JP2012047115A - Auxiliary chamber type gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an auxiliary chamber type gas engine, in which an auxiliary chamber is hardly super-cooled on starting the engine and a plug holder is easily cooled during a high-load period of the engine.SOLUTION: The auxiliary chamber type gas engine 1 includes a piston 6 movably stored in a cylinder block, a cylinder head 3 cooperating with the piston 6 and the cylinder block to segment a main combustion chamber 10, and a plug holder 4 to be inserted to a mount hole 3c of the cylinder head 3 and having an ignition plug 5 attached thereto. The plug holder 4 includes an auxiliary chamber 11 where the fuel gas is supplied and a nozzle hole 4a communicating between the auxiliary chamber 11 and the main combustion chamber 10. A thermally conductive member 9 is disposed between the mount hole 3c and the plug holder 4, for allowing transfer of heat from the plug holder 4 to the cylinder head 3. The thermally conductive member 9 has a portion where a bimetal that deforms responding to heat is included and a contact area with the plug holder 4 is increased when the temperature is raised to a deformation temperature.

Description

  The present invention relates to a sub-chamber gas engine.

  The sub-chamber gas engine includes a piston movably housed in a cylinder block, a cylinder head that cooperates with the piston and the cylinder block to define a main combustion chamber, a cylinder head mounting hole, and an ignition plug. It has a plug holder to be attached (see Patent Document 1). The plug holder is formed with a sub chamber to which fuel gas is supplied, and an injection hole communicating the sub chamber and the main combustion chamber. An annular heat conducting member is provided in the mounting hole of the cylinder head. The inner peripheral surface of the heat conducting member is in contact with the plug holder, and the outer peripheral surface of the heat conducting member is in contact with the cylinder head.

  Therefore, when the plug holder becomes hotter than the cylinder head, the heat of the plug holder moves to the cylinder head via the heat conducting member. Therefore, the plug holder can be constantly cooled by the heat conducting member. In this way, the plug holder can be a heat source, and the fuel gas in the main combustion chamber can be ignited, and the life reduction of the spark plug due to overheating of the plug holder can be suppressed.

JP 2009-236017 A

  However, when the plug holder is cooled at the time of starting the engine or the like, misfire occurs in the sub chamber in the plug holder, and combustion instability occurs. Therefore, there is a need for a sub-chamber gas engine in which the sub-chamber is difficult to be overcooled when the engine is started and the plug holder is easily cooled when the engine is heavily loaded.

  In order to solve the above-mentioned problems, the present invention is a sub-chamber type gas engine having a structure as described in each claim. According to one aspect, the present invention includes a piston that is movably housed in a cylinder block, a cylinder head that defines a main combustion chamber in cooperation with the piston and the cylinder block, and an attachment formed in a sub-chamber gas engine. A plug holder is inserted into the hole and to which a spark plug is attached. The plug holder is formed with a sub chamber to which fuel gas is supplied, and an injection hole for communicating the sub chamber and the main combustion chamber. Between the mounting hole of the sub-chamber type gas engine and the plug holder, a heat conducting member that can allow heat to move from the plug holder to the sub-chamber type gas engine is provided. The heat conducting member includes a bimetal that deforms in response to heat, and has a portion that increases in contact area with at least one of the plug holder and the sub-chamber gas engine by raising the deformation temperature.

  Therefore, when the temperature of the heat conducting member is low, such as when the engine is started, the contact area with the plug holder or the cylinder head is small (or zero). Therefore, it is difficult for the heat of the plug holder to be transmitted to the sub-chamber gas engine, and the plug holder can be prevented from being overcooled by the heat conducting member. Thus, misfire in the sub chamber in the plug holder is reduced, and combustion in the sub chamber is stabilized.

