compression ratio can be set high and the engine efficiency can be further improved.
In addition, the compression ratio of a normal diesel engine is determined by the characteristics of the fuel. However, in the engine of the present invention, the air-fuel mixture is forcibly ignited by a spark plug or the like, so the compression ratio can be freely set to about 6 to 20, for example. Therefore, when the fuel is city gas, the compression ratio is set within the range of 17 to 19, and the thermal efficiency ηe is about 41%. Can do.
[0009]
In such an engine, an air-fuel mixture having an equivalence ratio in the combustible range is formed in the first sub chamber during ignition. Complete Preferably, the air-fuel mixture in the first sub chamber can be easily ignited and burned. Further, it is preferable that the equivalence ratio of the air-fuel mixture formed in the second sub-chamber before jetting of the air-fuel mixture is equal to or higher than the upper limit of combustion. it can.
[0010]
Further, in the engine as described above, the claim 2 As described above, the injection direction of the air-fuel mixture in the main chamber by the air-fuel mixture injection means is configured to be directed to the area of the flame injected into the main chamber by the flame injection means. Is preferred.
[0011]
By configuring as described above, the air-fuel mixture ejected into the main chamber can be ignited in a preferable state by the flame ejected into the main chamber, and the generation of unburned components can be further suppressed. Further, combustion in a lean region can be realized.
The flame region injected by the flame injection means indicates a region where the flame jetted from the first communication path into the main chamber exists in the main chamber. For example, the jetted flame runs along the inner wall of the cylinder. In the case of refraction or swirling, it is preferable that the air-fuel mixture is ejected from the second communication path toward the flame region formed in the main chamber, and the flow direction of the first communication path and the second communication path is not necessarily limited Need not be crossed in the main room.
[0012]
In these engines, the claims 3 The first fuel supply means for supplying a part of the fuel to the first sub chamber, and a spark plug for igniting the air-fuel mixture in the first sub chamber,
The flame injection means activates the first fuel supply means, supplies fuel to the first sub chamber, forms an air-fuel mixture with the oxygen-containing gas in the first sub chamber, activates the spark plug, An air-fuel mixture formed in one sub chamber is ignited to form a flame in the first sub chamber, and the flame formed in the first sub chamber is ejected to the main chamber via the first communication path. Can do.
[0013]
By configuring in this way, it is possible to simply configure the flame injection means for injecting flame into the main chamber. By supplying the fuel to the first sub chamber by the first fuel supply means, the fuel can be supplied in a low pressure state, and the first fuel supply means can be configured simply and inexpensively. Further, when using a pre-pressurized gaseous fuel such as city gas as the fuel, the first fuel supply means does not need to pressurize the fuel, so that a reed valve having a simple structure can be used. .
[0014]
In these engines, the claims 4 The second fuel supply means for supplying a part of the fuel to the second sub chamber, and a sub chamber communication path that communicates the first sub chamber and the second sub chamber. ,
The air-fuel mixture injection means operates the second fuel supply means to supply fuel to the second sub chamber to form an air-fuel mixture with the oxygen-containing gas in the second sub chamber, and to form the first sub chamber The pressure wave of the generated flame is propagated to the second sub chamber through the sub chamber communication path, and the air-fuel mixture formed in the second sub chamber is ejected to the main chamber through the second communication path. be able to.
[0015]
By comprising in this way, the air-fuel mixture ejection means which ejects air-fuel mixture to a main chamber can be comprised easily. That is, air flows from the main chamber into the second sub chamber through the second communication path in the compression stroke, and fuel is supplied to the second sub chamber by the second fuel supply means, for example, in the initial stage of the intake stroke, the compression stroke or the scavenging stroke. Is supplied in a low pressure state to form an air-fuel mixture in the second sub chamber. Next, the air-fuel mixture in the first sub chamber is ignited and combusted. The pressure wave generated by the combustion in the first sub chamber is guided to the second sub chamber via the sub chamber communication path, and the pressure wave The air-fuel mixture in the second sub chamber can be ejected from the second communication path to the main chamber in a high pressure state.
