KR20000055570A - Shock-absorbing piston of internal- combustion engine - Google Patents

Abstract

PURPOSE: A shock absorbing piston of an internal combustion engine is provided to improve a shock absorbing structure to make a piston head applied by a relatively small amount of shock. CONSTITUTION: At the top point of a piston(10'), that is, at the end of a compression stroke, the compressed fuel in a combustion chamber is ignited for an expansion stroke. The combustion gas immediately after ignition has a higher pressure than elasticity of a spring(23). Thereby, an auxiliary piston(21) is pushed as compressing the spring(23) to absorb a shock in a moment of explosion with the spring(23) through the auxiliary piston(21). Thus, it is rare that the piston is interrupted by the shock or the shock is delivered to a load through a connecting rod at the top point of the piston(10').

Description

Shock absorption piston of internal combustion engine {SHOCK-ABSORBING PISTON OF INTERNAL- COMBUSTION ENGINE}

The present invention relates to a shock absorbing piston of an internal combustion engine used as a power source of various means of transportation and machinery, and in particular, absorbs and minimizes the impact applied at the moment of explosion for an expansion stroke, and furthermore, The present invention relates to a piston of a regenerative shock-absorbing structure capable of storing shock and regenerating it in piston motion.

As is well known, an internal combustion engine is a heat engine that explosively burns fuel mixed with air in a cylinder to reciprocate a piston, and forms an intake-compression-expansion-exhaust cycle according to the reciprocation of the piston. .

1 is a schematic diagram showing a gasoline engine which uses an electric ignition system and constitutes a 4-stroke 1 cycle to explain an outline of an internal combustion engine. In the drawings, reference numeral 1 denotes a cylinder, 2 an intake valve, 3 an exhaust valve, and 4 an ignition plug. The piston 5 reciprocates between the top dead center and the bottom dead center in the cylinder 1, and the reciprocating motion of the piston 5 is changed to the rotational movement of the crank 7 through a connecting rod 6. have. In the figure, reference numeral 8 denotes a combustion chamber in which compression and explosion occur between the cylinder inner wall and the piston head (upper surface).

The conventional piston 5 used conventionally is a cylindrical body having a head 5a which is a part directly priced by a high temperature and high pressure combustion gas as shown in FIG. The cylindrical body also penetrates laterally to fit three ring grooves (5b) for fitting piston rings (not shown) for airtightness with the cylinder inner wall, and piston pins (not shown) for connecting rods. To have a hole (5c). Although the head 5a is generally planar here, in the case of a diesel engine, it may be a moderately concave shape in order to form a combustion chamber.

Briefly describing the process in which the four strokes of the piston 5 are made, first, when the intake valve 2 of one side of the cylinder 1 is opened and the exhaust valve 3 is closed, the piston 5 is lowered from the top dead center position. An intake stroke is performed in which fuel (gasoline) mixed with air is sucked into the combustion chamber 8 in the cylinder 1 through the intake valve, and then the intake valve 2 is closed and the piston 5 is closed at its bottom dead center. Ascending to the point results in a compression stroke in which fuel mixed with air is compressed to high temperature and high pressure in the cylinder combustion chamber 8. If the ignition plug 4 is operated when the piston 1, which is the point at which the compression stroke ends, is near the top dead center, the compressed fuel explodes and explodes rapidly, and the combustion gas expands rapidly. An expansion stroke is performed in which the piston 5 head 5a is charged and lowered by the pressure. The downward movement of the piston 5 by this expansion stroke is changed to the rotational movement of the crank 7 through the connecting rod 6. On the other hand, the crank 7 is provided with the flywheel which is not shown in figure. The flywheel is rotated with inertia equivalent to a large mass so that the piston 5 can be easily turned at top dead center and bottom dead center. That is, the piston 5 rises to the top dead center again at the bottom dead center where the expansion stroke is completed. At this time, the exhaust valve 3 opens to exhaust the combustion gas in the combustion chamber 8 of the cylinder 1 to the outside. will be.

For reference, diesel engines that use light oil or heavy oil as fuel, unlike gasoline engines, inject and compress only air to directly ignite fuel oil (light oil or heavy oil) where the air pressure and temperature increase. The cycle is achieved by adiabatic expansion of the combustion gas in a compression ignition manner.

In an internal combustion engine, the piston head is periodically charged by the combustion gas pressure in the expansion stroke. The problem is that since the conventional piston has a simple structure that cannot absorb shock by itself, it is periodically subjected to a significant impact, and thus a periodic piston knock is generated.

