JP2014227878A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of improving thermal efficiency.SOLUTION: An engine 1 for gas fuel comprises a first piston 41 and a second piston 51 forming a main combustion chamber 11 in which air-fuel mixture containing gas fuel is introduced. A phase control part 60 for coupling the first piston 41 and the second piston 51 controls phases of the first piston 41 and the second piston 51 so that a volume of the main combustion chamber 11 becomes constant from when the piston 41 reaches an upper dead center until the second piston 51 reaches the upper dead center, after the air-fuel mixture in the main combustion chamber 11 is ignited by a spark plug 15. Thereby, pressure in the main combustion chamber 11 after the air-fuel mixture in the main combustion chamber 11 is ignited becomes higher than pressure in a main combustion chamber of an engine for gas fuel in which two pistons reach the upper dead center at the same time. Accordingly, a labor outputted by the engine 1 for gas fuel becomes comparatively large, so that thermal efficiency can be improved.

Description

  The present invention relates to an internal combustion engine, and more particularly, to an internal combustion engine having two reciprocating pistons for one combustion chamber.

  Conventionally, a double piston engine in which the volume of one combustion chamber is changed by reciprocation of two pistons is known. In the double piston engine, when the stroke of the piston is the same as that of a single piston engine having one piston for one combustion chamber, the volume of the combustion chamber when the air-fuel mixture is supplied is doubled. The thermal energy generated in each combustion process is doubled. For example, Patent Document 1 describes a piston-facing internal combustion engine that includes two pistons whose end faces of a piston forming a combustion chamber face each other.

JP 2007-046534 A

  However, in the piston-opposed internal combustion engine described in Patent Document 1, the area of the inner wall forming the combustion chamber is relatively large. For this reason, there is a concern that the heat loss caused by the temperature difference between the temperature of the combustion chamber and the inner wall becomes large and the thermal efficiency is lowered.

  An object of the present invention is to provide an internal combustion engine capable of improving thermal efficiency.

  The internal combustion engine of the present invention includes one piston that can reciprocate, the other piston that can reciprocate in conjunction with the movement of one piston, a cylinder that houses the one piston and the other piston, and one piston An ignition means for igniting the fuel introduced into the main combustion chamber formed by the other piston and the cylinder, and a phase difference control means connected to the one piston and the other piston, and the phase difference control means Is characterized in that after the fuel introduced into the main combustion chamber is ignited by the ignition means, the phase of one piston and the phase of the other piston are controlled so that the volume of the main combustion chamber is constant for a predetermined time. To do.

  In the internal combustion engine of the present invention, one piston and the other piston are connected by phase difference control means so as to be interlocked. The phase difference control means provides a phase difference between one piston and the other piston so that the volume of the main combustion chamber is constant for a predetermined time after the fuel is ignited. Here, the “phase” of the piston is a value indicating the position between the top dead center and the bottom dead center in the reciprocating motion of the piston in the cylinder. In the internal combustion engine of the present invention, The phase control means controls so that the phase of the piston and the phase of the other piston are different. Thereby, the time for which the volume of the main combustion chamber is constant becomes relatively long, and the pressure of the main combustion chamber becomes relatively large. Therefore, the amount of work that the internal combustion engine performs on the outside increases, and the thermal efficiency of the internal combustion engine can be improved.

