JP2004132322A - Reciprocating engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reciprocating engine which can reduce more effectively the sliding friction resistance between a piston and the inner surface of a cylinder. <P>SOLUTION: The four-cycle reciprocating engine 1 includes the cylinder 2, the piston 3 which reciprocates within the cylinder 2, a connecting rod 5 which is rotatably connected to the piston 3 via a piston pin 4 at its small end portion, and a crankshaft 21 which is rotatably connected to a large end 20 of the connecting rod 5. Further, the engine 1 includes piston rings 9 and 10 which are arranged adjacently to each other in the reciprocating direction of the piston 3 and which are respectively fitted in a pair of ring grooves formed on the side peripheral surface 6 of the piston 3, a partition means 14 which divides an annular space between the piston rings 9 and 10 into a semi-annular space 12 on the thrust side and a semi-annular space 13 on the anti-thrust side, and a communication means 16 for communicating the space 12 with a combustion chamber 15 where gaseous mixture of fuel and air is burnt. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a reciprocating engine.
[0002]
[Prior art]
In a reciprocating engine, in order to reduce sliding friction resistance between the cylinder and the piston, a gas chamber for guiding and storing combustion gas from the combustion chamber is provided between the inner surface of the cylinder and the side surface of the piston facing the inner surface. The piston is lifted from the inner surface of the cylinder by the gas pressure of the combustion gas in the gas chamber against the side pressure applied to the piston in the thrust direction during the combustion stroke, and the inner surface of the cylinder is reciprocated by the piston. A technique has been proposed to reduce the sliding frictional resistance between the piston and the side of the piston. One example of the proposed reciprocating engine includes a first piston ring disposed adjacent a piston upper surface that defines a combustion chamber in which a mixture of fuel and air burns, and a first piston ring adjacent the first piston ring. When the piston is located near the top dead center, the annular space between the second piston ring and the semi-annular space on the thrust side and the semi-annular space on the non-thrust side are divided. In some cases, a gas passage is formed in a side wall of a cylinder for connecting a thrust-side semi-annular space to a combustion chamber.
[0003]
[Patent Document 1]
JP-A-5-26106
[Problems to be solved by the invention]
By the way, in a general reciprocating engine, the rotational axis of the crankshaft is not eccentric with respect to the center line of the cylinder bore. Is difficult to obtain to the extent that is sufficiently satisfactory.
[0005]
The present invention has been made in view of the above points, and an object of the present invention is to provide a reciprocating engine that can more effectively reduce the reciprocating resistance of a piston with respect to a cylinder.
[0006]
[Means for Solving the Problems]
A reciprocating engine according to a first aspect of the present invention is a reciprocating engine in which a rotation center of a crankshaft is offset to a thrust side with respect to a center line of a cylinder bore, and is disposed adjacent to each other in a reciprocating direction of a piston. The first and second piston rings respectively fitted in the first and second ring grooves formed on the side surface of the piston, and the space between the first and second piston rings, the thrust side And a communicating means for communicating the thrust-side space with the combustion chamber.
[0007]
According to the reciprocating engine of the first aspect of the present invention, the effect of the offset and the effect of the introduction of the combustion gas into the thrust space can more effectively reduce the reciprocating resistance of the piston with respect to the cylinder. Can be.
[0008]
In the reciprocating engine according to the second aspect of the present invention, in the reciprocating engine according to the first aspect of the present invention, the communication means includes one or more communication paths provided on an inner surface of the cylinder. Alternatively, the thrust-side space communicates with the combustion chamber via a plurality of communication passages.
[0009]
One or more communication passages may be provided as described above.In the case of a plurality of communication passages, the combustion gas in the combustion chamber is communicated with the combustion chamber by communicating the thrust-side space with the combustion chamber through the plurality of communication passages. It can be more quickly and sufficiently introduced into the space.
