BACKGROUND ART In general, an internal combustion engine such as a'vehicle, vessel, and so on, generates power based on cycles of intake, compression, power, and exhaust strokes. In such an internal combustion engine, the intake and exhaust efficiency is an important factor affecting an engine power and a fuel/air ratio.

In such suction and exhaust, the exhaust is accomplished by a piston's ascent and a combustion pressure, so that exhaust gas in the cylinder is released through an exhaust port in high temperature, high pressure, and as high a speed as exceeding a speed of Mach due to a remaining pressure in the cylinder after the combustion as soon as a discharge value is opened, whereas the suction is accomplished by a negative pressure occurring due to a piston's descent, so that a suction pressure is not so high that suction resistance is increased as air passes through an air filter and a suction port and, accordingly, it is difficult for an amount of air to be fully suctioned in the cylinder.

Further, if a suction valve is closed immediately after the completion of a suction stroke, a part of air being suctioned collides with the suction valve to flow back in a reverse direction, and such a reverse air flow interferes with air to be suctioned on a next suction stroke, to thereby lower an engine power output.

In the meantime, in case that, on the exhaust stroke, exhaust gas of high speed, high temperature, and high pressure which is exhausted through each exhaust port remains in an exhaust manifold or exhaust pipe, vibration is

generated on the exhaust manifold or exhaust pipe due to the remaining exhaust gas, and such vibration causes exhaust noise.

In vehicles, the biggest technical subject on engine performance enhancements is to rapidly exhaust such exhaust gas of high speed, high temperature, and high pressure outside a cylinder and suction fresh air inside the cylinder.

DISCLOSURE OF INVENTION Accordingly, it is an object of the present invention to provide a device for communicating intake and exhaust ports of multicylinder internal combustion engines which transports an explosive exhaust pressure from an exhaust stroke in one cylinder into another cylinder on a corresponding suction stroke as a suction pressure to improve an air suction speed and an air intake amount, and temporarily stores suction gas remaining in the suction pipe after the suction stroke and intakes the suction gas at a high speed into the cylinder on a next suction stroke to restrain suction interference so as to improve suction efficiency, and temporarily stores a part of the exhaust gas exhausted in a high pressure on the exhaust stroke and exhausts the stored exhaust gas after a predetermined period of time lapses, to thereby reduce vibration generations and exhaust noise induced due to the vibration.

In a device for communicating intake and exhaust ports of multicylinder internal combustion engines having plural cylinders wherein a cylinder performs at least a part of an intake stroke as another cylinder is on an exhaust stroke corresponding to the intake stroke, a device for communicating intake and exhaust ports of multicylinder internal combustion engines according to the present invention comprises a first booster pump a lower part of which communicates with an exhaust port of a first cylinder; a second booster pump a lower part of which communicates with an intake port of a second cylinder; and a pressure transfer pipe both ends of which communicate with upper parts of the first and second booster pumps respectively, and filled with hydraulic fluid therein, wherein a pressure of exhaust gas flowing into a lower part of the first booster pump is transferred to the second booster pump through the pressure transfer pipe to increase amount and velocity of air suctioned into the second

cylinder.

Further, the first booster pump according to a preferred embodiment of the present invention includes a first booster cylinder a lower part of which communicates with an exhaust port of the first cylinder; a first piston having a head part slidably installed on the inner circumference of the first booster cylinder and a rod upwardly protruded from the center of the head part; a first cylinder head sealing an upper open part of the first booster cylinder, mounted for the rod of the first piston to slidably move on the inner circumference thereof, and having a first motion pipe formed on the center thereof to which one end of the pressure transfer pipe is connected; and an elastic member elastically mounted in the first cylinder head in an initial state that the first piston is located in a lower side of the first booster cylinder.

Further, the second booster pump according to a preferred embodiment of the present invention includes a second booster cylinder a lower part of which communicates with an intake port of the second cylinder; a second piston having a head part slidably installed on the inner circumference of the second booster cylinder and a rod upwardly protruded from the center of the head part; and a second cylinder head sealing another open end of the second booster cylinder, mounted for the rod of the first piston to slidably move on the inner circumference thereof, and having a second motion pipe formed on the center thereof to which the other end of the pressure transfer pipe is connected.

BRIEF DESCRIPTION OF THE DRAWINGS The above object and other features of the present invention will become more apparent by describing in detail a preferred embodiment thereof with reference to the attached drawings, in which: Fig. 1 is a view for schematically showing a device for communicating intake and exhaust ports of multicylinder internal combustion engines according to an embodiment of the present invention; Fig. 2 and Fig. 3 are views for schematically showing an operation cycle of the device for communicating intake and exhaust ports of multicylinder internal combustion engines according to an embodiment of the present invention; and

Fig. 4 is a view for schematically showing a state that the device for communicating intake and exhaust ports of multicylinder internal combustion engines according to an embodiment of the present invention is mounted.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the structures, features, and operations of a device for communicating intake and exhaust ports of multicylinder internal combustion engines according to a preferred embodiment of the present invention will be described in detail.