1 is a schematic diagram of an internal combustion engine according to a first embodiment of the present invention. It is a schematic diagram explaining the effect | action in the internal combustion engine by 1st Embodiment of this invention, and a characteristic view which shows the time change of the volume of a main combustion chamber. FIG. 3 is a schematic diagram different from FIG. 2 for explaining the operation of the internal combustion engine according to the first embodiment of the present invention, and a characteristic diagram showing a temporal change in the volume of the main combustion chamber. FIG. 5 is a schematic diagram different from FIGS. 2 and 3 for explaining the operation of the internal combustion engine according to the first embodiment of the present invention, and a characteristic diagram showing a time change of the volume of the main combustion chamber. FIG. 5 is a schematic diagram different from FIGS. 2 to 4 for explaining the operation of the internal combustion engine according to the first embodiment of the present invention, and a characteristic diagram showing a temporal change in the volume of the main combustion chamber. FIG. 6 is a characteristic diagram showing a change over time in the distance between one piston and the other piston in the internal combustion engine according to the first embodiment of the present invention. It is a pv diagram in the internal combustion engine by a 1st embodiment of the present invention. It is a schematic diagram of the internal combustion engine by 2nd Embodiment of this invention. It is a pv diagram in an internal combustion engine by other embodiments of the present invention.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
An internal combustion engine according to a first embodiment of the present invention is shown in FIGS. A gas fuel engine 1 as an “internal combustion engine” is a so-called four-cycle engine, in which gas fuel supplied from a gas fuel fuel tank (not shown) is combusted in the main combustion chamber 11, and the pressure change in the main combustion chamber 11. The rotational torque is output from the operation of the first piston 41 and the second piston 51 by the above. As shown in FIG. 1, the gaseous fuel engine 1 includes a cylinder 10, a spark plug 15, an intake system 20, an exhaust system 30, a first piston unit 40, a second piston unit 50, and a phase control unit 60. The An arrow F1 in FIG. 1 indicates the flow of the air-fuel mixture from the intake system 20 to the main combustion chamber 11. Further, an arrow F2 in FIG. 1 indicates the flow of the exhaust led out from the main combustion chamber 11 through the exhaust system 30 to the outside.

  The cylinder 10 is a bottomed cylindrical metal member having bottoms at both ends, and accommodates the first piston part 40 and the second piston part 50 therein. The cylinder 10 includes a piston surface 411 on the second piston portion 50 side of the first piston 41 included in the first piston portion 40, a piston surface 511 on the first piston portion 40 side of the second piston 51 included in the second piston portion 50, The main combustion chamber 11 is formed by inner wall surfaces 101 and 102 on which the first piston 41 and the second piston 51 slide. A side wall 103 having an inner wall surface 101 is provided with a spark plug 15, an intake system 20, and an exhaust system 30 as “ignition means” for igniting an air-fuel mixture in the main combustion chamber 11. The piston surface 411 corresponds to “an end surface of one piston” recited in the claims. The piston surface 511 corresponds to “an end surface of the other piston” recited in the claims.

  The intake system 20 includes an intake valve 21 and an intake pipe 22. The intake valve 21 contacts or separates from a valve seat 104 formed on the inner wall surface 101 of the cylinder 10. The intake pipe 22 supplies a mixture of gaseous fuel and air to the main combustion chamber 11 when the intake valve 21 is separated from the valve seat 104.

  The spark plug 15 is provided between the intake valve 21 and the exhaust valve 31. The spark plug 15 ignites the air-fuel mixture supplied to the main combustion chamber 11 in accordance with an instruction from a control unit (not shown).

  The exhaust system 30 includes an exhaust valve 31 and an exhaust pipe 32. The exhaust valve 31 contacts or separates from a valve seat 105 formed on the inner wall surface 101 of the cylinder 10. The exhaust pipe 32 discharges the gas after combustion in the main combustion chamber 11 to the outside when the exhaust valve 31 is separated from the valve seat 105 after the air-fuel mixture in the main combustion chamber 11 is ignited by the spark plug 15. .

  The first piston portion 40 includes a first piston 41, a first connecting rod 42, a first crank 43, a first crankshaft 44, and the like. The first piston unit 40 outputs the rotational motion of the first crankshaft 44 to the outside using the pressure change in the main combustion chamber 11.

  The first piston 41 is formed in a substantially cylindrical shape, and is provided inside the cylinder 10 so as to be capable of reciprocating with respect to the cylinder 10 while sliding with the inner wall surfaces 101 and 102. One end of the first connecting rod 42 is connected to the first piston 41 as “one piston”. A first crank 43 is connected to the other end of the first connecting rod 42.