[0010]
In the reciprocating engine according to the third aspect of the present invention, in the reciprocating engine according to the first or second aspect of the present invention, when the piston is located near the top dead center, the communication means fills the space on the thrust side. It is designed to communicate with the combustion chamber.
[0011]
In addition, the reciprocating engine in any of the first to third aspects of the present invention may be a four-cycle engine, a two-cycle engine, or a diesel engine, and any of the engines suitably exerts the effects of the present invention. obtain. Further, in the present invention, the communication path may be in any form such as a through hole, a groove, or a recess.
[0012]
Next, embodiments of the present invention will be described in more detail based on preferred examples shown in the drawings. The present invention is not limited to these examples.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 3, a four-cycle reciprocating engine (four-cycle gasoline engine) 1 according to the present embodiment includes a cylinder 2, a piston 3 reciprocating in the cylinder 2, and a piston 3 at a small end through a piston pin 4. 3, a connecting rod 5 rotatably connected to the connecting rod 5, a crankshaft 21 rotatably connected to the large end 20 of the connecting rod 5, and a crankshaft 21 disposed adjacent to each other in the reciprocating direction of the piston 3. The piston rings 9 and 10 respectively fitted in a pair of ring grooves formed in the side peripheral surface 6 of the piston 3 and the annular space between the piston rings 9 and 10 are divided into thrust side semi-annular spaces 12 and A partitioning means 14 for partitioning into a semi-annular space 13 on the opposite thrust side, and a communicating means 16 for communicating the space 12 with a combustion chamber 15 in which a mixture of fuel and air is burned are provided.
[0014]
The cylinder 2 has a cylinder bore (space) 18 defined by an inner surface 17 thereof, and the piston 3 is arranged in the cylinder bore 18 so as to be able to reciprocate. The cylinder 2 is provided with an intake valve 2a and an exhaust valve 2b.
[0015]
The piston 3 is provided with an oil ring 19 on the side peripheral surface 6 in this example.
[0016]
The rotation center C of the crankshaft 21 is offset to the thrust side with respect to the center line D of the cylinder bore 18. In this example, as shown in FIG. 2, the rotation center C is applied to the air-fuel mixture in the combustion chamber 15 before the piston 3 passes through the top dead center and is located near the top dead center. When the ignition is performed, the line connecting the rotation center E of the connecting rod 5 with respect to the piston pin 4 and the rotation center F of the connecting rod 5 with respect to the crankshaft 21 is inclined so as to be inclined to the anti-thrust side with respect to the center line D. And, as shown in FIG. 3, after the piston 3 has passed through the top dead center and the gas pressure in the combustion chamber 15 has increased to the maximum while being located near the top dead center, It is eccentric toward the thrust side with respect to the center line D such that the line connecting the center of rotation E and the center of rotation F extends in the same direction as the direction in which the center line D extends. The offset width of the rotation center C with respect to the center line D is preferably in the range of 11 mm to 13 mm, and more preferably in the range of 12 mm to 12.5 mm, but is not limited thereto.
[0017]
The piston ring (top ring or gas ring) 9 is arranged adjacent to the head end surface 23 of the piston 3. Preferably, the piston ring 9 is disposed such that its abutment is located closer to the space 12 than the partition member 40 is. The piston ring 9 has an outer peripheral surface abutting against an inner surface 17 with elastic force.
[0018]
The piston ring (second ring or gas ring) 10 is arranged on the side peripheral surface 6 with the piston ring 9 interposed between the piston ring 9 and the head end surface 23. Preferably, the piston ring 10 is disposed such that its abutment is located closer to the space 13 than the partition member 40 is. The piston ring 10 is in elastic contact with the inner surface 17 on the outer peripheral surface.
[0019]
The partitioning means 14 includes a pair of partition members 40 provided between the piston rings 9 and 10 and arranged to face each other in the axial direction of the piston pin 4.
