JP3919598B2 - Two-cycle internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-cycle internal combustion engine in which the inside of a cylinder is scavenged by introduction of intake air from a scavenging port to the lower portion of the cylinder.
[0002]
[Prior art]
Generally, in this type of two-cycle internal combustion engine, as is well known, the intake air from the scavenging port to the lower part of the cylinder is exhausted at the top of the cylinder while turning in the circumferential direction in the cylinder. Provided on the opposite side of the scavenging port while swirling in the axial direction of the cylinder in the uniflow type that gives a swirl flow that rises toward the port and the intake from the scavenging port to the lower part of the cylinder There is a loop scavenging type that gives a loop flow that flows toward the exhaust port.
[0003]
However, the conventional two-cycle internal combustion engine has a configuration in which the direction of the swirl flow or loop flow from the scavenging port is always fixed so as to be a constant direction. there were.
[0004]
[Problems to be solved by the invention]
That is, if the flow direction of the swirl flow or loop flow in the intake air into the cylinder is always constant, combustion in the cylinder is always performed only at a certain same location in the cylinder. The temperature at the inner wall of the cylinder is always the highest temperature at the same specific location as described above. In other words, the highest temperature due to combustion is limited to the specific same location as described above, and the heat load due to combustion is the highest. However, it will be concentrated on the same specific place as described above.
[0005]
For this reason, not only does the oil film breakage of the lubricating oil on the piston occurs at the location where the thermal load is concentrated, but also a lot of combustion deposits adhere to this location, and the thermal load is concentrated. For this reason, there has been a problem that uniform cooling in each place in the internal combustion engine, and hence uniform heat distortion in each place in the internal combustion engine, cannot be achieved.
[0006]
An object of the present invention is to provide a two-cycle internal combustion engine that solves these problems.
[0007]
[Means for Solving the Problems]
In order to achieve this technical problem, claim 1 of the present invention provides:
“In a two-cycle internal combustion engine that has a scavenging port into the cylinder at the bottom of the cylinder,
The scavenging port includes one scavenging port that generates a swirl flow swirling in a circumferential direction in the cylinder and another scavenging port that generates a swirl flow in a direction different from the one scavenging port in the cylinder. In this configuration , the intake air into the cylinder is alternately switched between intake air from the one scavenging port and intake air from the other scavenging port every one or more combustion strokes. "
It is characterized by that.
[0008]
Further, claim 2 of the present invention is
“In a two-cycle internal combustion engine that has a scavenging port into the cylinder at the bottom of the cylinder,
The scavenging port is composed of one scavenging port that generates a loop flow that pivots in the axial direction in the cylinder and the other scavenging port that generates a loop flow in a direction different from the one scavenging port in the cylinder. Then, the intake air into the cylinder is alternately switched between the intake air from the one scavenging port and the intake air from the other scavenging port every one or more combustion strokes . "
It is characterized by that.
Furthermore, claim 3 of the present invention provides
“In the first or second aspect of the invention, the alternate switching is performed by a rotary valve provided to rotate in conjunction with an internal combustion engine in the intake passage to the one scavenging port and the other scavenging port. Was configured . "
It is characterized by that.
[0009]
[Operation and effect of the invention]
With this configuration, the direction of the swirl flow or loop flow in the intake air in the cylinder changes alternately every one or more combustion strokes, and the point where the highest temperature is reached by combustion is once or more than one. Each time the combustion stroke is changed, it changes to different places. As a result, it is possible to avoid concentrating the heat load at a specific place as in the prior art, and the heat load can be distributed to a plurality of places. It is possible to reliably reduce the occurrence of oil film breakage in the lubricating oil and the attachment of a large amount of combustion deposits at specific locations, as well as to ensure uniform cooling at each location in the internal combustion engine and, in turn, uniform thermal distortion at each location in the internal combustion engine. Can be achieved.
[0010]
In particular, according to the configuration described in claim 3 , the intake air can be alternately switched every one or more combustion strokes by a rotary valve that rotates in conjunction with the internal combustion engine. The switching structure can be made compact and switching control can be accurately performed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0012]
1 and 2 show a first embodiment.
[0013]
In this figure, reference numeral 1 denotes a cylinder block in a compression ignition type uniflow type two-cycle internal combustion engine. In this cylinder block 1, a cylinder 2 having a piston 3 which reciprocates in conjunction with a crankshaft (not shown) is incorporated. A combustion chamber 4 is formed in a recess on the top surface of the piston 3.
[0014]
On the other hand, a cylinder head 5 is fastened to the upper surface of the cylinder block 1 so as to close the top of the cylinder 2. The cylinder head 5 includes an exhaust port 7 having an exhaust valve 6, and a fuel injection. A valve 8 is provided so as to look into the approximate center of the cylinder 2 in plan view.