  The first crank 43 is accommodated in a first crank chamber 13 formed in one end of the cylinder 10. The first crank 43 and the first connecting rod 42 convert the reciprocating motion of the first piston 41 into the rotational motion of the first crankshaft 44. An opposite end 441 of the first crankshaft 44 that is connected to the first crank 43 projects from the through hole 107 formed in the side wall 106 of the cylinder 10 to the outside of the cylinder 10. The end 441 is inserted into the phase control unit 60.

  The second piston portion 50 includes a second piston 51, a second connecting rod 52, a second crank 53, a second crankshaft 54, and the like. The second piston unit 50 outputs the rotational motion of the second crankshaft 54 to the outside using the pressure change in the main combustion chamber 11.

  The second piston 51 is formed in a substantially cylindrical shape, and is provided inside the cylinder 10 so as to reciprocate on the same axis as the first piston 41 with respect to the cylinder 10 while sliding with the inner wall surfaces 101 and 102. The second piston 51 is provided such that the piston surface 511 faces the piston surface 411 of the first piston 41. One end of the second connecting rod 52 is connected to the second piston 51 as “the other piston”. A second crank 53 is connected to the other end of the second connecting rod 52.

  The second crank 53 is accommodated in a second crank chamber 14 formed in the other end of the cylinder 10. The second crank 53 converts the reciprocating motion of the second piston 51 into the rotational motion of the second crankshaft 54. The opposite end 541 of the second crankshaft 54 that is connected to the second crank 53 protrudes from the through hole 108 formed in the side wall 106 of the cylinder 10 to the outside of the cylinder 10. The end 541 is inserted into the phase control unit 60.

  The phase control unit 60 includes a timing belt 61, a housing 62, and the like. The timing belt 61 accommodated in the housing 62 connects the end 441 of the first crankshaft 44 and the end 541 of the second crankshaft 54 in the housing 62. Thereby, the 1st piston 41 and the 2nd piston 51 interlock. Specifically, the timing belt 61 has an end portion of the first crankshaft 44 such that when the first piston 41 is at the top dead center, the second piston 51 is located on the way from the bottom dead center to the top dead center. 441 is connected to the end 541 of the second crankshaft 54. The phase control unit 60 corresponds to a “phase control unit” recited in the claims.

Next, the combustion process and effects of the gaseous fuel engine 1 will be described with reference to FIGS.
2A, 3A, 4A, and 5A show the relative positions of the first piston 41 and the second piston 51 with respect to the cylinder 10 in the combustion process of the gaseous fuel engine 1. FIG. 2 (b), 3 (b), 4 (b), and 5 (b) show changes over time in the volume of the main combustion chamber 11. FIG. 2 (a), 3 (a), 4 (a), and 5 (a), for convenience of explanation, the center of the cylinder 10 is a center line C, and the top dead center position of the first piston 41 is a dotted line. P1 and the position of the top dead center of the second piston 51 are indicated by a dotted line P2. In the gaseous fuel engine 1, the top dead center of the first piston 41 and the top dead center of the second piston 51 are located at the position of the dotted line P1 and the second piston 51 is at the dotted line P2. The volume of the main combustion chamber 11 formed when in the position is from the volume v0 which is the minimum volume of the main combustion chamber 11 shown in FIGS. 2 (b), 3 (b), 4 (b) and 5 (b). It is provided to be smaller. That is, the first piston portion 40 and the second piston portion 50 are pistons in a gas fuel engine as a comparative example, which will be described later, in which two opposing pistons simultaneously reach top dead center when the air-fuel mixture in the main combustion chamber burns. The stroke amounts of the first piston 41 and the second piston 51 are provided to be larger than the stroke amount. 2 (a), 3 (a), 4 (a), and 5 (a), the direction of movement of the first piston 41 at each time is indicated by the white arrow M1 and the movement of the second piston 51. The direction is indicated by a white arrow M2.