  On the other hand, the heat conducting member has a large contact area with the plug holder or the sub-chamber type gas engine when the temperature at a high engine load is high. Thereby, the heat of the plug holder is easily transmitted to the sub-chamber gas engine, and the plug holder is easily cooled. Thus, it can be suppressed that the plug holder becomes a heat source and the fuel gas in the main combustion chamber is ignited early (pre-ignition). Or it can be suppressed that the durability of the spark plug decreases due to the high temperature of the spark plug, or the efficiency of intake into the sub chamber decreases due to the high temperature of the plug holder.

It is sectional drawing of a subchamber type gas engine. It is an expanded sectional view of the gas engine in the sub chamber vicinity. It is an expanded sectional view of the gas engine in the subchamber neighborhood after temperature rise. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view taken along line VV in FIG. 4. It is an expanded sectional view of the gas engine which concerns on the other form in the sub chamber vicinity. It is an expanded sectional view of the gas engine of Drawing 6 in the 1st state. It is an expanded sectional view of the gas engine of Drawing 6 in the 2nd state. It is an expanded sectional view of the gas engine which concerns on the other form in the sub chamber vicinity. FIG. 10 is a cross-sectional view of the gas engine of FIG. 9 after a temperature rise. FIG. 10 is a cross-sectional view taken along line XI-XI in FIG. 9. It is an expanded sectional view of the gas engine which concerns on the other form in the sub chamber vicinity. It is sectional drawing of the gas engine of FIG. 12 after temperature rise. It is a top view of the deformation member of FIG.

  One embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the gas engine 1 is a vehicle internal combustion engine for generating power for the vehicle, for example. The gas engine 1 is a sub-chamber gas engine and includes a cylinder block 2, a cylinder head 3, and a plug holder 4.

  A bore 2a is formed in the cylinder block 2 as shown in FIG. A piston 6 is accommodated in the bore 2a so as to be capable of linear motion. The piston 6 is connected to the crankshaft 8 by a connecting rod 7. The linear motion of the piston 6 is converted into the rotational motion of the crankshaft 8 by the connecting rod 7.

  The cylinder head 3 is connected to the cylinder block 2 as shown in FIG. A main combustion chamber 10 is defined by the cylinder block 2, the cylinder head 3 and the piston 6. The cylinder head 3 is formed with an intake port 3 a and an exhaust port 3 b that communicate with the main combustion chamber 10. An intake valve 12 is provided in the intake port 3a, and an exhaust valve 13 is provided in the exhaust port 3b. By opening the intake valve 12, a lean mixed gas containing fuel gas is supplied from the intake port 3a to the main combustion chamber 10. By opening the exhaust valve 13, exhaust gas is discharged from the main combustion chamber 10 to the exhaust port 3b.

  The plug holder (sub chamber member) 4 has a cylindrical shape as shown in FIGS. 1 and 2 and is inserted into a mounting hole 3 c formed in the cylinder head 3. One end of the plug holder 4 is closed by the spark plug 5, and the other end is closed by the tip 4b. Therefore, a sub chamber 11 is defined inside the plug holder 4.

  As shown in FIG. 2, the sub-chamber 11 is supplied with a rich mixed gas containing fuel gas from the pipe 15. The rich mixed gas has a higher fuel to air ratio than the lean mixed gas supplied to the main combustion chamber 10. The fuel gas includes, for example, natural gas. The tip end 4 b of the plug holder 4 is hemispherical and protrudes from the cylinder head 3 to face the main combustion chamber 10. A plurality of nozzle holes 4 a that communicate the sub chamber 11 and the main combustion chamber 10 are formed in the distal end portion 4 b.

  As shown in FIG. 2, in the vicinity of the end of the mounting hole 3 c, a flange portion 4 f is formed on the plug holder 4, and a head protruding portion 3 d is formed on the cylinder head 3. The flange portion 4 f is formed on the outer surface of the plug holder 4. The head protruding portion 3d protrudes from the lower end of the constituent wall surface 3e of the mounting hole 3c to the inner peripheral side. An annular gasket 14 is interposed between the flange portion 4f and the head protruding portion 3d, and the plug holder 4 is positioned with respect to the mounting hole 3c.