As shown in Fig. 1 to Fig. 3, a device for communicating intake and exhaust ports of multicylinder internal combustion engines according to a preferred embodiment of the present invention includes a first booster pump 10 the lower part of which communicates with an exhaust valve 1 a of a cylinder S1, a second booster pump 20 the lower part of which communicates with an intake port 2a of another cylinder S2, a pressure transfer pipe 30 filled with hydraulic fluid such as oil therein and the both ends of which communicate with the upper part of the first booster pump 10 and the upper part of the second booster pump 20, and a bubble removal unit 40 mounted in a predetermined location of the pressure transfer pipe 30 to remove air bubbles occurring upon the initial filling or refilling of hydraulic fluid.

The first booster pump 10 includes, as shown in Fig. 1 to Fig. 3, a first booster cylinder 11 the lower part of which communicates with the exhaust valve 1a of the cylinder S1, a first piston 12 sliding on the inner circumference of the first booster cylinder 11, a first cylinder head 13 sealing the open upper part of the first booster cylinder 11, a coil spring 14 elastically mounted in the first cylinder head 13 in an initial state that the first piston 12 is positioned on the lower part of the first booster cylinder 11.

In here, the first piston 12 has a head part 121 that is slidably and tightly contacted with the inner circumference of the first booster cylinder 11, and a rod 122 upwardly protruded from the center of the head part 121, and on the center portion of the first cylinder head 13 is incorporated a first motion pipe 13a the lower end of which the rod 122 of the first piston 12 is slidably installed and the upper end of which one end of the pressure transfer pipe 30 is connected to.

On the outer side of the head part 121 of the first piston 12 is mounted a seal ring 15 that maintains the sealing of the lower and upper portions and withstands an exhaust gas pressure of high temperature, and on the outer side of the road 122 is mounted an O-ring 16 that prevents the leakage of hydraulic fluid flowing into the first locomotion pipe 13a. Accordingly, exhaust gas flowing into the lower part of the first booster cylinder 11 is prevented from flowing into the upper part of the head part 121 by the seal ring 15, and hydraulic fluid flowing into the upper end of the first locomotion pipe 13a is prevented by the O-ring 16 from flowing into the first booster cylinder 11.

On the first cylinder head 13 is connected an air pipe 17 taking atmospheric air in or out of the upper part of the first booster cylinder 11 to minimize the interference due to pressure changes between the upper and lower sides of the first piston 12 upon the reciprocations of the first piston 12.

The air pipe 17, as shown in Fig. 4, communicates with different first booster pumps 50,60, and 70 which communicate with exhaust ports of different cylinders S2, S3, and S4, and is exposed to air.

The second booster pump 20, as shown in Fig. 1 to Fig. 3, includes a second booster cylinder 21 the lower part of which communicates with an intake port 2a of the cylinder S2, a second piston 22 sliding on the inner circumference of the second booster cylinder 21, a second cylinder head 23 sealing the open upper part of the second booster cylinder 21, and a damping member 24 provided on the upper inner circumference of the second booster cylinder 21 and damping shocks upon the ascent of the second piston 22.

In here, the second piston 22 is constructed with a head part 221 slidably contacted with the inner circumference of the second booster cylinder 21, and a rod 222 upwardly protruded from the center of the head part 221, and on the center portion of the second cylinder head 23 is incorporated a second motion pipe 23a through the lower part of which the road 222 of the second piston 22 is slidably mounted and to the upper part of which the other end of the pressure transfer pipe 30 is connected.

An O-ring 25 is respectively installed on the outer sides of the head part 221 of the second piston 22 and the rod 222 to maintain the sealing of the lower and upper parts. Accordingly, air flowing into the lower part of the

second booster cylinder 21 is prevented by the O-ring 25 from flowing to the upper part of the head part 221, and hydraulic fluid flowing into the upper part of the second locomotion pipe 23a is prevented by the O-ring 25 from flowing into the second booster cylinder 21.

