JP2001073780A - Opposed piston type two cycle uniflow engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an exposed part of cylinder by changing the shape of combustion chamber, which is enabled by forming the connecting path between combustion chamber an inner surface of cylinder and combustion chamber, which is formed by cavity and groove formed on the top surface of intake port switching piston and exhaust port switching piston. SOLUTION: When piston 3a, 3b come near to each other at compression stroke, scavenging air in the sleeve 9 flows into cavity 16a, 16b at the top surface of piston without lowering the flow of swirl. By the access of piston 3a and 3b, cavity 16a, 16b and groove 17a, 17b form connecting path between combustion chamber and inner surface of cylinder and combustion chamber. The fuel, jetted at the final stage of compression stroke, passes through connecting path and combusts by itself in combustion chamber. Moreover, set point of the period of compression stroke and expansion stroke and compression ratio are made possible to change by changing the phase of two pistons which swing the scavenging port and exhaust port, and also by changing the set point of aperture size of scavenging and exhaust port and that of swing timing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an opposed-piston two-cycle uniflow engine.

[0002]

2. Description of the Related Art An opposed-piston two-stroke uniflow engine in which an intake port and an exhaust port opened in a cylinder are opened and closed by reciprocating movement of an intake port opening and closing piston and an exhaust port opening and closing piston disposed in the cylinder, respectively. As a conventional example, a Junkers type two-cycle diesel engine is introduced on pages 171 to 174 of "History of Internal Combustion Engines" published by Sanei Shobo Co., Ltd. on December 25, 1969 by Sanei Shobo.

[0003] In the combustion of a diesel engine, which is a compression ignition engine, scavenging air (air) flowing into a cylinder during an intake stroke induces an increase in the temperature of the scavenging air due to compression in the next compression stroke. By injecting the fuel, the fuel starts to self-burn while mixing with the hot scavenging air.

[0004]

However, when starting the engine in a cold state, the scavenging air flowing into the cylinder during the suction stroke is low in temperature, and the temperature rise of the scavenging air caused by the compression stroke causes the cooling of the cooled cylinder and the combustion chamber. Heat is deprived by the piston, cylinder, and cylinder head to be formed, and the ultimate temperature decreases.

[0005] If the temperature is such that the fuel cannot self-combust, the engine cannot be started. Therefore, a glow plug or the like that promotes fuel vaporization and ignition is required. It is difficult. Therefore, by setting the compression ratio higher than necessary, the ultimate temperature of scavenging gas is increased, and the engine is easily started.

However, after the start, the temperature of the cylinder and the combustion chamber rises due to the heating by the combustion of the fuel, and accordingly, the scavenging air in the cylinder by the compression stroke raises the ultimate temperature. Further, the ultimate pressure increases as the ultimate temperature rises, and further, as the ultimate temperature rises and the ultimate pressure increases, the combustion temperature rises and the combustion pressure respectively increases. However, an increase in combustion temperature promotes the synthesis of polluting nitrogen oxides (NOx), and an increase in combustion pressure and combustion temperature increases the risk of engine breakage.
As a countermeasure, there was a problem that required robust design and production of the institution.

As a countermeasure, increasing the compression ratio is effective for improving the startability, but decreasing the compression ratio with the heating of the engine after the start is effective for solving the above problems. Therefore, a mechanism capable of arbitrarily changing the compression ratio is desired. In a two-stroke uniflow engine with opposed pistons disclosed in Japanese Patent Application Laid-Open No. 55-146231, means for synchronizing the phases of two reciprocating pistons arranged opposite to each other in a cylinder. A method has been disclosed in which two crankshafts that rotate in synchronization with the piston are linked to each other by a chain to achieve this.

[0008] According to this structure, the phase of the two crankshafts can be changed by changing the length of the linear motion part in two directions of the chain that links the two sprockets fixed to the rotating crankshaft. The compression ratio can be varied by the difference in the top dead center timing between the two pistons reciprocating in the cylinder in opposition.

However, as in the above published technology,
When a chain or a belt is used as a means for synchronizing the phases of the two crankshafts, the tension of the chain or the belt greatly changes in the vertical direction due to a difference in output and load generated between the two crankshafts.

Accordingly, in a mechanism for synchronizing the phase between two crankshafts by tensioning a chain or a belt, it is difficult to synchronize the phase between the two crankshafts due to a change in slack required for tensioning the chain or the belt. Due to differences in chain and belt elongation caused by differences in output and load between the two crankshafts, which change due to the phase difference,
Achieving goals is difficult.

FIG. 1 shows the structure of a piston of a Junkers type two-stroke diesel engine and the shape of a combustion chamber at the end of a compression stroke, as a conventional technique. As shown in this figure, since a part of the combustion chamber is formed by the cylinder, the oil necessary for lubricating the reciprocating motion of the piston attached to the cylinder evaporates due to the rise in the temperature of the cylinder due to the heating of the exposed part of the cylinder. As a result, there is a problem that wear of the cylinder and the piston ring is promoted.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and reduces the exposed portion of a cylinder by changing the shape of a combustion chamber, and furthermore, the opening / closing timing and opening area of an intake port and an exhaust port opened in the cylinder. By changing and controlling the phases of the two crankshafts variably, the compression ratio and the compression and expansion strokes can be arbitrarily changed according to the operating conditions, thereby improving performance and reducing fuel consumption and pollution.