  On the outer peripheral surface of the plug holder 4, a recess 4e in which the heat conducting member 9 is installed is formed as shown in FIG. The recess 4 e is located near the tip of the spark plug 5. The recess 4 e is formed on the entire outer surface of the plug holder 4. An upper wall surface 4c constituting the upper surface of the recess 4e is formed on the upper side of the recess 4e. A lower side wall surface 4d constituting the lower surface of the concave portion 4e is formed below the concave portion 4e (that is, the side close to the sub chamber 11). The upper and lower side wall surfaces 4c and 4d extend from the bottom surface of the recess 4e toward the constituent wall surface 3e of the mounting hole 3c.

  As shown in FIGS. 2 and 4, the heat conducting member 9 includes a contact member 9 b and a plurality of deformation members 9 a. The contact member 9b is formed from a material having high thermal conductivity, such as a metal. The contact member 9b is C-shaped and has a hole 9b3 at the center. The contact member 9b is elastically deformed and installed in the recess 4e, and the plug holder 4 penetrates the hole 9b3 in the vertical direction. The outer peripheral surface of the contact member 9b is in contact with the constituent wall surface 3e of the mounting hole 3c, and preferably the substantially entire length of the outer peripheral surface of the contact member 9b is in contact with the constituent wall surface 3e. The inner peripheral surface of the contact member 9 b is close to the plug holder 4, and preferably the entire inner peripheral surface does not contact the bottom surface of the recess 4 e of the plug holder 4.

  As shown in FIGS. 3 to 5, the deformable member 9 a is formed from a bimetal that deforms depending on the temperature. The plurality of deformable members 9a are attached to the lower wall surface 4d at predetermined intervals. The contact member 9b is installed on the deformation member 9a. The deformation member 9a has a flat plate shape at a normal temperature. In this case, as shown in FIG. 2, the contact member 9b is separated from the upper wall surface 4c by gravity. The deformable member 9a deforms (snaps) in the thickness direction by reaching a preset deformation temperature (for example, 200 to 700 ° C.). Thereby, as shown in FIG. 3, the deformation member 9a lifts the contact member 9b, and the upper surface of the contact member 9b is pressed against the upper wall surface 4c.

  As shown in FIG. 2, when the rich mixed gas is supplied to the sub chamber 11 and the rich mixed gas is ignited by the spark plug 5, a flame is generated. When the flame is generated, the pressure in the sub chamber 11 becomes higher than the pressure in the main combustion chamber 10, and the torch flame is ejected from the sub chamber 11 to the main combustion chamber 10 through the nozzle hole 4a. The lean mixed gas in the main combustion chamber 10 is burned by the torch flame.

  As shown in FIG. 1, when the lean mixed gas in the main combustion chamber 10 burns, the pressure in the main combustion chamber 10 changes and the piston 6 moves up and down. When the piston 6 moves up and down, the intake valve 12 and the exhaust valve 13 open and close. As a result, fresh air is taken into the main combustion chamber 10 and exhaust gas is discharged from the main combustion chamber 10. Accordingly, intake, compression, combustion / expansion, and exhaust strokes are performed in the main combustion chamber 10, and the piston 6 moves up and down. The vertical movement of the piston 6 is converted into a rotational movement of the crankshaft 8 by the connecting rod 7.

  During a predetermined time immediately after starting the engine and when the engine load is small, as shown in FIG. 2, the temperature of the heat conducting member 9 is below the deformation temperature (for example, 200 to 700 ° C.). Therefore, the deformation member 9a is not deformed or the deformation amount is small. At this time, the upper surface of the contact member 9b is separated from the upper wall surface 4c. The outer peripheral surface of the contact member 9b is in contact with the cylinder head 3 in whole or in part. The lower surface of the contact member 9b is installed on the lower side wall surface 4d via the deformation member 9a.

  Therefore, when the temperature of the plug holder 4 becomes higher than that of the cylinder head 3, the heat of the plug holder 4 moves only slightly to the cylinder head 3 via the deformable member 9a and the contact member 9b as shown in FIG. However, much heat is not transferred from the plug holder 4 to the cylinder head 3. Thus, the plug holder 4 can be suppressed from overcooling by the heat conducting member 9.

