JPH03213646A - Cylinder sealing device - Google Patents

Abstract

PURPOSE:To improve the sealing effect by making a permanent magnet provided to a piston attract a seal ring which consists of a magnetic fluid, and holding the magnetic fluid strongly with the magnetic force of both the permanent magnet and a fixed electromagnet in a necessary time, while cooling the magnets to secure their magnetisms. CONSTITUTION:On the outer circumferential surface of a piston 2, a compression ring 22 and a permanent magnet 3 opposing to a cylinder liner 11 are provided respectively. And, between the both magnetic poles 32 and 33 of the permanent magnet 3 and the cylinder liner 11, a seal ring 5 is placed to form a passage of magnetic flux to act between the both magnetic poles 32 and 33, and the both fixed magnetic poles 45 and 46 of a core 43. And when the piston 3 reaches near the top dead center, the magnetic flux of a closed circuit is generated along a line of magnetic induction between the permanent magnet 3 and the core 43, and the seal ring 5 is divided into the upper and the lower parts. As a result, a low pressure and low temperature of combustion gas leaked through the compression ring 22 is sealed with the seal ring 5. In this case, the core 43 is cooled by the cooling water flowing through a pipe line 13.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a cylinder seal device that seals a cylinder liner and an outer peripheral surface of a piston using a magnetic fluid.

(Prior Art) In a conventional engine, sealing between a cylinder liner and an outer peripheral surface of a piston is achieved by a plurality of piston rings.

The piston ring is an annular ring with a portion of its circumference cut away, and the diameter of the outer circumferential portion of the circular tube is larger than the inner diameter of the cylinder by a predetermined amount.

The inner diameter portion of the piston ring is placed into a groove carved on the outer peripheral surface of the piston, and the piston ring is inserted into the cylinder. Then, the piston ring expands and presses against the cylinder liner.

Therefore, the piston ring isolates the inside of the combustion chamber from the outside of the crankcase.

(Problem to be Solved by the Invention) Such a conventional piston ring that seals the cylinder liner and the outer circumferential surface of the piston is designed to prevent hydrocarbons and unburned substances in the combustion chamber from entering the notch or abutment of the piston ring. The gas becomes blow-by gas and leaks outside, causing air pollution.

Additionally, the lubricating oil inside the crankcase enters the combustion chamber through the joint, increasing the amount of lubricating oil consumed, and when the lubricating oil is burned, white smoke is emitted along with the exhaust gas. .

The present invention has been made in view of the above-mentioned points, and provides a perfect seal between the cylinder liner and the outer peripheral surface of the piston, completely preventing blow-by gas from leaking from the combustion chamber and lubricating oil from entering the combustion chamber. It is an object of the present invention to provide a cylinder seal device that can prevent the above.

(Means for Solving the Problems) According to the present invention, a piston whose head end face is covered with a heat insulating layer, a permanent magnet having an annular movable magnetic pole disposed around the outer peripheral surface of the piston, and an electromagnet having a fixed magnetic pole facing the movable magnetic pole at a position near the top dead center of the piston, a cooling device for cooling the electromagnet with a working fluid, and energizing the electromagnet when the movable magnetic pole and the fixed magnetic pole face each other. an energization control means that forms a closed circuit of magnetic flux between the two magnetic poles; and a energization control means that is continuously interposed on the entire circumference between the movable magnetic pole and the inner surface of the cylinder liner, and when the electromagnet is energized, a closed circuit of the magnetic flux. It is possible to provide a cylinder seal device characterized in that it has a sealing ring made of magnetic fluid that forms a part of the movable magnetic pole and forms a path for magnetic flux passing through the movable magnetic pole when not energized.

(Function) In the cylinder seal device of the present invention, a permanent magnet is provided around the outer periphery of the piston, and the permanent magnet attracts a sealing ring made of magnetic fluid to seal the combustion chamber. In addition, particularly when the pressure in the combustion chamber is high near top dead center, the magnetic force of both the permanent magnet and the fixed electromagnet strongly holds the magnetic fluid and seals the combustion chamber.

Furthermore, since the permanent magnet and fixed electromagnet are insulated from the combustion heat generated within the combustion chamber, the magnetic force does not decrease.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of the engine according to this embodiment.

1 is a cylinder, and a cylinder liner 11 is fitted into the inner peripheral surface of the cylinder 1. The cylinder liner 11
is made of a non-magnetic ceramic such as silicon nitride, and the inner peripheral surface is plated with chromium (Cr).

Therefore, the inner circumferential surface of the cylinder liner 11 has excellent wear resistance and a small coefficient of friction.

By the way, the cylinder liner 11 is a non-magnetic material and may be formed of a metal material as long as it satisfies conditions such as predetermined strength.

The outer peripheral part of the cylinder liner 11 is a cylinder block 12.
covered with.

Note that the upper outer periphery of the cylinder liner 11 and the cylinder block 12 are not in contact with each other, and a pipe line 13 is provided on the outer periphery of the cylinder liner 11.

Engine cooling fluid, such as water or oil, circulates through the pipe 13.

