JP2013072346A - Reciprocating engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reciprocating engine capable of preventing outbreaks of adhesion and accumulation of carbon in a gas chamber even if an engine is operated for a long time and a high-pressure combustion gas is repeatedly led into the gas chamber, is repeatedly held therein, and is repeatedly discharged from the gas chamber.SOLUTION: In the reciprocating engine 1, a high-pressure combustion gas 12 over a piston is led into a gas chamber 4, which is surrounded by a top ring 5, a second ring 6 and a second land 7 of the piston 2 and an inner surface of a cylinder 8, from a gas passage 23, which is provided in an upper part 22 on a thrust side 10 of the inner surface 8 of the cylinder, in the initial time of an expansion stroke, so as to support the piston 2 from the thrust side 10. The piston 2 includes a partitioning means 37 which partitions a space between the top ring 5 and the second ring 6. A cleaning member 13 extending along the inside of the gas chamber 4 is inserted into the gas chamber 4 with a clearance 20 in the vertical direction freely to move in the vertical direction so as to clean the inside of the gas chamber 4 with the vertical movement of the cleaning member 13 by the clearance 20 with the reciprocating operation of the piston 2.

Description

  The present invention relates to an improvement in a reciprocating engine in which the piston is supported by high-pressure combustion gas (gas pressure float) against the side pressure acting on the piston in an explosion / expansion stroke, and the frictional resistance between the piston and the cylinder is reduced. .

  In the techniques described in these patent documents 1 to 4, a gas chamber is formed in the second land portion of the piston, and at the initial stage of the explosion / expansion stroke, the gas chamber is provided with a high pressure above the piston from a gas passage provided on the inner surface of the cylinder. In this technique, combustion gas is introduced and held, and the piston is supported from the thrust side by the introduced and held high-pressure combustion gas to reduce the frictional resistance between the piston and the inner surface of the cylinder.

International Publication No. 92/02722 International Publication No. 2004/079177 European Patent Application No. 1878901 International Publication No. 2008/047453

  However, during operation of the engine, introduction, retention, and discharge of high-pressure combustion gas above the piston are repeated in the gas chamber. Then, carbon deposits gradually accumulate on the surface of the gas chamber.

  Therefore, the present invention provides a reciprocating engine in which carbon adhesion and accumulation do not occur in the gas chamber even when the operation of the engine is performed for a long period of time and the introduction, maintenance, and discharge of the high-pressure combustion gas are repeated in the gas chamber. Is.

  The reciprocating engine of the present invention has a gas passage provided in a thrust side gas chamber surrounded by a piston top ring, a second ring, a second land, and a cylinder inner surface, at an upper portion of the cylinder inner surface at the initial stage of an expansion stroke. In the reciprocating engine in which the high-pressure combustion gas above the piston is introduced from above and the piston is supported from the thrust side by the introduced high-pressure combustion gas, the piston has a gas between the top ring and the second ring between the thrust side and the anti-thrust side. And a reciprocating motion of the piston. A cleaning member extending along the thrust gas chamber is inserted into the thrust gas chamber so as to be vertically movable with a gap in the vertical direction. The gas chamber is cleaned by moving the cleaning member up and down by the gap.

  According to the reciprocating engine of the present invention, the gas chamber on the thrust side surrounded by the piston top ring, the second ring, the second land, and the cylinder inner surface is provided in the upper part of the cylinder inner surface on the thrust side in the initial stage of the expansion stroke. In a reciprocating engine in which a high-pressure combustion gas above the piston is introduced from a gas passage and the piston is supported from the thrust side by the introduced high-pressure combustion gas, the piston has a thrust side and an anti-thrust side between the top ring and the second ring. And a cleaning member extending along the thrust-side gas chamber is inserted into the thrust-side gas chamber so as to be vertically movable with a gap in the vertical direction. The gas chamber is cleaned by moving the cleaning member up and down by the reciprocal movement of the gap. To have, engine operation for a long term, the introduction of high-pressure combustion gas to the gas chamber, holding, be repeated emissions, deposition of carbon into the gas chamber, the deposition is less likely to occur.