  When the engine load increases, the deformation member 9a is deformed at a temperature equal to or higher than the deformation temperature as shown in FIGS. The deformation member 9a lifts the contact member 9b with respect to the lower wall surface 4d. The upper surface of the contact member 9b is pressed against the upper wall surface 4c, and the contact area of the heat conducting member 9 with the plug holder 4 is increased. Thereby, the heat of the plug holder 4 is easily transmitted to the cylinder head 3 by the heat conducting member 9. Thus, the plug holder 4 is easily cooled by the heat conducting member 9.

  As described above, the sub-chamber gas engine 1 includes the piston 6 movably accommodated in the cylinder block 2 and the main combustion chamber 10 in cooperation with the piston 6 and the cylinder block 2 as shown in FIGS. It has the cylinder head 3 to divide, and the plug holder 4 which is inserted in the attachment hole 3c formed in the cylinder head 3 (subchamber type gas engine 1) and to which the spark plug 5 is attached. The plug holder 4 is formed with a sub chamber 11 to which fuel gas is supplied, and an injection hole 4 a that communicates the sub chamber 11 with the main combustion chamber 10. The mounting hole 3c of the cylinder head 3 (sub-chamber type gas engine 1) is provided with a heat conducting member 9 that can allow heat to move from the plug holder 4 to the cylinder head 3 (sub-chamber type gas engine 1). . The heat conducting member 9 includes a bimetal that deforms in response to heat, and has a portion where the contact area with the plug holder 4 increases as the temperature rises from the initial temperature to the deformation temperature.

  Therefore, the heat conducting member 9 has a small area (almost zero) in contact with the plug holder 4 when the temperature is low, such as when the engine is started. Therefore, it is difficult for the heat of the plug holder 4 to be transmitted to the cylinder head 3 (sub-chamber type gas engine 1), and the plug holder 4 can be suppressed from being overcooled by the heat conducting member 9. Thus, misfire in the sub chamber 11 in the plug holder 4 is reduced, and combustion in the sub chamber 11 is stabilized.

  On the other hand, the heat conducting member 9 has a larger area in contact with the plug holder 4 when the temperature at the time of high engine load is high. Thereby, the heat of the plug holder 4 is easily transmitted to the cylinder head 3 (sub-chamber type gas engine 1), and the plug holder 4 is easily cooled. Thus, it can be suppressed that the plug holder 4 becomes a heat source and the fuel gas in the main combustion chamber 10 is ignited early (preignition). Alternatively, it can be suppressed that the durability of the spark plug 5 is lowered and the durability is lowered, or that the efficiency of the intake into the sub chamber 11 is reduced due to the plug holder 4 becoming hot.

  As shown in FIG. 2, the heat conducting member 9 includes a deformable member 9a formed of bimetal, and a contact member 9b that is pressed by the deformable member 9a and has a large contact area with the plug holder 4. Therefore, the heat conducting member 9 can be formed at a lower cost than a configuration in which the whole is made of bimetal.

  As shown in FIGS. 2 and 3, the contact member 9 b has a C shape through which the plug holder 4 penetrates in the vertical direction. The deformation member 9a is installed below the contact member 9b. The plug holder 4 has an upper wall surface 4c that protrudes above the contact member 9b and against which the contact member 9b lifted by the deformation member 9a is pressed.

  Therefore, when the temperature of the contact member 9b is low, such as when the engine is started, the contact member 9b is separated from the upper wall surface 4c by using gravity, and the contact area with the plug holder 4 becomes small (almost zero). When the contact member 9b is lifted against the gravity by the deformable member 9a when the temperature at the time of high engine load is high, the contact member 9b is pressed against the upper wall surface 4c and the contact member 9b, the plug holder 4 and The contact area becomes larger. Therefore, since the heat conducting member 9 is a structure that uses gravity, it can be formed more easily than a structure that does not use gravity.

