JPH07286525A - Reciprocating engine - Google Patents

Abstract

PURPOSE:To improve startability and reduce the occurrence of black smoke in, particularly, a diesel engine by forming a variable air chamber between a piston main body and a lid body which is supported by it in such a manner that the lid can come into contact with and be detached from it and blowing out a mixture in the variable air chamber forcedly into a combustion chamber in a compression process to generate swirl. CONSTITUTION:A recessed section 1a having diameter is formed in a crown section of a piston main body 1, and a small diameter section on a lower surface of a stepped lid body 4 which corresponds to the inner diameter of the piston main body 1 is fitted in the recessed section 1a in play to form a ring-like variable air chamber 12 between the lid body 4 and the crown section of the piston main body. A half-moon recessed section 5 for valve relief is formed on a top face of the lid body 4, and inclined slits 6... are formed on the peripheral surface. Two support rods 7 each on the right and left, four rods in total, are provided vertically in a lower part of the lid body 4 and floatingly supported on springs 9, 10. The mixture in the variable air chamber 12 whose volume is reduced in the compression stroke is blown out through the slits 6... to generate swirl in a combustion chamber 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating engine in which a piston reciprocates to generate swirl in a combustion chamber during a compression process.

[0002]

2. Description of the Related Art As one of the methods for increasing combustion efficiency, it is known that it is effective to generate a forced vortex in a combustion chamber. Conventionally, as a technique therefor, for example, as shown in FIG. 7, an inlet port 19 for air or fuel is provided in the cylinder 1
4 (disclosed in Japanese Patent Laid-Open No. 52-37610) or a technique in which a spiral groove 20 is formed on the upper surface of the piston P as shown in FIG. 8 ( (Disclosed in Japanese Utility Model Laid-Open No. 53-19610) is known.

[0003]

Since the former technique has a unique configuration in which the port is provided on the side surface of the cylinder, it is formed in a special reciprocating engine in which a pair of pistons are opposed to one combustion chamber. Is relatively easy, but it is difficult to apply due to its structure in a general reciprocating engine having a cylinder head. Both the latter and the former generate a swirl flow in the suction process, and even if one expects the maximum swirl to occur in the compression process that requires the swirl most, the swirling motion is actually The effects of weakening and increasing fuel evaporation, diffusion, and flame propagation speed are far below expected levels.

[0004]

SUMMARY OF THE INVENTION The present invention is a reciprocating engine for generating swirl during a compression process, and its gist is to attach and detach a lid body to and from a pressure surface of a piston body. To form a variable air chamber between the piston body and the lid, and to form a ventilation path in the variable air chamber that opens in the pressurizing direction. A lid body in which a concave portion having a diameter smaller than the diameter of the main body is formed in a concentric circle, and a disk shape of two steps, large and small, which is equal to the diameter of the piston main body and the diameter of the concave portion, and a slit penetrating in the front-back direction around the large diameter portion is formed. Is floatingly supported with respect to the piston body such that a small diameter portion of the lid body is slidable in the recess of the piston body, and the lid body is lifted up in the intake process so that the lid body, the piston body and the cylinder are Introduce the air-fuel mixture into the enclosed variable air chamber, press the lid against the piston main body side in the compression process, and blow out the air-fuel mixture in the variable air chamber introduced in the intake process into the combustion chamber through the slit. Due to
The swirl is generated in the combustion chamber. Further, it is desirable that the slits are inclined in the same direction so that swirl flow is easily generated.

[0005]

The swirl is generated in the combustion chamber during the compression process, and the swirl is forcibly caused by the jetting air-fuel mixture, so that it is extremely powerful. As a result, the fuel evaporates quickly and diffuses uniformly, and it is expected that the flame propagation speed after ignition and the fuel consumption rate will improve. Further, it is possible to deal with the problem by simply modifying the piston without modifying the cylinder head, and even with an existing engine, the same effect can be obtained by replacing the piston.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a reciprocating engine according to the present invention will be described with reference to the drawings. FIG. 1 shows a piston of a reciprocating engine, and FIG. 2 shows an AA line cut portion of the piston. A recess 1a having a diameter smaller than the diameter is formed in the crown portion of the piston main body 1 and is formed downward. Cavity S
It has a partition wall 1b at the boundary with. Through holes 1c, 1c for inserting piston pins are formed in the front and rear surfaces of the peripheral wall of the lower cavity S, and the piston pin 2 is horizontally installed by inserting both ends into the through holes 1c, 1c. . Piston rings 3, 3, 3 are fitted around the outer circumference of the piston body 1 by utilizing ring grooves.