  In the reciprocating engine of the present invention, the top ring and the second ring are separated in the vertical direction on the thrust side rather than the anti-thrust side, and the cleaning member is widened in the vertical direction on the thrust side rather than both ends. It may be. According to such a reciprocating engine, the cleaning member can be more suitably moved in the vertical direction and the circumferential direction.

  The cleaning member may be formed of a metal plate having a thermal conductivity lower than that of the piston forming material (poor thermal conductivity), and has a heat resistance higher than the heat resistance of the piston forming material. And a metal plate having a heat resistance higher than the heat resistance of the piston forming material, even if it is formed from a metal plate having a heat conductivity lower than that of the piston forming material. It may be formed from.

  The said cleaning member may be formed from metal plates, such as a stainless plate and a stainless steel plate, for example.

  The top ring and the second ring may extend parallel to the piston top surface in the circumferential direction.

  The cleaning member may have an upper edge and a lower edge extending parallel to the piston top surface in the circumferential direction.

  The cleaning member may move up and down so as to sweep up and down the surface of the second land forming the gas chamber by reciprocating movement of the piston.

  In the reciprocating engine of the present invention, the “up and down direction” and the “up and down movement” are directions along the reciprocating direction of the piston and are movements.

  Even if the gas chamber is exposed to repeated introduction, maintenance, and discharge of high-pressure combustion gas, the cleaning member keeps moving up and down in the gas chamber to perform cleaning action. Does not occur.

FIG. 1 is a longitudinal sectional view of a reciprocating engine according to an example of an embodiment of the present invention. FIG. 2 is a longitudinal cross-sectional explanatory view showing the cleaning member in cross section in FIG. 1. FIG. 3 is a perspective explanatory view of the cleaning member shown in FIGS. 1 and 2. 4 is an explanatory view taken along the line IV-IV in the example shown in FIG.

  Embodiments of the present invention will be described below based on examples shown in the drawings. The present invention is not limited to these examples.

  1 and 2 show an initial state of the lowering process of the piston 2 in the explosion / expansion stroke.

  1 and 2 show the reciprocating engine 1 of the present embodiment in the early stage of the explosion / expansion stroke.

  2 is a piston, 3 is a cylinder. Reference numeral 4 denotes a gas chamber.

  The gas chamber 4 is formed by being surrounded by a top ring 5, a second ring 6, a second land 7, and a cylinder inner surface 8 of the piston 2.

  An arcuate cleaning member 13 extending along the gas chamber 4 is inserted into the gas chamber 4 so as to cover the second land 7 from the thrust side 10.

  The cleaning member 13 is inserted in the gas chamber 4 so as to be vertically movable with a gap 17 in the vertical direction (the reciprocating direction of the piston 2).

  Hereinafter, as shown in FIG. 3, the cleaning member 13 is formed in an arc shape in accordance with the circumferential surface of the second land 7. Further, the cleaning member has an upper edge 28 and a lower edge 29 extending in parallel to the piston top surface 18 in the circumferential direction.

  Further, the cleaning member 13 is formed so that the front and side surfaces thereof are matched to the shape of the gas chamber 4 and the vertical width 14 is uniform as a whole in the circumferential direction.

  Further, the cleaning member 13 has the vertical width 14 shorter than the vertical width 9 of the gas chamber 4 as a whole. This is because the gap 17 is formed in the vertical direction in a state where the cleaning member 13 is inserted into the gas chamber 4. The cleaning member 13 moves up and down in the gas chamber 4 by the distance of the gap 17.

  As shown in FIGS. 1 and 2, the cleaning member 13 is inserted into the gas chamber 4 with the front central portion 15 aligned with the thrust side 10.

  In particular, the cleaning member 13 moves up and down so as to sweep up and down the surface of the second land 7 forming the gas chamber 4 by reciprocation of the piston 2 during engine operation.