  The present invention is not limited to the above-described embodiment, and may be the following form. In another form, the sub chamber type gas engine 1 may have the 1st and 2nd heat conductive members 9c and 9d, as shown to FIGS. The first heat conducting member 9 c is installed in the first recess 4 e 1 formed in the plug holder 4. The second heat conducting member 9 d is installed in the second recess 4 e 2 formed in the plug holder 4.

  As shown in FIGS. 6 to 8, the first recess 4 e 1 is formed at a position farther from the sub chamber 11 than the tip of the spark plug 5. The second recess 4e2 is formed near the tip of the spark plug 5 or at a position closer to the sub chamber 11 than the tip. The heat conducting members 9c and 9d have deformation members 9a1 and 9a2 and contact members 9b1 and 9b2. The first deformation member 9a1 is formed of a bimetal that deforms according to the first deformation temperature. The second deformation member 9a2 is formed of a bimetal that is deformed at a second deformation temperature higher than the first deformation temperature.

  As shown in FIG. 6, the deformation members 9a1 and 9a2 are lower than a predetermined temperature (first deformation temperature or second deformation temperature) within a predetermined time from the start of the engine, and are not deformed or the deformation amount is small. The contact members 9b1 and 9b2 are separated from the upper wall surfaces 4c1 and 4c2 by gravity. Therefore, the heat of the plug holder 4 is hardly transmitted to the cylinder head 3, and the plug holder 4 can be suppressed from being overcooled by the heat conducting members 9c and 9d. Thus, misfire in the sub chamber 11 is reduced, and combustion in the sub chamber 11 is stabilized.

  As shown in FIG. 7, when the engine is under a low load, the first deformation member 9a1 becomes the first deformation temperature (for example, 200 ° C.) and deforms. The first contact member 9b1 comes into contact with the upper wall surface 4c1, and the region near the spark plug 5 of the plug holder 4 is cooled by the first heat conducting member 9c. As a result, the spark plug 5 is cooled, and a decrease in durability or melting damage of the spark plug 5 can be suppressed.

  On the other hand, the second deformation member 9a2 is not deformed even when the first deformation temperature is reached, and the second contact member 9b2 is separated from the upper wall surface 4c2. Therefore, the region near the sub chamber 11 of the plug holder 4 is hardly transmitted to the cylinder head 3 by the second heat conducting member 9d. Thereby, overcooling of the sub chamber 11 is suppressed, and misfire in the sub chamber 11 is reduced.

  As shown in FIG. 8, when the engine is heavily loaded, the second deformable member 9a2 is deformed at a second deformation temperature (for example, 250 to 700 ° C.). The second contact member 9b2 comes into contact with the upper wall surface 4c2, and the region near the sub chamber 11 of the plug holder 4 is cooled by the second heat conducting member 9d. Thereby, it can be suppressed that the plug holder 4 becomes a heat source and the fuel gas in the main combustion chamber 10 is ignited early.

  As described above, the mounting hole 3c is provided with the first and second heat conducting members 9c and 9d as shown in FIGS. The first heat conducting member 9c includes a bimetal that can be deformed at a temperature lower than that of the second heat conducting member 9d, and is farther from the main combustion chamber 10 than the second heat conducting member 9d and the spark plug 5 is inserted. It is installed at a position near the entrance of the mounting hole 3c.

  Therefore, as shown in FIG. 7, when the engine temperature rises, a first state occurs in which the first heat conducting member 9c is deformed and the second heat conducting member 9d is not deformed. In the first state, the vicinity of the spark plug 5 is cooled by the first heat conducting member 9c, and the region near the sub chamber 11 is hardly cooled by the second heat conducting member 9d. Thereby, durability of the spark plug 5 can be improved and overcooling of the sub chamber 11 can be suppressed.