  FIG. 6 shows a change over time in the distance between the piston surface 411 of the first piston 41 and the piston surface 511 of the second piston 51 in the combustion process of the gaseous fuel engine 1. In FIG. 6, the position of the piston surface 411 at the bottom dead center of the first piston 41 is set to 0, the time change of the position of the piston surface 411 of the first piston 41 is represented by the solid line L1, and the position of the piston surface 511 of the second piston 51 Is shown by a solid line L2. In FIG. 6, the position of the center line C of the cylinder 10 shown in FIGS. 2 (a), 3 (a), 4 (a), and 5 (a) is indicated by the dotted line L0, and the position of the top dead center of the first piston 41 is indicated. A dotted line L10 and the position of the top dead center of the second piston 51 are indicated by a dotted line L20.

  The intake valve 21 is separated from the valve seat 104 and a mixture of gaseous fuel and air is supplied into the cylinder 10. After the intake valve 21 contacts the valve seat 104, the first piston 41 moves toward the top dead center (after time t0 in FIG. 6). Furthermore, when the second piston 51 starts moving toward top dead center, the volume of the main combustion chamber 11 decreases due to the proximity of the first piston 41 and the second piston 51 (for example, time t1 in FIG. 6). The pressure of the air-fuel mixture in the main combustion chamber 11 increases. At this time, as shown in FIG. 2A, the piston surface 411 of the first piston 41 is positioned closer to the center line C of the cylinder 10 than the piston surface 511 of the second piston 51.

The air-fuel mixture in the main combustion chamber 11 is ignited by the ignition plug 15 while the pressure of the air-fuel mixture in the main combustion chamber 11 is increased by the movement of the first piston 41 and the second piston 51. Specifically, as shown in FIG. 3B, ignition is performed at time t2 before time t3 when the first piston 41 reaches top dead center.
After the air-fuel mixture is ignited, the first piston 41 reaches top dead center at time t3 (FIG. 3 (a)). At this time, as shown at time t <b> 3 in FIG. 3B, the volume of the main combustion chamber 11 becomes a minimum value in the combustion process of the gaseous fuel engine 1. When the first piston 41 reaches the top dead center, the second piston 51 is in a position where it rises from the bottom dead center to the top dead center.

  Next, the second piston 51 reaches the top dead center at time t4 during the movement of the first piston 41 from the top dead center to the bottom dead center (FIG. 4A). In the gaseous fuel engine 1, the main combustion chamber 11 extends from time t3 when the first piston 41 shown in FIG. 3 reaches top dead center to time t4 when the second piston 51 shown in FIG. 4 reaches top dead center. The phases of the first piston 41 and the second piston 51 are adjusted by the phase control unit 60 so that the volume of the first piston 41 and the second piston 51 becomes constant.

Next, the second piston 51 starts moving from the top dead center toward the bottom dead center. At this time, as shown in FIG. 6, the first piston 41 is also moved from the top dead center to the bottom dead center. Thereby, as shown after time t4 in FIG. 6, the piston surface 411 of the first piston 41 and the piston surface 511 of the second piston 51 move away from each other, and the volume of the main combustion chamber 11 is as shown in FIG. As shown in b), it increases after time t4.
Thus, in the gaseous fuel engine 1, the phases of the first piston 41 and the second piston 51 are controlled so that the second piston 51 reaches the top dead center after the first piston 41 reaches the top dead center. Yes.

  FIG. 7 shows a pv diagram in the combustion process of the gaseous fuel engine 1 according to the first embodiment. In FIG. 7, the relationship between the pressure p and the volume v of the main combustion chamber 11 in the gaseous fuel engine 1 is indicated by a solid line L3. As a comparative example, a dotted line L4 indicates the relationship between the pressure p and the volume v of the main combustion chamber in a gas fuel engine in which two opposing pistons simultaneously reach top dead center during combustion of the air-fuel mixture in the main combustion chamber. .