[0015]
In this case, the exhaust valve 6 is connected to the piston 3 before the bottom dead center (for example, about 70 degrees before the bottom dead center at the crank angle) and after the bottom dead center (for example, the bottom dead center at the crank angle). The fuel injection valve 8 is configured to inject and supply fuel at a time around the top dead center of the piston 3 so as to open during a period up to 60 degrees.
[0016]
In the lower part of the cylinder 2 of the cylinder block 1, a plurality of one scavenging port 9 is drilled in the left half portion of the circumference, and a plurality of the other scavenging ports 10 are drilled in the right half portion, These scavenging ports 9 and 10 are moved by the reciprocating motion of the piston 3 so that the timing before the bottom dead center (for example, about 45 degrees before the bottom dead center in the crank angle) and the timing after the bottom dead center (for example, the crank angle). In the period up to 45 degrees before and after the bottom dead center).
[0017]
In this case, one scavenging port 9 in the left half of the scavenging ports 9, 10 is connected to the intake air flowing into the cylinder 2 from the one scavenging port 9, as shown by a solid arrow A in the figure. While configured to give a swirl flow swirling in the clockwise direction, each other scavenging port 10 in the right half is indicated by a dotted arrow B in the drawing to the intake air flowing into the cylinder 2 from the other scavenging port 10. Thus, a swirl flow that turns in a different direction from the one scavenging port 9, that is, in the present embodiment, the opposite counterclockwise direction is applied.
[0018]
Reference numeral 11 denotes an exhaust turbocharger in which a blower type compressor 11b is directly connected to an exhaust turbine 11a. At the outlet of the exhaust turbine 11a in the exhaust turbocharger 11, exhaust to the atmosphere is provided. An air intake conduit 13 from the atmosphere is connected to the pipe 12 on the suction side of the compressor 11b.
[0019]
An exhaust passage 14 from the exhaust port 7 is connected to the entrance of the exhaust turbine 11a.
[0020]
Then, the main intake passage 15 from the discharge port in the compressor 11 b is branched into one intake passage 16 and the other intake passage 17, and the one intake passage 16 is distributed to the one scavenging port 9. 18, the other intake passage 17 is connected to the distribution chamber 19 for each of the other scavenging ports 10.
[0021]
In addition, a rotary valve 20 that rotates in conjunction with the crankshaft by rotation transmission from a crankshaft (not shown) is provided at a branch portion from the main intake passage 15 to both the intake passages 16 and 17. When the intake air from the compressor 10b is supplied from the one scavenging port 9 by rotation and when the intake air is supplied from the other scavenging port 10, the crankshaft is rotated every one or more rotations. That is, it is configured to alternately switch every one or more combustion strokes.
[0022]
In this configuration, when intake into the cylinder 2 is performed from one of the scavenging ports 9, a swirl flow swirling clockwise as shown by a solid arrow A in the drawing is applied to the cylinder 2, Further, when intake into the cylinder 2 is performed from each one of the scavenging ports 9, the cylinder 2 has a direction different from that of the one scavenging port 9, as indicated by a solid arrow B in the drawing. In the embodiment, a swirl flow swirling in the opposite counterclockwise direction is applied.
[0023]
In this case, the case where the intake from the one scavenging port 9 is performed and the case where the intake from the other scavenging port 10 is performed are performed once by the rotation of the rotary valve 18 linked to the rotation of the internal combustion engine. By alternately repeating each combustion stroke or multiple combustion strokes, the location where the highest temperature is reached by combustion changes to a different location alternately during one or more combustion strokes, and as a result Since the load can be prevented from being concentrated at a specific location as in the prior art, the thermal load can be distributed to a plurality of locations.
[0024]
Next, FIGS. 3 and 4 show a second embodiment.
[0025]
In this second embodiment, a pair of left and right rotary valves 21 that rotate in conjunction with a crankshaft (not shown) are provided on the left and right sides of the lower part of the cylinder 2 containing the reciprocating piston 3 '(this is not shown). The rotary valve 21 may be provided on only one of the left and right sides of the cylinder 2), and the rotary valve 21 generates a swirl flow swirling in the direction indicated by the solid line arrow A 'in the cylinder 2'. The scavenging port 9 'and the other scavenging port 10' for generating a swirl flow swirling in different directions (in the reverse direction in the present embodiment) indicated by a dotted arrow B 'are provided in the cylinder 2'. Of the rotary valves 21, the distribution chamber 18 ′ for one rotary valve 21 and the distribution chamber 19 ′ for the other rotary valve 21 are the same as those in the first embodiment. To, respectively coupled 'to the other intake passage 17' while the intake passage 16 from the compressor in the exhaust turbo supercharger and.