  Of course, the thickness t of the cleaning member 13 is such that the cleaning member 13 can freely move up and down (along the reciprocating direction of the piston 2) during operation of the engine within the gap 20 between the cylinder inner surface 8 and the surface 19 of the second land 7. That's it.

  The cleaning member 13 may be formed of a heat-resistant metal plate such as stainless steel or spring steel, but preferably has a thermal conductivity lower than the thermal conductivity of the material for forming the piston 2 (poor thermal conductivity). ) It may be formed from a metal plate, and is formed from a metal plate having a heat resistance higher than that of the material forming the piston 2 and a thermal conductivity lower than that of the material forming the piston 2. Even further, it may be formed of a metal plate having heat resistance higher than the heat resistance of the forming material of the piston 2. The cleaning member 13 can preferably prevent the adhesion and deposition of carbon on the inner and outer peripheral surfaces thereof. The cleaning member 13 has a C-ring shape.

  With respect to the piston 2 of the reciprocating engine 1 of the present embodiment, the top ring 5 and the second ring 6 that form the gas chamber 4 extend parallel to the piston top surface 18 in the circumferential direction of the piston 2.

  A plurality of gas passages 23 are provided in the upper portion 22 of the thrust side 10 of the cylinder inner surface 8. In the downward stroke of the piston 2, when the top ring 5 of the piston 2 passes over the gas passage 23, the combustion chamber 25 above the piston 2 and the gas chamber 4 of the piston 2 pass through the recess 24 of the gas passage 23. , And the high-pressure combustion gas 12 in the combustion chamber 25 is introduced into the gas chamber 4 and held.

  That is, when the top ring 5 of the piston 2 passes through the gas passage 23 at the upper part of the cylinder inner surface 8 in the initial stage of the explosion / expansion stroke, the combustion chamber 25 above the piston 2 and the gas chamber 4 of the piston 2 communicate with each other. The high-pressure combustion gas 12 is introduced and held in the gas chamber 4.

  At this time, the piston 2 tends to be pressed against the cylinder inner surface 8 against the thrust side 10 under the action of side pressure, but is supported from the thrust side 10 by the high-pressure combustion gas 12 introduced and held in the gas chamber 4 (piston 2 The descent process is lowered in a state of being opposed to the side pressure acting on the air.

  The reciprocating engine 1 may include a second ring 6 disposed in parallel to the top ring 5, and the piston 2 is provided between the top ring 5 and the second ring 6 and is half of the thrust side 10. A partition means 37 may be provided to partition the space 35 as an annular gas chamber and the space 36 as a semi-annular gas chamber on the anti-thrust side 11.

  According to the reciprocating engine 1 of the present embodiment as described above, the high pressure combustion gas 12 is introduced (inflow), held, and discharged into the gas chamber 4 of the piston 2 while the engine is operating, that is, while the piston 2 is reciprocating. Are repeatedly performed, and the cleaning member 13 continues to move up and down in the gas chamber 4 and the gas chamber 4 is constantly cleaned. For this reason, the gas chamber 4 is repeatedly introduced and held by the high-pressure combustion gas 12, but the cleaning action of the cleaning member 13 causes carbon to adhere and accumulate in the gas chamber 4, particularly on the surface 19 of the second land 7. Occurrence is prevented.