  In the gas fuel engine of the comparative example, when the mixture in the main combustion chamber is ignited and the two pistons reach the top dead center, the volume of the main combustion chamber becomes the smallest volume v0. After the two pistons reach the top dead center, the two pistons go from the top dead center to the bottom dead center, so the time during which the volume of the main combustion chamber is the volume v0 is relatively short. The pressure of the combustion chamber becomes maximum at the pressure p2 when the volume of the main combustion chamber starts to become larger than the volume v0.

  On the other hand, in the gas fuel engine 1, a phase difference is provided between the first piston 41 and the second piston 51, and the stroke amounts of the first piston 41 and the second piston 51 are set to the pistons of the gas fuel engine of the comparative example. From the time t3 when the first piston 41 is located at the top dead center to the time t4 when the second piston 51 is located at the top dead center, the volume of the main combustion chamber 11 is the same as that of the comparative example. It becomes constant at the same volume v0 as the minimum volume in the engine for gaseous fuel. In the gas fuel engine 1, the time in which the volume of the main combustion chamber 11 becomes the volume v0 is longer than that of the gas fuel engine of the comparative example, and therefore the pressure in the main combustion chamber 11 is generated in the gas fuel engine of the comparative example. The pressure p1 is greater than the maximum pressure p2. Thereby, the work amount W1 (= ∫p1dv) output from the gaseous fuel engine 1 in the combustion process becomes larger than the work amount W2 (= ∫p2dv) output from the gaseous fuel engine of the comparative example. Therefore, the thermal efficiency of the gaseous fuel engine 1 can be improved.

  In the gas fuel engine 1, as shown in FIG. 7, the minimum volume of the main combustion chamber 11 is the minimum volume of the main combustion chamber of the gas fuel engine in which the two pistons reach top dead center at the same time. In order to make it the same as the volume v0, the stroke amount of the first piston 41 and the second piston 51 is set to be larger than the stroke amounts of the two pistons of the gas fuel engine in which the two pistons reach the top dead center at the same time. It has been. Thereby, since the compression ratio of the main combustion chamber 11 increases, the maximum pressure of the main combustion chamber 11 can be further increased. Therefore, the thermal efficiency of the gaseous fuel engine 1 can be further improved.

(Second Embodiment)
Next, an internal combustion engine according to a second embodiment of the present invention will be described with reference to FIG. The second embodiment differs from the first embodiment in that it includes a cavity that forms a preliminary combustion chamber. In addition, the same code | symbol is attached | subjected to the site | part substantially the same as 1st Embodiment, and description is abbreviate | omitted. 8 indicates the flow of the air-fuel mixture from the intake system 20 to the auxiliary combustion chamber 12. Further, an arrow F4 in FIG. 8 indicates the flow of the exhaust led out from the auxiliary combustion chamber 12 through the exhaust system 30 to the outside.

  The gaseous fuel engine 2 according to the second embodiment has a preliminary combustion chamber 12 communicating with the main combustion chamber 11. The preliminary combustion chamber 12 is formed by a substantially rectangular parallelepiped cavity 121, and communicates with the main combustion chamber 11 through a communication passage 109 formed in the side wall 103.

  The cavity 121 is provided with a spark plug 15, a valve seat 122 capable of contacting the intake valve 21, and a valve seat 123 capable of contacting the exhaust valve 31 on the side wall. The spark plug 15 is provided on the side wall 124 of the cavity 121 that faces the first piston 41 that reaches the top dead center first of the first piston 41 and the second piston 51. The cavity 121 corresponds to a “preliminary combustion chamber forming portion” described in the claims.