On the second cylinder head 23 is connected an air intake pipe 26 for the air of the intake port 2a to flow in and out of the upper inner part of the second booster cylinder 21 to minimize the interference due to a pressure difference between the upper and lower parts of the second piston 22 upon the reciprocations of the second piston 22. The intake pipe 26, as shown in Fig. 4, communicates with different second booster pumps 80,90, and 100 which communicate with the intake ports of the cylinders S1, S3, and S4, and communicates with any one of the intake part. At this time, on a branch pipe branched from the air intake pipe 26 and connected to any one of the intake ports is installed a check valve 27 that constantly maintains a pressure difference between the lower and upper sides of the second piston 22. The check valve 27 maintains a pressure of the lower part of the second piston 22 higher than that of the upper part of the same in order for the second piston 22 to ascend with ease.

In the meantime, the exhaust valve 1a and the first booster cylinder 11 communicate with each other at an acute angle so that exhaust gas can flow into the first booster cylinder 11 with ease, and the intake port 2a and the second booster cylinder 21 communicate with each other at an acute angle so that the air in the first booster cylinder 21 can be suctioned into a cylinder 2 with ease through the intake port 2a.

A reference numeral 11 a, not described, indicates heat sink pins formed on the outer wall of the first booster cylinder 11 to widen a contact area with ambient air, to thereby promote the cooling of the first booster cylinder 11.

The operations of the device for communicating the intake and exhaust ports of multicylinder internal combustion engines constructed as above according to an embodiment of the present invention will be described with reference to Fig. 2 and Fig. 3. The two cylinders shown in Fig. 2 and Fig. 3 are the cylinders alternating intake strokes and exhaust strokes in synchronization with each other.

Fig. 2 is a view for showing the operation states of the first and second booster pumps as the exhaust stroke is ongoing in a cylinder and the intake stroke is ongoing in a different cylinder in synchronization with the exhaust stroke. As shown in Fig. 2, if the exhaust stroke is ongoing in the cylinder S1, exhaust gas of high speed, high temperature, and high pressure is discharged through the exhaust valve 1a. The discharged exhaust gas flows into the lower part of the first booster cylinder 11, and a pressure of the exhaust gas ascends the first piston 12. The ascent of the first piston 12 causes the rod 122 to press the hydraulic fluid of the first locomotion pipe 13a out so that the hydraulic fluid of the pressure transfer pipe 30 moves into the second booster pump 20. The moving hydraulic fluid flows into the second locomotion pipe 23a to press the rod 222, so that the second piston 22 descends. If the second piston 22 descends, air taken in the second booster cylinder 21 is pushed out to the intake port 2a at a high speed, and such an intake air flow increases the velocity and amount of air to be suctioned into the cylinder S2.

After such a procedure, the exhaust stroke is completed in the cylinder S1, and the intake, compression, and power strokes subsequently progress in turn, whereas the cylinder S2 completes the intake stroke, and subsequently proceeds with the compression, power, and exhaust strokes in turn.

Fig. 3 is a view for showing the operation states of the first and second booster pumps as the intake stroke is ongoing in a first cylinder and the compression stroke is ongoing in a second cylinder in synchronization with the intake stroke. As shown in Fig. 3, if the cylinder S1 completes the exhaust stroke, the exhaust valve 1a is closed to stop discharging the exhaust gas, the first piston 12 of the first booster pump 10 which is located at the top dead center on the exhaust stroke descends by an elastic force of the coil spring 14.

The descent of the first piston 12 applies an intake pressure to the inside of the first motion pipe 13a, and the intake pressure causes the hydraulic fluid moved in the second booster pump 20 to flow back, and an intake pressure occurring upon the flowback of the hydraulic fluid ascends the second piston 22 of the second booster pump 20. At the same time, the suctioned air remaining in the cylinder S2 flows into the lower part of the second booster cylinder 21, so that collisions between air to be freshly taken in as a subsequent intake stroke

progresses and the remaining air are prevented as well as the remaining air is discharged into the intake port 2a at a high speed by the descent of the second piston 22 upon the subsequent intake stroke to flow into the inside of the cylinder S2, to thereby enhance the air intake efficiency.

INDUSTRIAL CAPABILITY As described above in detail, the device for communicating intake and exhaust ports of multicylinder internal combustion engines transports an explosive exhaust pressure in a cylinder on the exhaust stroke into another cylinder on the intake stroke corresponding to the exhaust pressure as an air intake pressure, to thereby increase the air intake velocity and amount.

Further, the device temporarily stores the suctioned air remaining in an intake port just after an intake stroke and suctions the air into a cylinder at a high speed upon a subsequent intake stroke, to thereby suppress air intake interference and enhance the air intake efficiency.

Moreover, the device temporarily stores a part of exhaust gas discharged in a high pressure upon an exhaust stroke and discharges the exhaust gas after a predetermined period of time, to thereby lower vibration generations and exhaust noise occurring due to the vibration.