Therefore, the second fuel supply means does not need to inject fuel at a high pressure, and can be configured simply and inexpensively. Even in an engine using gaseous fuel, the air-fuel mixture is mainly used at a high pressure. An engine that realizes combustion close to a so-called diesel engine that is ignited by being ejected into a chamber can be configured. Also, when using a pre-pressurized gaseous fuel such as city gas as the fuel, the second fuel supply means does not need to pressurize the fuel, so use a simple structure such as a reed valve. Can do.
[0016]
Further, in such an engine, fuel is supplied to the first sub chamber so that the equivalence ratio of the air-fuel mixture formed in the first sub chamber is within the combustible range, and the equivalence ratio of the air-fuel mixture in the second sub chamber is It is preferable to supply the fuel to the second sub chamber so that the combustion upper limit is exceeded, and the flame does not propagate from the first sub chamber to the second sub chamber via the sub chamber communication path, and the first sub chamber is in a preferable state. The air-fuel mixture can be injected from the two sub chambers into the main chamber.
[0017]
Further, in an engine having such a sub chamber communication path, 5 As described above, the first fuel supply means and the second fuel supply means may include a fuel supply valve for supplying fuel into the sub chamber communication path or to the second sub chamber.
[0018]
That is, when the engine of the present invention has the sub chamber communication path, the fuel supply valve is provided as the first fuel supply means via the sub chamber communication path by providing at least one fuel injection valve as described above. A fuel can be supplied to one sub-chamber and fuel can be supplied to the second sub-chamber directly or via a sub-chamber communication path as a second fuel supply means. Can be configured.
[0019]
In the engine having the sub chamber communication path, ,in front The flow resistance of the first communication path is configured to be smaller than the flow resistance of the second communication path. Is preferable .
[0020]
With this configuration, a large amount of air sucked into the main chamber flows into the first communication path rather than the second communication path in the compression stroke, and the first sub-chamber is near the end of the compression stroke. The amount of air that flows into the air increases more than the air that flows into the second sub chamber. Therefore, even if the same amount of air-fuel mixture is supplied to each sub-chamber, the air-fuel mixture formed in the first sub-chamber is thinner than the air-fuel mixture formed in the second sub-chamber. The equivalent ratio of the air-fuel mixture in the second sub-chamber is equal to or higher than the upper limit of combustion, and a flame is formed in the first sub-chamber in a preferable state and a flame is injected into the main chamber. The pressure wave can be propagated to the second sub chamber through the sub chamber communication path, and the air-fuel mixture in the second sub chamber can be ejected to the main chamber without igniting.
[0021]
Further, in an engine having such a sub-chamber communication path, 1 As described above, a reed valve is provided in the second communication path to block the flow from the main chamber to the second sub chamber.
[0022]
Further, as described above, the reed valve is provided in the second communication path, and the air introduced from the main chamber into the second sub chamber through the second communication path in the compression stroke is prevented, so that the second sub chamber can be connected to the second sub chamber. The inflow of air is reduced, the equivalence ratio of the air-fuel mixture in the second subchamber is more than the upper combustion limit, and the equivalence ratio of the air-fuel mixture in the first subchamber is in a leaner state near the lower combustion limit within the combustible range. For example, even when the amount of fuel to be supplied is increased during high load operation, the equivalent ratio of the air-fuel mixture in the first sub chamber can be set within the combustible range.
[0023]
Furthermore, in an engine having such a sub-chamber communication path, 6 It is also preferable that the flow path resistance of the first communication path is larger than the flow path resistance of the sub chamber communication path.
[0024]
With this configuration, the pressure wave of the flame formed in the first sub chamber is preferentially propagated to the sub chamber communication path side, and the air-fuel mixture formed in the second sub chamber is more connected to the second chamber. The air-fuel mixture can be ejected vigorously into the main chamber by extruding to the road side.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the engine of the present invention will be described with reference to the drawings.
An engine 100 according to the present invention shown in FIG. 1 includes a piston 2 connected to a connecting rod 6 by a piston pin 7 and a cylinder 3 that houses the piston 2 and forms a main chamber 1 together with the piston upper end surface. Is reciprocated in the cylinder 3, and the intake valve 32 and the exhaust valve 33 are opened and closed to take in fresh air into the main chamber 1 and perform various steps of intake, compression, combustion / expansion, and exhaust in the main chamber 1. The reciprocating motion of the piston 2 is output as the rotational motion of the crankshaft 4 by the connecting rod 6, and such a configuration is not different from a normal 4-stroke internal combustion engine.