In the gaseous fuel engine 2, the intake valve 21 is separated from the valve seat 122 and the air-fuel mixture is supplied to the preliminary combustion chamber 12. The air-fuel mixture supplied to the preliminary combustion chamber 12 diffuses into the main combustion chamber 11 via the communication path 109. Thereby, the air fuel mixture in the main combustion chamber 11 is in a state where the gas fuel concentration is relatively lower than the air fuel mixture in the preliminary combustion chamber 12 where the gas fuel concentration is relatively high.
While the first piston 41 and the second piston 51 are moving from the bottom dead center toward the top dead center, the air-fuel mixture in the preliminary combustion chamber 12 is ignited by the spark plug 15. The air-fuel mixture in the preliminary combustion chamber 12 has a relatively high concentration of gaseous fuel as described above, and the flame generated in the preliminary combustion chamber 12 by the spark plug 15 diffuses into a spherical shape, for example. It propagates to the air-fuel mixture in the passage 109 and the air-fuel mixture in the main combustion chamber 11. The flame in the preliminary combustion chamber 12 propagates to the air-fuel mixture in the main combustion chamber 11 when the first piston 41 is moving from the top dead center toward the bottom dead center.

  In the gaseous fuel engine 2, first, an air-fuel mixture having a relatively high concentration of gaseous fuel in the preliminary combustion chamber 12 communicating with the main combustion chamber 11 is ignited. The ignited air-fuel mixture in the preliminary combustion chamber 12 becomes spatial combustion due to the spread of the flame centering on the ignition plug 15, and the spatial combustion is propagated to the air-fuel mixture in the main combustion chamber 11 through the communication passage 109. In the main combustion chamber 11, the combustion spreads as a surface, so that the entire air-fuel mixture in the main combustion chamber 11 burns in a short time compared to point combustion. As a result, it is possible to improve the combustion efficiency, which is the ratio of the amount of energy generated by combustion to the amount of combustible energy supplied to the main combustion chamber 11 and the preliminary combustion chamber 12. Therefore, in the gaseous fuel engine 2 according to the second embodiment, in addition to the effects of the first embodiment, the combustion efficiency can be further improved.

  In the gaseous fuel engine 2 according to the second embodiment, the spark plug 15 is provided on the side wall 124 of the cavity 121 that faces the first piston 41 that reaches the top dead center first. As a result, the relative speed between the moving speed from the top dead center to the bottom dead center of the first piston 41 and the propagation speed of the flame is reduced, so that the pressure change propagating from the preliminary combustion chamber 12 to the main combustion chamber 11 is top dead. Direct action on the piston surface 411 of the first piston 41 toward the point can be prevented.

(Other embodiments)
(A) In the above-described embodiment, the “internal combustion engine” is a four-cycle engine for gaseous fuel. However, the type of “internal combustion engine” is not limited to this. The supplied fuel may be a liquid fuel such as gasoline. A two-cycle engine may also be used.

  (A) In the above-described embodiment, the first piston and the second piston are provided so as to be reciprocally movable on the same axis, and the piston surface of the second piston is provided so as to face the piston surface of the first piston. However, the positional relationship between the first piston and the second piston is not limited to this. For example, the first piston and the second piston may move in parallel, and the main combustion chamber may be formed on the top dead center side of the first piston and the second piston.

  (A) In the above-described embodiment, the phase control unit is configured by a timing belt that connects two crankshafts, a housing that houses the timing belt, and the like. However, the member which comprises a phase control part is not limited to this. For example, you may control the phase of a 1st piston and a 2nd piston with generators, such as an alternator.

  (C) In the above-described embodiment, the air-fuel mixture in the main combustion chamber or the preliminary combustion chamber is ignited by the spark plug. However, the “ignition means” is not limited to this. A torch or a pulse jet may be used.

  (D) In the second embodiment, the spark plug is provided on the side wall of the cavity facing the first piston that reaches the top dead center first. However, the place where the spark plug is provided is not limited to this.