A heat insulating gasket 1 is attached to the upper end surface of the cylinder liner 11.
4, and is insulated from the headliner 15 covering the inner peripheral surface of the cylinder head.

A piston 2 is made of a non-magnetic material such as an aluminum alloy, and is slidably held within the cylinder 1. The end face of the head portion of the piston 2 is covered with a heat insulating layer 21 made of ceramic or the like having excellent heat resistance to prevent heat generated within the combustion chamber from being transmitted to the piston 2.

A compression ring 22 is disposed on the outer peripheral surface of the piston 2 at a predetermined distance from the heat insulating layer 21 . The compression ring 22 is similar to a conventional piston ring.

A cylinder liner 11 is further provided on the outer peripheral surface of the piston 2.
An annular permanent magnet 3 having magnetic poles facing each other is provided around the periphery. An annular separator 31 made of a non-magnetic material is arranged between both magnetic poles of the permanent magnet 3.

4 is a combustion chamber formed by the cylinder liner 11, headliner 15, and heat insulating layer 21;
An intake valve 41 and an exhaust pulp 42 are provided.

Inside the pipe line 13, there is an annular core 43 made of a magnetic material.
It is fitted onto the outer peripheral surface of the cylinder liner 11. Further, an excitation coil 44 for exciting the core 43 is wound around the core 43.

Note that when the cooling fluid circulating in the pipe line 13 is water, the excitation coil 44 is sufficiently insulated from the water.

Reference numeral 6 denotes a rotary shaft that is rotationally driven by the piston 2, and a rotation sensor 61 that detects the rotational speed of the rotary shaft 6 is installed near the outer circumference of the rotary shaft 6, and a rotation sensor 61 that detects the rotational speed of the rotary shaft 6. A position sensor 62 for detecting the operating position of the piston 2 is provided.

The rotation sensor 61 and the position sensor 62 are connected to the controller 7.
The controller 7 is connected to the controller 7, and a detection signal is input to the controller 7. Further, the excitation coil 44 is connected to the controller 7 and receives power from the controller 7.

In addition to an input/output interface that controls the input/output of signals with the rotation sensor 61, position sensor 62, and excitation coil 44, the chondral rough has a ROM that stores programs in advance, and performs calculations based on the programs stored in the ROM. The controller 7 is composed of a CPU that performs the calculation, a RAM that temporarily stores calculation results and various data, a control memory that controls the flow of signals inside the controller 7, and the like.

Details of the magnetic pole portion of the permanent magnet will be explained using FIG. 2.

FIG. 2 is an enlarged view of the permanent magnet 3.

In addition, this figure shows the case where the piston 2 is at the top dead center position,
Further, the same numbers as in FIG. 1 above indicate the same members.

Both 32 and 33 are magnetic poles of the permanent magnet 3, and in this embodiment, the magnetic pole 32 is excited to the north pole, and the magnetic pole 33 is excited to the south pole.

Moreover, both the magnetic pole 32 and the magnetic pole 33 are connected to the cylinder liner 1.
The magnetic pole 32 facing the inner peripheral surface of the combustion chamber 1 is longer than the magnetic pole 33 in the sliding direction of the piston 2, that is, in the vertical direction in this figure. There is.

Both 45 and 46 are fixed magnetic poles of the core 43, and when power is supplied from the controller 7 to the excitation coil 44, the fixed magnetic pole 45 is excited to the S pole and the fixed magnetic pole 46 is excited to the N pole.

Therefore, a closed circuit of magnetic flux is formed by the magnetic poles 32 and 33 of the permanent magnet 3 and the fixed magnetic poles 45 and 46.

Further, the length of the fixed magnetic pole 46 in the vertical direction is longer than the length of the fixed magnetic pole 45 in the vertical direction.

With the above configuration, the opposing state between the magnetic pole 32 and the fixed magnetic pole 45, and between the magnetic pole 33 and the fixed magnetic pole 46, continues for a predetermined crank angle, for example, ±40'', around the top dead center and the top dead center.

A sealing ring 5 is made of magnetic fluid and isolates the combustion chamber 4 from the outside.

The magnetic fluid forming the ring seal 5 is made by modifying the surface of ferrite particles with a particle size of several hundred angstroms with an organic fatty acid so that they do not separate in a dispersion medium such as diester. It is a fluid. Since the ferrite fine particles are stably dispersed in the dispersion medium, the fluid itself appears to have magnetic properties.

Therefore, the sealing ring 5 is interposed between the magnetic poles 32 and 33 and the cylinder liner 11, and serves as a path for magnetic flux acting between the magnetic poles 32 and 33 and the fixed magnetic poles 45 and 46.

Next, the operation of this embodiment with the above configuration will be explained.

When the piston 2 is not within the predetermined crank angle centered on the top dead center, that is, when the magnetic poles 32 and 33 are not opposed to the fixed magnetic poles 45 and 46, the sealing ring 5 is located at the magnetic pole. 32 and the magnetic pole 33 are connected to form a magnetic path between the magnetic pole 32 and the magnetic pole 33.