The impact when the piston is priced at a position beyond the top dead center will be relatively less, but it is generally known that combustion is best done just before the end of the compression stroke, ie, just before the piston reaches top dead center. If the combustion gas pressure acts before the piston reaches the top dead center, the piston motion is disturbed and the output is lowered.In addition, when the piston reaches the top dead center, when the connecting rod and the crank are placed vertically in a straight line, the combustion gas The pressure does not play any role in the piston's motion and acts as a very big shock that only strikes the piston. The shock applied to the piston is transmitted to the load side through the connecting rod as it is, giving a mechanical force.

As such, the priced impact when the piston is near the top dead center is not only a direct cause of much mechanical noise and reduced power, but also shortens the life by promoting wear of the cylinder inner wall and the piston. In addition, the compression performance of the piston is reduced, causing incomplete combustion of the fuel, which has a significant effect on the increase of fuel consumption and soot increase.

In order to solve this problem, the present applicant has created a "shock absorbing axial connecting rod" which absorbs and stores the piston shock at the connecting rod and regenerates the impact force by the piston motion, before the present invention, to patent application No. 10442. It has been filed and registered.

It is an object of the present invention to provide an improved piston with a shock absorbing structure in which a piston head directly charged with combustion gas pressure is relatively less impacted.

As another object, the axial shock absorbing structure that can solve the above problems by absorbing the shock from the piston head directly priced by the combustion gas pressure to minimize the impact and store the absorbed shock to regenerate the piston movement. It is intended to provide an improved piston.

1 is a schematic diagram showing a four-stroke cycle gasoline engine to explain the principle of an internal combustion engine;

Figure 2 is a perspective view showing a partially cut piston of a conventional internal combustion engine used in the prior art.

Figure 3 is a perspective view showing the shock absorbing piston of the internal combustion engine according to the first embodiment of the present invention (an enlarged cross-sectional view of a portion of the head surface of the piston).

Figures 4a and 4b is a plan view showing the shape of the uneven portion formed in the piston head shown in FIG.

Figure 5 is a perspective view showing a partially cut and separated shock absorbing piston of the internal combustion engine coupled to the axial force shock absorbing device according to a second embodiment of the present invention.

Figure 6 is a cross-sectional view showing a coupled state of the axial shock absorbing device shown in FIG.

Figure 7 is a cross-sectional view of the operating state of the axial shock absorbing device shown in FIG.

Explanation of symbols on the main parts of the drawings

10,10 ': Piston 11: Head

12; 12a, 12b: uneven portion 13: shock absorbing room

20: axial shock absorber 21: auxiliary piston

22: guide rod 23: spring member

24: fixed key 25: fixed plate

In the present invention to achieve the first object described above,

In the expansion stroke, the piston head surface, which is charged with the combustion gas pressure, is not simply flat or curved as in the prior art, but uniformly arranged irregularities such as triangular pyramids or square pyramid concave or convex grooves are evenly arranged. Processing to increase the surface area of the head.

In this way, under the same conditions, that is, under the condition that the combustion chamber volume in the cylinder is not changed, the pressure of the entire combustion gas that strikes the piston head is the same, but the force applied to the head as the surface area is enlarged by the uneven portion is increased. The strength of is reduced, the impact is weakened, that is, it can perform the function of shock absorption.

In addition, the present invention to achieve the second object,

At least one concave shock absorbing chamber is formed on the surface of the piston head which is charged with the combustion gas pressure at the expansion stroke, and at least one concave shock absorbing chamber is formed. A corresponding axial shock absorbing device, which is capable of movably receiving another auxiliary piston in the shock absorbing chamber, and contracting and restoring immediately when the auxiliary piston is pushed out by a momentary impact caused by combustion gas pressure. It is constructed by elastically supporting the auxiliary piston in a direction against impact by using a spring member that retains elasticity.

That is, when the piston, which is the end of the compression stroke, is near the top dead center, the auxiliary piston, which is part of the head, ignites and momentarily acts on the combustion gas pressure applied to the combustion gas pressure so as to retreat once while suppressing the spring member. By absorbing the momentary shock caused by the impact, and then restored immediately after the impact, by using the reaction force acting at the restoration, it is configured to assist the piston movement through the action of regenerating the force corresponding to the impact.