  As shown in FIG. 8, when the temperature of the engine further rises, a second state (see FIG. 8) occurs in which both the first and second heat conducting members 9c, 9d are deformed. In the second state, the region near the sub chamber 11 is cooled by the second heat conducting member 9d. Thereby, it can be suppressed that the plug holder 4 becomes a heat source and the fuel gas in the main combustion chamber 10 is ignited early. Thus, the temperature of the plug holder 4 can be suitably adjusted according to the first state and the second state.

  In another embodiment, the sub-chamber gas engine 1 may have a heat conducting member 17 as shown in FIGS. The heat conducting member 17 is provided between the upper wall surface 4h formed on the plug holder 4 and the lower wall surface (head protruding portion 3d). The upper wall surface 4 h is formed above the heat conducting member 17.

  As shown in FIGS. 9 to 11, the heat conducting member 17 includes a deformable member 17 a, a mediating member 17 b, and a contact member 17 c. The mediating member 17b and the contact member 17c are formed of a material having a high thermal conductivity, for example, a metal. The mediating member 17b is installed on the gasket 14, and the contact member 17c is installed on the mediating member 17b. The mediating member 17b and the contact member 17c are O-shaped (annular), and the plug holder 4 is vertically penetrated.

  As shown in FIGS. 9 to 11, inclined portions 17b1 and 17c1 are formed on the mediating member 17b and the contact member 17c. The inclined portions 17b1 and 17c1 are formed in predetermined regions in the circumferential direction of the mediating member 17b and the contact member 17c, and face each other. When the deformable member 17a is deformed at the deformation temperature, the deformable member 17a pushes up the mediating member 17b. The contact member 17c is pushed upward by the mediating member 17b by the inclined portions 17b1 and 17c1, and is expanded in the radial direction.

  As a result, as shown in FIGS. 9 to 11, the contact member 17 c comes into contact with the constituent wall surface 3 e and the upper wall surface 4 h of the mounting hole 3 c, and the contact area between the heat conducting member 17 and the plug holder 4 increases. Part or all of the outer peripheral surface of the contact member 17c comes into contact with the constituent wall surface 3e of the mounting hole 3c, and the contact area between the heat conducting member 17 and the cylinder head 3 increases. Thus, heat of the plug holder 4 is easily transmitted to the cylinder head 3 by the heat conducting member 17.

  On the other hand, the heat conducting member 17 is separated from both the plug holder 4 and the cylinder head 3 when the engine is started as shown in FIG. Therefore, an air layer can be formed between the heat conducting member 17 and the plug holder 4 and between the heat conducting member 17 and the cylinder head 3. Therefore, the heat transfer from the plug holder 4 to the cylinder head 3 is reliably suppressed by the air layer, and the subcooling of the sub chamber 11 can be reliably suppressed.

  As described above, the cylinder head 3 has the head protruding portion 3d that protrudes from the constituent wall surface 3e of the mounting hole 3c toward the plug holder 4 and supports the heat conducting member 17 from below as shown in FIGS. . A heat conducting member 17 is installed between the head protrusion 3d and the upper wall surface 4h. Therefore, since the heat conducting member 17 is provided between the cylinder head 3 and the plug holder 4, it can be easily attached to the plug holder 4. For example, as shown in FIG. 2 and the like, it is not necessary to elastically deform the heat conducting member 9 in order to attach the heat conducting member 9 to the recess 4e formed on the outer periphery of the plug holder 4.

  In another embodiment, the sub-chamber gas engine 1 may have a heat conducting member 18 including a deformable member 18a and a contact member 18b shown in FIGS. The deformation member 18a is formed from bimetal. As shown in FIG. 14, the deformable member 18a is deformed radially outward when the deformable temperature is reached.

  As shown in FIGS. 12 to 14, the contact member 18 b has a C shape and is made of metal or the like. The contact member 18b is installed in the recess 4e. An inclined portion 18b1 facing the deformation member 18a is formed at the lower part of the inner peripheral surface of the contact member 18b. When the deformation member 18a reaches a deformation temperature and deforms radially outward, the contact member 18b is lifted by the inclined portion 18b1 and pushed radially outward. As a result, the upper surface of the contact member 18b comes into contact with the upper wall surface 4c, and a part or all of the outer peripheral surface of the contact member 18b comes into contact with the constituent wall surface 3e of the mounting hole 3c.