[0013]

According to the first aspect of the present invention, a scavenging port opened in the cylinder and an exhaust port are opened and closed in a cylinder for opening and closing the exhaust port. The cavities and grooves formed on the top surfaces of the intake port opening / closing piston and the exhaust port opening / closing piston are used to close the combustion chamber and the cylinder inner peripheral wall and the combustion chamber at the timing when the two pistons approach from the end of the compression stroke to the beginning of the expansion stroke. A communication path is formed to communicate with.

According to the second aspect of the present invention,
A bevel gear moves between two crankshafts that rotate in conjunction with the reciprocating motion of a scavenging port opening / closing piston and an exhaust port opening / closing piston that are opposed to each other and open / close a scavenging port and an exhaust port opened in the cylinder. In the mechanism for synchronizing by rotating the rotating shaft and the gears, means for arbitrarily changing the phase between the two crank shafts is provided between the two linked crank shafts.

According to the third aspect of the present invention, the opening and closing of the intake port and the exhaust port opened in the cylinder are controlled by reciprocating the intake port opening and closing piston and the exhaust port opening and closing piston respectively disposed in the cylinder. In a two-stroke, opposed-piston type uniflow engine operated by movement, a sleeve forming a cylinder can slide to an arbitrary position.

Further, according to the fourth aspect of the present invention, the intake port and the exhaust port opened in the cylinder are opened and closed by reciprocating the intake port opening and closing piston and the exhaust port opening and closing piston respectively arranged in the cylinder. In an opposed-piston two-cycle uniflow engine operated by dynamic action, means for independently changing the opening area and opening timing of an intake port and an exhaust port opened in a cylinder are provided.

[0017]

[Function] As a feature of the opposed piston type two-cycle uniflow type engine, the opening and closing of the intake port and exhaust port opened in the cylinder are performed by the reciprocating movement of the dedicated intake port opening and closing piston and exhaust port opening and closing piston.
In comparison with a conventional two-stroke engine in which the intake port and the exhaust port are opened and closed by one piston, the opening area of the intake port and the exhaust port can be enlarged, and the intake port and the exhaust port that are opened in the cylinder can be opened. Because of the distance, the proportion of burned gas remaining in the cylinder can be reduced, and the remaining burned gas lowers the combustion temperature and reduces NOx (nitrogen oxide) contained in the exhaust gas. .

Further, in the present invention, the scavenging gas pressurized by the scavenging pump flows into the cylinder during the suction stroke while generating swirl by the scavenging port opened in the cylinder as shown in FIG. The swirl starts flowing into the cavity formed on the piston top surface shown in FIG. 4 by the start of the compression stroke.

Therefore, at the timing when the two pistons approach each other from the end of the compression stroke to the beginning of the expansion stroke, the fuel injected by the fuel injection nozzle into the combustion chamber formed by the cavities shown in FIG. The fuel flows into the combustion chamber through a fuel injection passage communicating the fuel injection port formed by the groove and the combustion chamber. This fuel is vaporized by the swirl in the combustion chamber.
Since diffusion is promoted and self-combustion starts, particulate matter (PM) generated by incomplete combustion is reduced.

[0020]

Embodiments will be described below with reference to the accompanying drawings. FIG. 2 is a vertical sectional view showing an embodiment of the opposed-piston two-stroke engine according to the present invention. In the figure, a sleeve 9 slidable by a sleeve sliding device 12A is inserted into a main body 1 to form a cylinder, and the sleeve sliding device 12A is controlled by the operation of a motor 11A.

In the sleeve 9, a scavenging port opening / closing piston 3A and an exhaust port opening / closing piston 3B are disposed to face each other, and open and close the scavenging port 5A and the exhaust port 5B respectively opened in the cylinder.

The pistons 3A, 3B are connected to the crankshafts 2A, 2B via connecting rods 4A, 4B to rotate the crankshaft. Bevel gear 7 meshing with bevel gears 6A, 6B fixed to one end of the crankshafts 2A, 2B
A and 7B are axis 23 tuned by the phase changing device 12B
A and 23B synchronize the phases of the two crankshafts. Note that the phase changing device 12B moves the shaft 2 by moving the shift fork 27 by the operation of the motor 11B.
The phase of 3A and 23B can be arbitrarily changed.

In starting at low temperature, the operation of the motor 11A causes the sleeve sliding device 12A to slightly slide the sleeve 9 forming the cylinder from the direction of the crankshaft 2A to the direction of the crankshaft 2B. Thereby, the scavenging port 5
A increases the operating angle and opening area from opening to closing,
Conversely, at the exhaust port 5B, the operating angle from the opening to the closing and the opening area decrease.