In this case, it is preferable that the auxiliary piston has a portion of the top surface of the auxiliary piston, and the spring member is contracted to the instantaneous impact caused by the gas pressure, but retains elasticity sufficiently exceeding the pressure in the combustion chamber acting in the compression stroke. .

More preferably, by forming the concave-convex portions as described above on the head surface and the upper surface of the auxiliary piston, the impact can be more effectively attenuated, absorbed, stored and regenerated.

Hereinafter, with reference to the accompanying drawings will be described in detail preferred embodiments of the present invention.

As a first embodiment, the piston 10 shown in Fig. 3 forms a plurality of concave-convex portions 12 that are evenly disposed on the head 11, as shown in the enlarged cross-sectional view of the circle. For example, the concave-convex portion may be formed such that the concave grooves 12a and 12b having a triangular pyramid shape or a quadrangular pyramid shape as shown in FIG. 4b are evenly arranged in the form of a continuous pattern, as shown in FIG. The protrusions may be formed to increase their surface area.

As described above, the piston 10 having the structure of the head 11 has a surface area of the head 11 widened by a plurality of uneven parts 12; The pressure exerted per unit area is relatively weakened and therefore less impacted by the initial combustion gas pressure.

Next, as a second embodiment, the piston 10 ′ shown in FIG. 5 has a circular shock absorbing chamber 13 formed in two places concave on the surface of the head 11, and in the shock absorbing chamber 13. The axial force absorbing device 20 is coupled to the structure. In the figure, the axial shock absorbing device 20 is coupled to two places, but only one may be provided, and more may be provided to increase the effect. The piston 10 ′ has a structure in which a plurality of uneven parts as described above are formed in the head 11 together with the shock absorbing device 20.

The axial force absorbing device 20 is an auxiliary piston 21 movably received in the shock absorbing chamber 13 formed in the piston head 11, integrally formed in the center under the auxiliary piston 21, the shock absorbing chamber (13) a guide rod 22 inserted into the guide hole 14 formed in the center of the bottom surface to guide the movement of the auxiliary piston 21, and a bottom surface of the shock absorbing chamber 13 while the guide rod 22 is penetrated. A spring member 23 interposed between the bottom of the auxiliary piston 21 and a spring member 23 for elastically supporting the auxiliary piston 21, and a guide hole 14 at the rear side of the guide hole 14 at the bottom of the shock absorbing chamber 13; In order to fix the guide rod 22 of the auxiliary piston 21 passed through the 14 not to be separated, the fixing key 24 and the guide rod 22 which are to be inserted into the key groove 22a of the guide rod 22 are fixed. It is interposed between the inner surface 15 of the piston head 11 and the fixing key 24 while penetrating therethrough, thereby allowing the reciprocating movement of the guide rod 22 to escape upward. It is composed of a fixing plate 25 for fixing it.

A ring groove 21a is formed in the auxiliary piston 21 so that the piston ring 26 may be fitted therein. The piston ring 26 is to prevent the outflow of the combustion gas by hermetically blocking the inner wall of the shock absorbing chamber 13 and the combustion chamber cut out.

The spring member 23 is manufactured in the form of a leaf spring made by cutting the annular high elastic elastic plate at regular intervals in the circumferential direction. Of course, the spring member 23 may use a well-known coil spring.

The fixed plate 25 is a rectangular plate having a large area, and has a hole 25a drilled to penetrate the center guide rod 22, and the corner portion 25b is formed in the imaginary line state shown in FIG. The two-stage bending to fix the fixing key 24 inserted into the key groove 24 of the guide rod 22 to restrain not to relax. The reason for fixing with the fixing key 24 and the fixing plate 25 is to contact the inner surface of the piston head 11 with a large area against the spring member 23 having a strong elasticity to achieve a more stable coupling.

As described above, the spring member 23 is manufactured to have elasticity that is contracted to the instantaneous impact due to the gas pressure and sufficiently exceeds the maximum pressure in the combustion chamber acting in the compression stroke. On the other hand, the auxiliary piston 21 is made of the same material as the piston head 11 so as to have sufficient durability against high temperature and high pressure in consideration of the environment of the cylinder combustion chamber, and receives the elasticity of the spring member 23 to allow the fixing plate 25 to be allowed. The upper surface is at the same height as the surface of the piston head 11 so as to be in charge of a part of the head 11, and the uneven portion 12 as described above on the upper surface and the head 11 when raised to the maximum. ) Was formed.