[0020]
The communication means 16 includes a communication passage 70 provided on the inner surface 17 on the thrust side of the cylinder 2. When the piston 3 is located near the top dead center, the communication passage 70 divides the space 12 into the combustion chamber 15. It is arranged to communicate with. In this example, the communication passage 70 is defined by a concave surface 71 formed on the inner surface 17 of the cylinder 2.
[0021]
According to the communication means 16, when the piston 3 is located near the top dead center, the space 12 is communicated with the combustion chamber 15 by the communication passage 70, so that the combustion gas in the combustion chamber 15 is introduced. Therefore, a counter pressure B in the anti-thrust direction against the pressure A in the thrust direction applied to the piston 3 in the combustion stroke can be applied to the piston 3, and the piston 3 Can be gas floated.
[0022]
The operation of the reciprocating engine 1 according to the present embodiment will be described below. In the combustion stroke of the mixture of fuel and air started after the end of the compression stroke, as shown in FIG. Before passing and while being located near the top dead center, the air-fuel mixture in the combustion chamber 15 is ignited, and the thrust-side space 12 is communicated with the combustion chamber 15 through the communication passage 70 to form the thrust-side space 12. The combustion gas was introduced, and as shown in FIG. 3, the gas pressure of the combustion gas was maximized and increased after the piston 3 passed the top dead center of the piston 3 and was located near the top dead center. When the piston 3 receives the gas pressure, it accelerates toward the bottom dead center.
[0023]
According to the reciprocating engine 1 of the present embodiment, the rotation center C of the crankshaft 21 is offset to the thrust side with respect to the center line D of the cylinder bore 18, so that in the present embodiment, the piston 3 is When the gas pressure of the combustion gas has increased to a maximum after passing through the top dead center and in the vicinity of the top dead center, the line connecting the rotation centers C and F extends in the direction in which the center line D extends. Therefore, the side pressure A in the thrust direction applied to the piston 3 based on the gas pressure in the combustion chamber 15 is greatly reduced, and the space 12 is sufficiently expanded against the side pressure A. As a result of applying the opposite pressure B toward the anti-thrust side to the piston 3 by the gas pressure of the introduced combustion gas, the piston 3 can be appropriately floated. As a result, the reciprocating engine 1 of this example has To During combustion stroke, it is possible to significantly reduce the sliding frictional resistance in the thrust side between the piston rings 9 and 10 and the inner surface 17 of the cylinder 2 that occurs on the basis of the side pressure A.
[0024]
【The invention's effect】
According to the present invention, it is possible to provide a reciprocating engine capable of more effectively reducing the reciprocating resistance of the piston with respect to the cylinder.
[Brief description of the drawings]
FIG. 1 is an explanatory front view of an example of an embodiment of the present invention.
FIG. 2 is an operation explanatory diagram of the example shown in FIG. 1;
FIG. 3 is an operation explanatory diagram of the example shown in FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reciprocating engine 2 Cylinder 3 Piston 4 Piston pin 5 Connecting rod 6 Side peripheral surface 9, 10 Piston ring 12, 13 Space 14 Partitioning means 15 Combustion chamber 16 Communication means 18 Cylinder bore 20 Large end 21 Crankshaft

Claims (3)

A reciprocating engine in which a rotation center of a crankshaft is offset to a thrust side with respect to a center line of a cylinder bore, the reciprocating engines being arranged adjacent to each other in a reciprocating direction of a piston, and formed on a side surface of the piston. First and second piston rings fitted in the first and second ring grooves, and a partitioning means for partitioning a space between the first and second piston rings into a thrust-side space and a non-thrust-side space And a communicating means for communicating a thrust side space with the combustion chamber. The communication means includes one or a plurality of communication passages provided on an inner surface of the cylinder, and communicates a thrust-side space to the combustion chamber through the one or a plurality of communication passages. The reciprocating engine described in 1. The reciprocating engine according to claim 1 or 2, wherein the communicating means communicates the thrust side space with the combustion chamber when the piston is located near the top dead center.

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