Reference numeral 4 denotes a lid body formed in a large and small two-stage disc shape corresponding to the diameter of the piston body 1 and the diameter of the recess 1a, and the upper portion of the large diameter has a half-moon recess 5 for releasing the valve on the upper surface.
And the inclined slits 6, 6
・ Is cut. Also, on the lower surface of the small diameter lower part,
A total of four support rods, two each on the left and right, are suspended.

The piston body 1 has support rods 7, 7 ... Hanging on the left and right sides of the partition wall 1b.
Are provided with rod insertion holes 8, 8 ...
The supporting rods 7, 7 ...
The small diameter lower part of the lid body 4 is fitted into the concave portion 1a of the piston body 1 by inserting. On the other hand, on the support rods 7, 7, ..., Coil springs 9, 10 are provided between the lid 4 and the partition wall 1b and in the portions projecting downward from the partition wall 1b, respectively.
By externally fitting and attaching the retainer member 11 to the tip, the lid 4 is supported in a floating manner. Between the piston body 1 and the lid body 4 which is floatingly supported by the piston body 1, when accommodated in a cylinder, it is surrounded by the cylinder, and a ring-shaped variable volume whose volume changes as the lid body 4 moves up and down. An air chamber 12 is formed (see FIGS. 3 and 4).

The piston formed in this manner is used in the cylinder 1 so that the combustion chamber 13 is formed in the upper portion as shown in FIG.
In the reciprocating engine installed in 4, the intake valve 1
In the intake process in which 5 is opened, the lid body 4 is pulled by the piston body 1 that rapidly descends, and the lid body 4 is temporarily lifted from the piston body 1 and the variable air chamber 12 expands. With the expansion of the variable air chamber 12, the combustion chamber 12
The air-fuel mixture therein is introduced into the variable air chamber 12 through the slits 6, 6. Further, in the compression process in which the intake valve 15 is closed, as shown in FIG.
Pushes lid 4 up, so to speak, lid 4 is piston body 1
Since the variable air chamber 12 is contracted to the side and the variable air chamber 12 is reduced, the air-fuel mixture in the variable air chamber 12 is slit 6,6.
.. is blown out vigorously, whereby the air-fuel mixture in the combustion chamber 13 is swirled and compressed, and a powerful swirl is generated.

In this embodiment, since the valve-releasing meniscus recess is formed on the upper surface of the lid and the slit which is the air passage is inclined, the generation of vortex flow is promoted and the swirl effect is doubled. It Note that the lid contacting / separating operation is not only related to the inertial force due to the up-and-down motion of the piston, but is also delicately related to the strength of the coil spring, the pressure change in the combustion chamber, and so on. Careful consideration must be given to their interaction for optimality.