[0026]
The engine 100 uses city gas (13A) as the fuel G. The intake valve 32 is opened in the intake stroke, and air A is sucked into the main chamber 1 as an oxygen-containing gas. The compressed air A is compressed, and the fuel G is supplied to a fuel supply valve 30 described later and supplied to the engine 100.
[0027]
Further, the cylinder head 9 of the engine 100 is provided with a sub chamber member 50, and the sub chamber member 50 is communicated with the main chamber 1 by three first communication paths 11 as shown in FIGS. 1 and 2. A first sub chamber 10 and a second sub chamber 20 communicated with the main chamber 1 by three second communication paths 21. The first sub chamber 10 and the second sub chamber 20 are connected to a sub chamber communication path 31. The flow resistance of the first communication path 11 is S1, the flow resistance of the second communication path 21 is S2, and the flow resistance of the sub chamber communication path 31 is SS.
SS <S1 <S2
Are related and formed.
In addition, the internal diameter of the flow path of a 1st connection path is 2.5 mm, and the internal diameter of the flow path of a 2nd connection path is 1.0 mm.
[0028]
Further, a fuel supply valve 30 is provided above the second sub chamber 20, and is configured to supply the fuel G to the second sub chamber 20 using the gas pressure of the fuel G stored in a compressed state. ing. A spark plug 8 is provided above the first sub chamber 10 so as to ignite an air-fuel mixture in the first sub chamber described later.
[0029]
Next, the operation state in one cycle of the engine 100 of the present invention will be described with reference to the drawings. The piston position when the volume of the main chamber 1 is minimum is called top dead center (TDC), the piston position when the volume of the main chamber 1 is maximum is called bottom dead center (BDC), and the crank angle is the top in the rotational direction. The angle is expressed as an angle of the dead center with respect to the crankshaft. When the position is before the top dead center, BTCD is appended after the angle value, and when the position is after the top dead center, ATCD is appended after the angle value.
[0030]
First, as shown in FIG. 5, the engine 100 of the present invention opens the intake valve 32 when the crank angle is 22 ° BTDC, the piston descends through the top dead center, and the air A is sucked into the main chamber 1. .
Later, when the crank angle is 110 ° BTDC, the intake valve 32 is closed, the piston 2 rises, and the air A in the main chamber 1 is compressed.
Due to the compression of the air A in the main chamber 1, the compressed air A in the main chamber 1 passes through the first communication path 11 and the second communication path 21 as shown in FIG. The first sub chamber 10 flows into the second sub chamber 20, and the first sub chamber 10 is more than the second sub chamber 20 because of the relationship between the flow passage cross-sectional areas of the respective communication paths 11, 21, that is, the flow passage resistance. Much air A flows in.
[0031]
Further, when the crank angle is 110 ° BTDC, that is, when the intake valve is closed, the fuel supply valve 30 is operated, and when the second sub chamber is still in the low pressure state, the fuel G is used by utilizing the gas pressure of the fuel. Supply to the second sub chamber 20. Most of the supplied fuel G remains in the second sub chamber 20, but a part of the fuel G flows into the first sub chamber 10 through the sub chamber communication path 31, and as a result, compression is completed and before ignition. At this point, an air-fuel mixture of fuel G and air A set to an equivalence ratio within the combustible range is formed in the first sub chamber 10, and the remaining fuel G and air A are formed in the second sub chamber 20. Thus, an air-fuel mixture having an equivalent ratio exceeding the upper limit of combustion can be formed.
[0032]
Next, when the crank angle is 10 ° BTDC, the spark plug 8 is actuated to ignite an air-fuel mixture having an equivalence ratio within the combustible range formed in the first sub chamber 10 and shift to the combustion / expansion stroke. This will be described in detail below.