On the other hand, the seal groove 14a is formed in the inner circumference of the guide hole 14 at the bottom of the shock absorbing chamber, and the oil sealing ring 17 is fitted. The oil seal 17 is kept airtight between the guide rod 22 attached to the auxiliary piston to prevent the oil for cooling and lubrication from the crank chamber under the cylinder.

Hereinafter, the operation of the axial shock absorbing device 20 coupled to the axial shock absorbing piston 10 'will be described.

When the piston 10 'is raised for the compression stroke in the state as shown in FIG. 6, air and fuel sucked into the cylinder combustion chamber of FIG. 1 are compressed, and the spring member 23 is sufficiently elastic than the pressure in the combustion chamber. Since the auxiliary piston 21 is so strong that it is in a state where the upper surface is maintained at the same height as the piston head (11).

When the piston 10 'reaches a top dead center, i.e., when the compressed stroke is ignited, the fuel compressed in the combustion chamber for the expansion stroke is ignited. Since the auxiliary piston 21 is pushed in a state of suppressing the spring member 23 as shown in FIG. 7, the shock priced at the instant of explosion is absorbed by the spring member 23 through the auxiliary piston 21. Therefore, the phenomenon in which the piston 10 'is disturbed by the impact of the piston near the top dead center or the shock is transmitted to the load side through the connecting rod in the vertical state is greatly reduced. On the other hand, the spring member 23 suppressed to absorb the impact is in a state of storing the force because it has a resilient elasticity in equilibrium with the force corresponding to the impact.

Subsequently, when the piston 10 'is lowered through the top dead center by the combustion gas pressure immediately after the impact in the state as shown in FIG. 7, the volume of the combustion chamber is increased so that the pressure is weaker than the elasticity of the spring member 23 suppressed. , It is raised very quickly by the restoring force of the suppressed spring member 23. As such, when the auxiliary piston 21 is raised, the volume of the combustion chamber should be reduced. In fact, with respect to the piston 10 ', the combustion chamber is equal to one solid body, and thus the force stored in the spring member 23 for raising the auxiliary piston 21 is increased. The restoring force corresponding to this acts as a reaction force that presses the piston head 11 backward, thereby accelerating its downward movement.

In other words, while absorbing the shock at the moment when the explosive combustion gas pressure is initially charged, it stores a force corresponding to the impact and regenerates it to an effective output to accelerate the piston movement immediately after the impact.

As described through the above embodiments, the present invention provides a piston that is initially impacted by the explosive combustion gas pressure by knurling the surface of the piston head to increase its surface area, and also absorbs the impact and It is to provide a piston incorporating an axial force shock absorber that can be stored and regenerated to an effective output.

Therefore, the present invention is effective in increasing the output of the internal combustion engine by eliminating the large impact of the initial stage of the expansion stroke in the internal combustion engine, significantly reducing the mechanical noise of the piston knock, and regenerating the effective output by absorbing and storing the impact. In addition, since the present invention minimizes the impact of impact, wear can be reduced, thereby prolonging service life, and also enhancing fuel output by increasing the high power and compression performance of the piston, thereby effectively reducing fuel consumption and soot. .

The present invention is not limited to the above described and illustrated in the drawings, and various modifications and changes can be made within the scope of the following claims.

Claims (5)

A piston of an internal combustion engine accommodated in a cylinder of an internal combustion engine and moved at combustion gas pressure, wherein the internal combustion engine has a plurality of uneven parts formed in the head of the piston body to which the combustion gas pressure is applied to increase its surface area. Shock absorbing piston of the engine. A piston of an internal combustion engine accommodated in a cylinder of an internal combustion engine and moved at combustion gas pressure, the piston comprising: at least one shock absorbing chamber concave on the head surface of the piston body to which combustion gas pressure is applied; And a spring member for holding the auxiliary piston in such a manner as to be resilient to absorb the impact applied to the auxiliary piston, and to support the auxiliary piston in a direction against the impact. Shock absorbing piston. 3. The internal combustion according to claim 2, wherein the auxiliary piston has a guide rod formed to guide the movement, and the guide rod is formed on the bottom of the shock absorbing chamber so as to support the guide rod through the guide rod. Shock absorbing piston of the engine. 4. The shock absorbing piston of an internal combustion engine according to claim 3, further comprising means for fixing the end of the guide rod outside the guide hole so as not to be detached. The shock absorbing piston of an internal combustion engine according to claim 2, wherein a plurality of uneven parts are formed on the head surface of the piston body and the auxiliary piston so as to widen the surface area thereof.