However, since a separator 31 made of a non-magnetic material is disposed between the magnetic poles 32 and 33, the sealing ring 5 is attached to the cylinder liner in the gap between the separator 31 and the cylinder liner 11. 11 and isolates the combustion chamber 4 from the outside, the crankcase.

As the piston 2 slides, the sealing ring 5 also slides, but when the controller 7 detects that the piston 2 has reached a position near top dead center based on the detection signal from the position sensor 62, the excitation coil 44 is activated. Supply electricity.

Then, a closed circuit of magnetic flux is generated along the magnetic flux lines shown in FIG. 2, and the sealing ring 5 is divided into upper and lower halves. At this time, the sealing ring 5
Since the coercive force acting on the ring is caused by the magnetic force from the permanent magnet 3 and the excitation coil 44, the ring seal 5 is strongly held.

When an explosion occurs inside the combustion chamber 4, the combustion chamber 4
The internal pressure becomes high. The high pressure first acts on the compression ring 22. Since the compression ring 22 is similar to a conventional piston ring, it has the abutment portion as described above, so that a small amount of combustion gas leaks toward the sealing ring 5 side. However, since the leaked combustion gas is sufficiently reduced in pressure when passing through the abutment of the compression ring 22, and the sealing ring 5 is strongly held, the combustion chamber 4
can be completely sealed.

Then, the excitation coil 44 continues to be energized until the piston 2 moves a predetermined amount from the top dead center, that is, 40 degrees in crank angle as described above.

Furthermore, as the piston 2 descends, the lubricating oil adhering to the inner circumferential surface of the cylinder liner 11 is scraped off toward the crankcase by the seal ring 5 and does not enter the combustion chamber 4 .

By the way, the reason why the head end surface of the piston 2 is covered with the heat insulating layer 21 is that the permanent magnet 3 is heated through the piston 2 by heat transfer from the combustion chamber 4, and the permanent magnet 3 is heated beyond the Curie point. This is to prevent the magnet from being demagnetized or demagnetized.

Further, since the core 43 is disposed within the pipe line 13, it is cooled by the cooling fluid circulating in the pipe line 13, so that the magnetism is not impaired.

Furthermore, since the heat insulating gasket 14 is disposed between the headliner 15 and the cylinder liner 11, which are subject to high temperatures, heat conduction from the headliner 15 to the cylinder liner 11 is suppressed.

Although the embodiments of the present invention have been described in detail above, various different embodiments can be easily constructed without departing from the spirit of the present invention. It is not limited to a particular embodiment.

(Effects of the Invention) As described above, according to the present invention, a permanent magnet is provided around the outer periphery of the piston, and a sealing ring made of magnetic fluid is attracted to the permanent magnet to seal the combustion chamber. In addition, especially when the pressure in the combustion chamber is high near top dead center, the magnetic force of both the permanent magnet and the fixed electromagnet strongly holds the magnetic fluid and seals the combustion chamber, thereby creating a seal between the cylinder liner and the outer peripheral surface of the piston. It is possible to completely prevent the leakage of blow-by gas from the combustion chamber and the intrusion of lubricating oil into the combustion chamber.

Further, since the permanent magnet and the fixed electromagnet are insulated from the combustion heat generated in the combustion chamber, the magnetic force does not decrease and the holding force of the magnetic fluid does not attenuate.

Furthermore, since the number of piston rings that press against the inner wall of the cylinder as in conventional engines is reduced, it is possible to provide a cylinder seal device that reduces engine friction loss.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the cylinder part of the engine of this embodiment;
FIG. 2 is an enlarged view of the permanent magnet 3. DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Piston, 3... Permanent magnet, 4... Combustion chamber, 5... Ring seal, 6... Rotating shaft,
7... Controller, 11... Cylinder liner, 1
4...Insulating gasket, 15...Headliner, 3
1... Separator, 43... Core, 44... Excitation coil.

Claims (5)

[Claims] (1) A piston whose head end surface is covered with a heat insulating layer, a permanent magnet having an annular movable magnetic pole disposed around the outer peripheral surface of the piston, and a movable magnetic pole located near the top dead center of the piston. an electromagnet having a fixed magnetic pole facing the above, a cooling device for cooling the electromagnet with a working fluid, and energizing the electromagnet when the movable magnetic pole and the fixed magnetic pole face each other to form a closed circuit of magnetic flux between the two magnetic poles. An energization control means, which is continuously interposed on the entire circumference between the movable magnetic pole and the inner peripheral surface of the cylinder liner, forms a part of the closed circuit of the magnetic path when the electromagnet is energized, and forms a part of the closed circuit of the magnetic path when the electromagnet is not energized. 1. A cylinder seal device comprising: a seal ring made of magnetic fluid that forms a path for magnetic flux passing through the cylinder seal device. (2) The cylinder seal device according to claim (1), wherein the piston is made of a non-magnetic material. (3) The cylinder seal device according to claim (1), wherein the piston has at least one piston ring closer to the combustion chamber than the circumferential position of the movable magnetic pole. (4) The cylinder seal device according to claim (1), wherein the cylinder liner is made of a non-magnetic material. (5) The cylinder seal device according to claim 1, wherein the inner peripheral surface of the cylinder liner is coated with chromium (Cr) plating.