First, when the spark plug 8 is operated, the equivalence ratio φ of the air-fuel mixture formed in the first sub chamber 10 is in the combustible range of about 0.65 to 1.2. To ignite this mixture. Then, the air-fuel mixture in the first sub chamber 10 easily burns, the internal pressure in the first sub chamber 10 rises, and as shown in FIG. 4, the flame in the first sub chamber 10 flows from the first communication path. The main chamber 1 is ejected and a flame torch F is formed in the main chamber 1. In this way, an air-fuel mixture is formed in the first sub chamber 10 and ignited by the spark plug 8, and the flame formed in the first sub chamber 10 is ejected to the main chamber 1 through the first communication path 11. This means is called flame injection means X.
[0033]
Furthermore, simultaneously with the formation of the flame torch F, the pressure wave propagates in a preferable state to the sub chamber communication path 31 side having a smaller flow path resistance than the first communication path 11 due to an increase in the internal pressure of the first sub chamber 10. Propagates to the second sub chamber 20. Therefore, since the equivalence ratio of the air-fuel mixture formed in the second sub chamber 20 is equal to or higher than the upper limit of combustion, the second communication path is utilized by using the pressure wave from the first sub chamber 10 without ignition. 21 is ejected to the main chamber through the main chamber 1, and an ejected air-fuel mixture M directed to the flame torch F region is formed in the main chamber 1. As described above, the pressure wave generated by the combustion in the first sub chamber 10 is propagated to the second sub chamber 20 through the sub chamber communication path 31, and the air-fuel mixture formed in the second sub chamber 20 is transmitted to the second communication path. The means for jetting into the main chamber 1 through 21 is referred to as the mixture injection means Y.
[0034]
By performing the combustion / expansion stroke as described above, the jet mixture M ejected from the second communication path 21 toward the flame torch F of the main chamber 1 is caused by the flame torch F ejected from the first communication path 11. It is ignited in a preferable state, and the air-fuel mixture M gradually burns in the main chamber 1, pushes down the piston 2, opens the exhaust valve in the exhaust stroke, and exhausts the exhaust gas after combustion.
Such a combustion state becomes a state close to a so-called diesel cycle (constant pressure cycle), and compresses air rather than compressing the air-fuel mixture in the main chamber 1, so that knocking can be suppressed, The compression ratio can be set high and the efficiency can be improved. In addition, the engine can be operated in an ultra-lean state where the equivalent ratio φ of the mixture of fuel G and air A burned in one cycle is about 0.35, and emissions of CO, HC, NOx, etc. can be reduced. it can.
[0035]
Next, in order to confirm the efficiency improvement effect of the engine according to the present invention, the compression ratio was changed from 6 to 20 in the structure of the engine 100 shown in the above embodiment, and the efficiency was measured. Moreover, as a comparative example, the fuel is an engine using city gas, and an SI engine (Comparative Example 1) that inhales an air-fuel mixture and ignites sparks, and a diesel engine that directly sprays fuel into a combustion chamber at a high pressure (Comparative Example). 2) was prepared, and the efficiency was similarly measured by changing the compression ratio.
[0036]
As a result, the engine 100 according to the present invention can operate from a compression ratio of 6 to 20, and when the compression ratio is 6, the efficiency ηe is 27%, which is the lowest value. When the compression ratio is about 17 to 19, the efficiency ηe shows the highest value of about 41%. When the compression ratio is further increased, the efficiency is slightly lowered, and when the compression ratio is 20, the efficiency ηe is It was found to be about 36%.
Further, in the SI engine of Comparative Example 1, when the compression ratio was set to 10 or more, knocking occurred and operation was impossible, the compression ratio was about 10, and the efficiency ηe was about 28%. Further, in the diesel engine of Comparative Example 2, the compression ratio could be set as high as about 18 to 20, but the efficiency ηe was about 36 to 39%, which is lower than that of the engine according to the present invention. In the diesel engine, the combustion state is unstable because the fuel is directly injected and self-ignited. On the other hand, the engine 100 according to the present invention realizes a stable combustion state.
Further, in the SI engine and the diesel engine of Comparative Examples 1 and 2, it was impossible to operate within a compression ratio range of 10 to 17, whereas the engine 100 according to the present invention was within the above range. Therefore, it is possible to set the compression ratio freely by, for example, finding the compression ratio that maximizes the efficiency by burning in a preferable state.