[0026]
Then, by shifting the phase of one scavenging port 9 ′ and the phase of the other scavenging port 10 ′ in each rotary valve 21, the rotation of the rotary valve 21 causes the intake air from the compressor to be When supplying from one scavenging port 9 ′ and when supplying from the other scavenging port 10, the crankshaft is rotated once or a plurality of rotations, that is, one combustion stroke or a plurality of combustions. It is configured to switch alternately for each stroke.
[0027]
Also in this configuration, as in the first embodiment, the case where the intake from one scavenging port 9 'and the case where the intake from the other scavenging port 10' is performed affect the rotation of the internal combustion engine. Since the rotation of the rotary valve 21 that is interlocked is repeated alternately for each combustion stroke or each of a plurality of combustion strokes, the point at which the highest temperature is reached by the combustion is alternated for every one or more combustion strokes. It is possible to avoid changing to different places, and consequently, to concentrate the heat load at a specific place as in the prior art, and to distribute the heat load to a plurality of places.
[0028]
Each of the above embodiments has been applied to a two-cycle internal combustion engine using an exhaust turbocharger. However, the present invention is not limited to this, and an internal combustion engine can be used instead of the exhaust turbocharger. The same applies to a two-cycle internal combustion engine using a mechanical supercharger driven by the engine.
[0029]
In addition, the present invention is not limited to the compression ignition type two-cycle internal combustion engine as in the above-described embodiment, but is a spark ignition type two-cycle internal combustion engine using a spark plug 22 provided as shown by a two-dot chain line in FIG. The same applies to.
[0030]
Furthermore, the present invention is a uniflow type that applies a swirl flow that rises toward the exhaust port at the top of the cylinder while turning in the circumferential direction in the cylinder as in the above-described embodiments. Not only a two-cycle internal combustion engine, but also a conventionally well-known loop scavenging type two-cycle, which provides a loop flow that flows toward an exhaust port provided on the opposite side of the scavenging port while turning in the axial direction in the cylinder The same applies to an internal combustion engine.
[0031]
That is, in the case of this loop scavenging type two-cycle internal combustion engine, as shown in FIG. 5, a solid line arrow is drawn between the first scavenging port 22a and the first exhaust port 23a opposed thereto for intake into the cylinder 2 ″. In addition to the configuration in which a loop flow indicated by A ″ is applied, a dotted arrow B ″ is formed by a second scavenging port 22b that is displaced perpendicularly to the first scavenging port 22a and a second exhaust port 23b that faces the second scavenging port 22b. The respiration flows in different directions as shown in FIG. 1 are applied, and the intake air is supplied into the cylinder 2 ″ once in the intake air from the first scavenging port 22a and the intake air from the second scavenging port 22b. It is configured so as to be switched alternately every plural combustion strokes.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional front view showing a main part of a first embodiment.
FIG. 2 is an enlarged sectional view taken along the line II-II in FIG.
FIG. 3 is a longitudinal sectional front view showing a main part of a second embodiment.
4 is an enlarged sectional view taken along line IV-IV in FIG. 3;
FIG. 5 is a perspective view showing a case where the present invention is applied to a loop scavenging type.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder block 2,2 ', 2 "Cylinder 3,3' Piston 5 Cylinder head 6 Exhaust valve 7 Exhaust port 8 Fuel injection valve 9, 9 'One scavenging port 10, 10' The other scavenging port 11 Exhaust turbo supercharging Machine 16, 16 ', 17, 17' Intake passage 20, 21 Rotary valve 22a, 22b Scavenging port 23a, 23b Exhaust port

Claims (3)

In a two-cycle internal combustion engine in which a scavenging port into the cylinder is provided at the bottom of the cylinder,
The scavenging port includes one scavenging port that generates a swirl flow swirling in a circumferential direction in the cylinder, and another scavenging port that generates a swirl flow in a direction different from the one scavenging port in the cylinder. configuring, the intake air into the cylinder, the intake from the intake and the other scavenging ports from the scavenging port of the one, characterized in that alternately switched every one or more combustion stroke Two-cycle internal combustion engine. In a two-cycle internal combustion engine in which a scavenging port into the cylinder is provided at the bottom of the cylinder,
The scavenging port is composed of one scavenging port that generates a loop flow that pivots in the axial direction in the cylinder and the other scavenging port that generates a loop flow in a direction different from the one scavenging port in the cylinder. Then, the intake air into the cylinder is alternately switched between the intake air from the one scavenging port and the intake air from the other scavenging port every one or more combustion strokes. Cycle internal combustion engine. 3. The method according to claim 1, wherein the alternate switching is performed by a rotary valve provided to rotate in conjunction with an internal combustion engine in an intake passage to the one scavenging port and the other scavenging port. A two-cycle internal combustion engine characterized by comprising

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