  The partition means 37 includes partition members 40 and 41 provided between the top ring 5 and the second ring 6, a spring 42 as a biasing member that elastically biases the partition member 40 toward the cylinder inner surface 8, and a partition A spring 43 as a biasing member that elastically biases the member 41 toward the cylinder inner surface 8, and is disposed between the top ring 5 and the second ring 6 on the side peripheral surface 6 b, and the cylinder inner surface 8. Space through a groove formed between the groove portions 44 and 45 that are concave toward the bottom surface and the bottom surface 54 that defines the ring groove 8a shown in FIG. 4 and the inner peripheral surface 55 of the second ring 6 that faces the bottom surface 54. The blocking members 56 and 57 disposed in the ring groove 8a and the blocking member 56 and 57 are disposed in the ring groove 8a and the blocking members 56 and 57 are secondly disposed so as to block the communication of the members 35 and 36 with each other. Coil springs 58 and 59 serving as pressing members that elastically press toward the inner peripheral surface 55 of the ring 6 and the bottom surface 54, and concave toward the inner peripheral surface 55 of the second ring 6. And concave portions (hole portions) 60 and 61. Each of the blocking members 56 and 57 is a cylindrical pin in this example. The partition member 40 is disposed in a space defined by the groove portion 44, and the partition member 41 is disposed in a space defined by the groove portion 45. The blocking member 56 and the coil spring 58 are disposed in a space defined by the concave portion 60, and the blocking member 57 and the coil spring 59 are disposed in a space defined by the concave portion 61. The partition members 40 and 41, the springs 42 and 43, the groove portions 44 and 45, the blocking members 56 and 57, the coil springs 58 and 59, and the concave portions 60 and 61 are each in the axial direction of the piston pin 4a. They are arranged facing each other. The partition member 40 and the blocking member 56 are arranged in a straight line in the reciprocating direction, and the partition member 41 and the blocking member 57 are arranged in a straight line with each other in the reciprocating direction. According to the partition means 37 described above, each of the blocking members 56 and 57 is disposed in the ring groove 8a and elastically pressed by the coil springs 58 and 59, respectively. In the stroke, the spaces 35 and 36 are prevented from communicating with each other via the ring groove 8a, and the partition members 40 and 41 are disposed between the top ring 5 and the second ring 6, respectively, and are separated by springs 42 and 43, respectively. By pressing each elastically, it is possible to prevent the spaces 35 and 36 from communicating with each other in each operation stroke of the reciprocating engine 1, and further, for example, the piston 3 is connected to the piston pin by gas pressure and inertial force. Even in the case of rotational movement in a plane orthogonal to the axial direction of 4a, a gap is generated between the blocking members 56 and 57 and the second ring 6. In addition to eliminating the gap between the partition members 40 and 41 and the cylinder inner surface 8, it is possible to maintain the gas pressure of the combustion gas introduced into the space 35 on the thrust side 10. it can.

DESCRIPTION OF SYMBOLS 1 Reciprocating engine 2 Piston 3 Cylinder 4 Gas chamber 5 Top ring 6 Second ring 7 Second land 8 Cylinder inner surface 9 Gas chamber vertical width 10 Thrust side 11 Anti-thrust side 12 High pressure combustion gas 13 Cleaning member 14 Cleaning member vertical width 15 Front center portion 16 Both side ends 17 Vertical gap 18 Piston top surface 19 Second land surface 20 Gap 22 Upper portion 23 Gas passage 24 Recess 25 Combustion chamber

Claims (4)

  The high-pressure combustion gas above the piston is introduced into the thrust-side gas chamber surrounded by the piston top ring, second ring, second land, and cylinder inner surface from the gas passage provided in the upper part of the cylinder inner surface on the thrust side at the initial stage of the expansion stroke. In the reciprocating engine which is introduced and supports the piston from the thrust side by the introduced high-pressure combustion gas, the piston has partition means for partitioning the space between the top ring and the second ring into gas chambers on the thrust side and the anti-thrust side. A cleaning member extending along the thrust side gas chamber is inserted into the thrust side gas chamber so as to freely move up and down with a gap in the vertical direction. A reciprocating engine that cleans the gas chamber by moving up and down.   The reciprocating engine according to claim 1, wherein the top ring and the second ring extend in parallel to the piston top surface in the circumferential direction.   The reciprocating engine according to claim 1 or 2, wherein the cleaning member has an upper edge and a lower edge extending in parallel in the circumferential direction with respect to the piston top surface.   The reciprocating engine according to any one of claims 1 to 3, wherein the cleaning member moves up and down so as to sweep up and down the surface of the second land forming the gas chamber by reciprocating movement of the piston.

Images