[0037]
[Another embodiment]
<1> Next, an engine 200 shown in FIG. 6 will be described as another embodiment of the present invention.
The engine 200 is a two-cycle engine, and uses the reciprocating motion of the piston 2 to supply the air A sucked into the crank chamber 40 from the intake port 42 into the main chamber 1 through the scavenging port 41. In the main chamber, compression, combustion / expansion, and exhaust strokes are performed, and the reciprocating motion of the piston 2 is output as the rotational motion of the crankshaft 4 by the connecting rod 6. Complete the cycle. Such a configuration is the same as that of the conventional two-cycle engine, and detailed description thereof is omitted. However, the engine 200 according to the present invention includes fuel in the cylinder head 9 as in the engine 100 shown in FIG. The sub-chamber member 50 is configured to be supplied, and details will be described below.
[0038]
As shown in FIGS. 6 and 7, the sub chamber member 50 is a member on a disk having a space inside. The sub chamber member 50 protrudes upward from the lower portion and the partition 45 on the ring causes the inner space to be a second portion at the center. The sub chamber 20 and the first sub chamber 10 on the outer periphery thereof are partitioned in a state in which a sub chamber communication path 31 communicating with each other is formed. Further, four first communication passages 11 communicating with the main chamber 1 are equally provided in the lower portion of the first sub chamber 10 while being inclined outward and in the outer peripheral direction in the main chamber 1. Further, the four second communication paths 21 communicating with the main chamber 1 also in the lower part of the second sub chamber 20 are equally inclined in the outer and outer peripheral directions in the main chamber 1 like the first communication path. Is provided.
Note that the diameter of the first communication path 11 is 5.0 mm, the diameter of the second communication path 21 is 2.0 mm, and the flow path resistance of the sub chamber communication path 31 is smaller than the flow path resistance of the first communication path 11. It has become.
[0039]
The second sub In the room Is provided with a fuel supply valve 30 and is configured to supply the fuel G to the second sub chamber 20 using the gas pressure of the fuel G stored in a compressed state. In addition, two spark plugs 8 are equally provided above the first sub chamber 10, and are configured to ignite an air-fuel mixture in the first sub chamber described later.
[0040]
By configuring as described above, engine 200 can be operated in the same manner as engine 100 shown in FIG. 1 described in the above embodiment.
That is, the air A supplied to the main chamber is compressed to supply the air A to the first sub chamber passage 10 and the second sub chamber passage 20, and the fuel supply valve 30 is operated so that the fuel G is supplied to the second sub chamber passage 10. By supplying the gas into the chamber 20, an air-fuel mixture in a flammable range is formed in a lean state in the first sub chamber 10, and an air-fuel mixture having an equivalence ratio exceeding the upper limit of combustion is formed in the second sub chamber 20.
Next, the spark plug 8 is activated to burn the air-fuel mixture in the first sub chamber 10, and flame is ejected from the first communication path 11 to the main chamber 1 to form a flame torch F along the cylinder inner wall of the main chamber 1. In addition, the pressure wave generated by the combustion in the precombustion subchamber 11 is propagated to the gas mixture subchamber 20 via the subchamber communication path 31, and the gas mixture in the second subchamber 20 is transferred from the second communication path to the main chamber. 1 is ejected toward the region of the flame torch F, that is, toward the inner wall of the cylinder, to form an ejection mixture M.
[0041]
As a result, similar to the above embodiment, the gas mixture M ejected from the second communication path 21 toward the flame torch F of the main chamber 1 is in a preferable state by the flame torch F ejected from the first communication path 11. In the main chamber 1, the air-fuel mixture M gradually burns, so that combustion in a state close to a so-called diesel cycle (constant pressure cycle) can be realized, and the air is not compressed but the air is compressed. Therefore, knocking can be suppressed, the compression ratio of the engine can be set high, and the efficiency can be improved. In addition, the engine can be operated in an ultra-lean state where the equivalent ratio φ of the mixture of fuel G and air A burned in one cycle is about 0.35, and emissions of CO, HC, NOx, etc. can be reduced. it can.