In the above embodiment, the air-fuel mixture in the ring-shaped variable air chamber is blown out from the slits. However, as illustrated in FIG. 5, the inclined slits 6, 6 as ventilation passages are formed on the upper peripheral edge of the piston body 1. A rising wall 16 having is provided, and a lid body 4 floatingly supported by a single supporting rod 7 and coil springs 9 and 10 hanging downward from the opening upper surface of the recess surrounded by the rising wall 16. With the cover structure, a wide variable air chamber 12 can be secured, and for example, a cam surface 17a is formed on the connecting rod 17, and the cam surface 17a is maintained while the piston rises from the bottom dead center to a certain height. It is also possible to press the lower end of the support rod 7 in pressure and forcibly control the timing and speed at which the lid 4 is pushed down. Further, as illustrated in FIG. 6, the piston body 1 is covered up to its peripheral surface with a lid body 4, and piston rings 3, 3, ... Are fitted around the lid body 4, while the piston body 1 is placed inside the lid body 4. , The coil springs 9 and 10 are slidably supported in a floating state, and the lid body 4 is provided with upward radial through holes 18 which are twisted as a ventilation passage, and the variable air chamber 12 is provided.
If the air-fuel mixture inside has a structure that blows out in a spiral shape, it is possible to generate swirls that spread radially from the center,
Since the sliding surface between the piston body and the lid is exposed inside the crankcase, oil is also supplied to that portion, and the problem of poor lubrication is solved. In the present invention, the structure for supporting the lid body so that it can be contacted and separated from the pressure surface side of the piston body is
The structure not only allows the lid body to move parallel to the piston, but also allows the lid body to rotate about one end as a fulcrum, and the other end side to move in and out.

[0012]

According to the present invention, the air-fuel mixture in the variable air chamber is forcibly blown into the combustion chamber during the compression process, and swirl is generated by the blown air-fuel mixture. Very close to the ideal,
The mixture of air and fuel is promoted and the mixture is diffused throughout the combustion chamber. Therefore, in combination with the improvement of the propagation speed of the combustion flame, particularly in the diesel engine, remarkable effects such as improvement of startability, reduction of diesel black smoke, and improvement of output and fuel consumption rate appear.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a piston of a reciprocating engine according to the present invention.

FIG. 2 is a cross-sectional explanatory view of a section cut along the line AA in FIG.

FIG. 3 is an explanatory diagram of an inhalation process.

FIG. 4 is an explanatory diagram of a compression process.

FIG. 5 is an explanatory diagram of a modification example.

FIG. 6 is a plan view of a modified example and a cross-sectional explanatory view thereof.

FIG. 7 is an explanatory diagram of a conventional example.

FIG. 8 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1 ... Piston body, 1a ... Recess, 1b ... Partition wall, 1c ... Through hole, 2 ... Piston pin, 3 ... Piston ring, 4 ... Lid, 5 ... Half moon recess, 6 ... Inclined slit, 7 ... Support rod, 8 ... Rod insertion hole, 9,
10 ... Coil spring, 11 ... Retainer member, 1
2 ... Variable air chamber, 13 ... Combustion chamber, 14 ... Cylinder, 15 ... Intake valve, 16 ... Standing wall, 17
..Connecting rods, 17b..Cam surfaces, 18.
・ Through hole, 19 ・ ・ Introduction port, 20 ・ ・ Spiral groove, P ・ ・ Piston, S ・ ・ Lower cavity.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F02F 3/00 301 Z

Claims (3)

[Claims] 1. A variable air chamber is formed between a piston body and a lid body by supporting a lid body on the pressure surface side of the piston body so that the lid body can be brought into contact with and separated from the pressurized surface. In the intake process, the lid is separated to introduce the air-fuel mixture in the combustion chamber into the variable air chamber, and in the compression process, the lid is pressed against the piston main body side. A reciprocating engine, wherein swirl is generated in a combustion chamber by blowing air-fuel mixture introduced in an intake process into a combustion chamber from a ventilation passage. 2. A reciprocating piston main body is provided with a recess having a diameter smaller than the diameter of the piston main body in a crown portion, and has a large and small two-step disc shape corresponding to the diameter of the piston and the diameter of the recess.
A lid body having a slit that penetrates in the front-back direction around the large diameter portion is floatingly supported with respect to the piston body so that the small diameter portion of the lid body is slidable in the recess of the piston. In the process, the lid is lifted up and the air-fuel mixture is introduced into the variable air chamber surrounded by the lid, the piston body and the cylinder.In the compression process, the lid is pressed against the piston body side and introduced in the intake process. A reciprocating engine, wherein swirl is generated in the combustion chamber by blowing air-fuel mixture in the variable air chamber into the combustion chamber through a slit. 3. The reciprocating engine according to claim 2, wherein the slits are inclined in the same direction.