(E) In the above-described embodiment, the stroke amounts of the first piston and the second piston are larger than the stroke amounts of the two pistons of the gas fuel engine in which the two pistons reach the top dead center at the same time. However, the stroke amounts of the first piston and the second piston are not limited to this. The stroke amounts of the first piston and the second piston may be the same as the stroke amounts of the two pistons of the gas fuel engine in which the two pistons reach the top dead center at the same time.
FIG. 9 shows the positions of the first piston and the second piston while making the stroke amounts of the first piston and the second piston the same as the stroke amounts of the two pistons of the gas fuel engine in which the two pistons reach the top dead center at the same time. A pv diagram of the gas fuel engine of the present invention providing a phase difference is indicated by a solid line L5. The dotted line L4 indicates the pressure p and volume v of the main combustion chamber in the gas fuel engine in which two opposing pistons reach the top dead center at the same time during combustion of the air-fuel mixture in the main combustion chamber as a comparative example shown in FIG. Relationship.
As shown in FIG. 9, in the gas fuel engine of the present invention, the minimum volume v1 of the main combustion chamber is larger than the minimum volume v0 of the main combustion chamber in the gas fuel engine of the comparative example. The maximum volume v2 of the main combustion chamber in the gas fuel engine of the present invention is smaller than the maximum volume v3 of the main combustion chamber in the gas fuel engine of the comparative example. However, in the gas fuel engine of the present invention, the maximum pressure p3 when the volume of the main combustion chamber is volume v1 is the pressure p2 when the volume of the main combustion chamber in the gas fuel engine of the comparative example is volume v0. Compared to larger. Thereby, the work output from the gas fuel engine of the present invention in the combustion process becomes larger than the work output from the gas fuel engine of the comparative example. Therefore, in the gas fuel engine of the present invention, even when the stroke amounts of the first piston and the second piston are the same as the stroke amounts of the two pistons of the gas fuel engine in which the two pistons reach the top dead center at the same time. Thermal efficiency can be improved.

  (F) In the above-described embodiment, the mixture of fuel and air is introduced into the main combustion chamber via the intake system. However, the fuel introduction means for introducing fuel into the main combustion chamber is not limited to this. There may be direct injection for injecting only fuel directly into the main combustion chamber and fuel introduction means for supplying air to the main combustion chamber via a separate supply pipe.

  Thus, the present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the gist thereof.

1, 2 ... Engine for gaseous fuel (internal combustion engine),
10 ... Cylinder,
11 ... main combustion chamber,
15 ... Spark plug (ignition means),
41 ... 1st piston (one piston),
51 ・ ・ ・ Second piston (the other piston),
60: Phase control unit (phase control means).

Claims (6)

One piston (41) capable of reciprocating,
The other piston (51) capable of reciprocating in conjunction with the movement of the one piston;
A cylinder (10) for accommodating the one piston and the other piston;
Ignition means (15) for igniting fuel introduced into a main combustion chamber (11) formed by the one piston, the other piston, and the cylinder;
The one piston is connected to the one piston and the other piston, and after the fuel introduced into the main combustion chamber is ignited by the ignition means, the volume of the main combustion chamber is constant for a predetermined time. And a phase difference control means (60) for controlling the phase of the other piston and the phase of the other piston,
An internal combustion engine comprising:   The ignition means ignites the fuel in the main combustion chamber after the fuel is introduced into the main combustion chamber and before the one piston and the other piston reach top dead center. Item 6. The internal combustion engine according to Item 1.   The one piston and the other piston are provided such that an end face (411) of the one piston forming the main combustion chamber faces an end face (511) of the other piston forming the main combustion chamber. The internal combustion engine according to claim 1 or 2, characterized by the above. A preliminary combustion chamber forming part (121) for forming a preliminary combustion chamber (12) communicating with the main combustion chamber;
The internal combustion engine according to any one of claims 1 to 3, wherein the ignition means is provided in the preliminary combustion chamber forming portion.   The ignition means includes the preliminary combustion chamber forming portion that faces the piston that first reaches top dead center after the fuel introduced into the main combustion chamber of the one piston and the other piston is ignited. The internal combustion engine according to claim 4, wherein the internal combustion engine is provided on a side wall of the engine.   The phase difference control means comprises a timing belt (61) for connecting the crankshaft (44) of the one piston and the crankshaft (54) of the other piston, and a housing (62) for housing the timing belt. The internal combustion engine according to any one of claims 1 to 5, wherein

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