[0042]
<2> In the above-described embodiment, the configuration in which the pressure wave generated by the combustion in the first sub chamber 10 is propagated to the second sub chamber 20 via the sub chamber communication path 31 as the mixture injection means Y has been described. However, the sub chamber communication path 31 is not provided, and the fuel supply valve is configured to supply the first sub chamber with fuel for forming an air-fuel mixture having an equivalence ratio within the combustible range, and the second sub chamber. Is provided with a fuel injection valve for injecting fuel G at a high pressure, and fuel is injected into the second sub chamber at a high pressure almost simultaneously with igniting the air-fuel mixture in the first sub chamber, and the second connecting path 21 is driven by the momentum of the injection. It is also possible to configure so that the air-fuel mixture is injected from the air.
[0043]
<3> Although the engine using city gas has been described in the above embodiment, the engine of the present application exhibits an excellent effect by configuring an engine using city gas or the like of gaseous fuel. Such gaseous fuel includes gaseous fuels other than hydrocarbons mainly composed of CO and H2 such as hydrogen and propane. Of course, fuel other than gaseous fuel can be used, and for example, gasoline, alcohol, methanol, ethanol, and any fuel can be used.
[0044]
<4> In the above embodiment, when changing the engine speed or load, a rotary valve or the like is provided in the flow path of the air A sucked into the cylinder, and the intake pressure is changed depending on the opening degree of the rotary valve. The load or the rotational speed can be changed by changing the amount of fuel to be supplied.
[0045]
<5> In the above embodiment, the configuration in which only the air A is sucked into the main chamber in the intake stroke has been described. However, a part of the fuel 1 is mixed with the sucked air A and sucked into the main chamber 1. It can also be configured. Further, the fuel G can be supplied to the second sub chamber by the fuel supply valve 30 during the low load operation, and the increased amount of fuel can be supplied to the sucked air A during the high load operation. .
[0046]
<6> In the above-described embodiment, the second communication path 21 may be provided with a reed valve that prevents inflow of fluid from the main chamber 1, and in this case, the air A in the main chamber 1 during the compression stroke. Flows only into the first communication path 10, and air A flows from the first sub chamber 10 into the second sub chamber 20 via the sub chamber communication path 31, so that the flow of air A into the second sub chamber is reduced. As a result, the equivalent ratio of the air-fuel mixture in the second sub-chamber can be more than the upper combustion limit, and the equivalent amount of the air-fuel mixture in the first sub-chamber can be made a lean state near the lower combustion limit within the combustible range, For example, even when the amount of fuel to be supplied is increased during high-load operation, the equivalent ratio of the air-fuel mixture in the first sub chamber can be within the combustible range.
[0047]
<7> In the above embodiment, the fuel is supplied to the second sub chamber by one fuel supply valve 30, and the fuel is supplied to the first sub chamber via the sub chamber communication path. A first fuel supply valve that supplies fuel to the first sub chamber and a second fuel supply valve that supplies fuel to the second sub chamber may be provided separately.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an embodiment of an engine according to the present invention.
2 is a plan view showing a sub chamber member of the engine shown in FIG. 1. FIG.
FIG. 3 is a partial cross-sectional view showing an operating state of the engine shown in FIG.
4 is a partial sectional view showing an operating state of the engine shown in FIG. 1;
FIG. 5 is a chart showing the operation timing of the engine shown in FIG.
FIG. 6 is a schematic view showing another embodiment of the engine according to the present invention.
7 is a plan view showing a sub chamber member of the engine shown in FIG. 6;
[Explanation of symbols]
1 main room
2 piston
3 cylinders
4 Crankshaft
6 Connecting rod
8 Spark plug
10 1st sub-chamber
11 First connection
20 Second subroom
21 Second connection
30 Fuel supply valve
31 Subroom communication path
X Flame injection means
Y Mixture injection means
G fuel
A Air (oxygen-containing gas)

Claims (9)

An engine that burns fuel and oxygen-containing gas in the main chamber, reciprocates the piston in the cylinder, and maintains the rotation of the crankshaft.