  As shown in FIGS. 12 to 14, the deformable member 18 a is deformed in a direction (radial direction) not related to gravity and pushes the contact member 18 b. As a result, the contact area between the contact member 18b and the cylinder head 3 and the contact area between the contact member 18b and the plug holder 4 are increased.

  In another form, the entire heat conducting member may be formed of bimetal. In another embodiment, the heat conducting member may integrally include a deformable member formed of bimetal and a contact member formed of metal or the like.

  In another embodiment, the heat conduction member may have a structure in which the contact area with the plug holder does not change by increasing from the initial temperature to the deformation temperature, but the contact area with the cylinder head increases. In another form, three or more heat conducting members may be provided in the attachment hole 3c.

  In another form, the gas engine 1 may have the cylinder block 2 and the cylinder head 3 integrally. In another form, the gas engine 1 may be used for another power source such as a ship or a gas heat pump. The plug holder 4 may be inserted into an attachment hole formed in the cylinder block 2.

DESCRIPTION OF SYMBOLS 1 ... Sub chamber type gas engine 2 ... Cylinder block 3 ... Cylinder head 3c ... Mounting hole 3d ... Head protrusion part 3e ... Constituent wall 4 ... Plug holder 4a ... Injection hole 4c, 4c1, 4c2, 4h ... Upper wall surface 4d, 4d1, 4d2 ... lower side wall surfaces 4e, 4e1, 4e2 ... concave portion 5 ... spark plug 6 ... pistons 9, 9c, 9d, 17, 18 ... heat conducting members 9a, 9a1, 9a2, 17a, 18a ... deformation members 9b, 9b1, 9b2, 17c, 18b ... contact member 9b3 ... hole 10 ... main combustion chamber 11 ... sub chamber 14 ... gasket 17b ... mediation member

Claims (5)

A sub-chamber gas engine,
Piston movably housed in a cylinder block, a cylinder head that defines a main combustion chamber in cooperation with the piston and the cylinder block, and an ignition hole inserted into a mounting hole formed in the sub-chamber gas engine A plug holder to which the plug is attached;
The plug holder is formed with a sub chamber to which fuel gas is supplied, and an injection hole communicating the sub chamber and the main combustion chamber,
Between the mounting hole and the plug holder, there is provided a heat conduction member capable of allowing heat to move from the plug holder to the sub-chamber gas engine,
The heat conduction member includes a bimetal that deforms in response to heat, and has a portion in which a contact area with at least one of the plug holder and the subchamber gas engine is increased by raising the deformation temperature. Gas engine. The sub-chamber gas engine according to claim 1,
The mounting hole is formed in the cylinder head,
The heat conducting member includes a deformable member formed of bimetal, and a sub-chamber type having a contact member that is pressed by the deformable member to increase a contact area with the plug holder and at least one of the cylinder head. Gas engine. A sub-chamber gas engine according to claim 2,
The contact member has a C shape or an O shape through which the plug holder penetrates in the vertical direction,
The deformation member is installed below the contact member,
The plug holder is a sub-chamber gas engine that has an upper wall surface that projects above the contact member and is pressed against the contact member lifted by the deformation member. A sub-chamber gas engine according to claim 3,
The cylinder head has a head protrusion that protrudes from the wall surface of the mounting hole toward the plug holder and can support the heat conducting member from below, and the cylinder head is interposed between the head protrusion and the upper wall surface. A sub-chamber gas engine with a heat conducting member. It is a subchamber type gas engine as described in any one of Claims 1-4,
The mounting hole is provided with first and second heat conducting members,
The first heat conducting member includes a bimetal that can be deformed at a lower temperature than the second heat conducting member, and is farther from the main combustion chamber than the second heat conducting member and the spark plug is inserted. A sub-chamber gas engine installed at a position close to the inlet of the mounting hole.

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