A first sub chamber that communicates with the main room via a first communication path; and a second sub chamber that communicates with the main room via a second communication path;
Flame injection means for igniting by forming an air-fuel mixture in the first sub chamber, and for injecting the flame formed in the first sub chamber into the main chamber via the first communication path;
An air-fuel mixture injection means for forming an air-fuel mixture in the second sub-chamber, and for injecting the air-fuel mixture formed in the second sub-chamber into the main chamber via a second communication path;
An engine comprising a reed valve in the second communication path for preventing a flow from the main chamber to the second sub chamber. The mixture injection direction in the main chamber mixture by the injection means, the engine according to the flame spraying means by with claim 1, which consists oriented in the region of the injected flame in the main chamber. A first fuel supply means for supplying a part of the fuel to the first sub chamber; and a spark plug for igniting an air-fuel mixture in the first sub chamber;
The flame injection means activates the first fuel supply means, supplies fuel to the first sub chamber, forms an air-fuel mixture with the oxygen-containing gas in the first sub chamber, activates the spark plug, An air-fuel mixture formed in one subchamber is ignited to form a flame in the first subchamber, and the flame formed in the first subchamber is ejected to the main chamber via the first communication path. Item 3. The engine according to Item 1 or 2 . A second fuel supply means for supplying a part of the fuel to the second sub chamber; and a sub chamber communication passage communicating the first sub chamber and the second sub chamber;
The air-fuel mixture injection means operates the second fuel supply means to supply fuel to the second sub chamber to form an air-fuel mixture with the oxygen-containing gas in the second sub chamber, and to form the first sub chamber The pressure wave of the generated flame is propagated to the second sub chamber through the sub chamber communication path, and the air-fuel mixture formed in the second sub chamber is ejected to the main chamber through the second communication path. The engine according to any one of claims 1 to 3 . A first fuel supply means for supplying a part of the fuel to the first sub chamber;
5. The engine according to claim 4 , further comprising a fuel supply valve that supplies fuel to the sub chamber communication path or to the second sub chamber as the first fuel supply unit and the second fuel supply unit. The engine according to claim 4 or 5 , wherein a flow path resistance of the first communication path is configured to be larger than a flow path resistance of the sub chamber communication path. An engine operating method for burning fuel and oxygen-containing gas in a main chamber, reciprocating a piston in a cylinder, and maintaining rotation of a crankshaft,
The engine is configured by providing a first sub chamber communicating with the main chamber by a first communication path and a second sub chamber communicating with the main chamber by a second communication path,
Forming a flame in the first sub-chamber, performing a flame ejection step of ejecting the flame formed in the first sub-chamber to the main chamber via the first communication path;
A gas mixture is formed in the second sub chamber, and the gas mixture formed in the second sub chamber is ejected to the injected flame region of the main chamber via the second communication path. To do the process,
A method of operating the engine, wherein a reed valve is provided in the second communication path to prevent a flow from the main chamber to the second sub chamber. A first fuel supply means for supplying a part of the fuel to the first sub chamber; and a spark plug for igniting an air-fuel mixture in the first sub chamber;
In order to perform the flame ejection step, the first fuel supply means is operated, fuel is supplied to the first sub chamber to form an air-fuel mixture with the oxygen-containing gas in the first sub chamber, and the spark plug is operated, An air-fuel mixture formed in the first sub chamber is ignited to form a flame in the first sub chamber, and the flame formed in the first sub chamber is ejected to the main chamber through the first communication path. The engine operating method according to claim 7 . A second fuel supply means for supplying a part of the fuel to the second sub chamber; and a sub chamber communication passage communicating the first sub chamber and the second sub chamber;
In order to perform the air-fuel mixture ejection step, the second fuel supply means is operated to supply fuel to the second sub chamber to form an air-fuel mixture together with the oxygen-containing gas in the second sub chamber, and the first sub chamber The pressure wave of the flame formed in the second chamber is propagated to the second sub chamber via the sub chamber communication path, and the air-fuel mixture formed in the second sub chamber is transmitted to the main chamber via the second communication path. The engine operating method according to claim 7 or 8 , wherein the engine is ejected.

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