Then, in order to advance the opening / closing timing of the scavenging port 5A and delay the opening / closing timing of the exhaust port 5B, the motor 11B is controlled by the phase variable device 12 indicated by 6.
B is slightly moved from the direction of the shaft 23B to the direction of the shaft 23A by the shift fork 27, so that the shafts 23A and 23B
The timing of the crankshaft 2A connected to the scavenging port opening / closing piston 3A is slightly advanced, and the timing of the crankshaft 2B connected to the exhaust port opening / closing piston 3B is slightly delayed.

According to the above configuration, the difference in phase difference near the top dead center where the pistons 6A and 6B reciprocating in the sleeve 9 constituting the cylinder come closest is small, and the compression ratio can be set higher. Become.

Further, the position of the scavenging port opening / closing piston 3A at the time when the exhaust port opening / closing piston 3B opens the exhaust port 5B at the end of the expansion stroke, and the position of the exhaust port opening / closing piston 3B at the start of the compression stroke.
Due to the difference from the position of the scavenging port opening / closing piston 3A when B is closed, the expansion stroke is reduced, and the thermal efficiency is reduced. However, since the actual compression ratio is improved by increasing the compression stroke, it is easy to start the engine at a low temperature.

In the operation according to this configuration, the pistons 3A and 3B reciprocate in the sleeve 9 constituting the cylinder.
After the end of the expansion stroke, first, the exhaust port opening / closing piston 3B opens the exhaust port 5B. As a result, the burned gas of the previous cycle is rapidly discharged out of the cylinder.

Thereafter, the scavenging gas which has been supercharged by the supercharging device 13 and cooled by the cooling device 14 by the scavenging port opening / closing piston 6B opening the scavenging port 2 is transferred to the scavenging passage 10A.
, And flows into the sleeve 9 while generating a swirl through the scavenging port 5A which is opened in the sleeve 9 and is spirally angled, and most of the burned gas remaining in the sleeve 9 due to the flow of the scavenging air Is the exhaust port 5
B discharges out of the cylinder.

After passing through the bottom dead center, slide in the direction of the top dead center.
In the three pistons, first, the scavenging port opening / closing piston 3A closes the scavenging port 5A, and then the exhaust port 5B is closed by the exhaust port opening / closing piston 3B, and the compression stroke is started.

Next, as the compression stroke progresses, the piston 3
When A and 3B approach, the scavenging air in the sleeve 9 flows into the cavities 16A and 16B formed in the piston top surface without reducing the swirl flow.

Further, when the pistons 3A and 3B approach, the cavities 16A and 16B and the grooves 17A and 17B formed on the piston top surface as shown in FIG. 5 cause the combustion chamber, the combustion chamber, the inner peripheral surface of the sleeve and the combustion chamber. Is formed.

The fuel injected from the fuel injection nozzle 8 from the end of the compression stroke immediately before the pistons 3A and 3B come closest to each other passes through the fuel injection port 15 opened in the sleeve 9 and the grooves 17A and 17A on the piston top surface. The fuel flows through the communication passage formed by the combustion chamber 17B and communicates with the combustion chamber, flows into the combustion chamber, and the swirl in the combustion chamber promotes vaporization and diffusion of the fuel, and the fuel starts self-combustion.

After starting, in the conventional engine, the ultimate temperature and the ultimate pressure of scavenging in the cylinder by the compression stroke increase according to the heating of the engine by the combustion of fuel, and the combustion temperature and the combustion pressure increase accordingly.

However, an increase in the combustion temperature promotes the synthesis of nitrogen oxides (NOx), and the engine must be rugged because of the risk of engine damage due to an increase in the combustion temperature and combustion pressure. .

Therefore, the present invention provides a low load operation
As the engine is heated, the motor 11B is operated to move the phase variable device 12B connected to the shift fork 27 to the shaft 2
It is moved from the 3A direction to the shaft 23B direction.

The opening / closing timing of the scavenging port 5A is arbitrarily advanced according to the moving distance of the phase variable device 12B.
The opening and closing timing of the exhaust port 5B can be set to be delayed, but it is difficult to accurately operate the engine due to the approach of the opening timing of the intake and exhaust ports for opening and closing the two pistons. 11
A, when the sleeve 9 is slid from the direction of the crankshaft 2B to the direction of the crankshaft 2A, the exhaust port 5B
Thus, the above-described correction is facilitated by increasing the opening area and the opening timing, and conversely, by reducing the opening area and the opening timing of the scavenging port 5A.

In accordance with the above setting change, the position of the scavenging port opening / closing piston 3A at the time when the exhaust port opening / closing piston 3B opens the exhaust port 5B at the end of the expansion stroke shifts to the bottom dead center side, thereby causing expansion. The journey increases.

Conversely, the position of the scavenging port opening / closing piston 3A at the time when the exhaust port opening / closing piston 3B closes the exhaust port 5B at the start of the compression stroke shifts to the top dead center side. Decrease.

As a result, the engine displacement and the compression ratio are reduced due to the reduction of the compression stroke, the above-mentioned problems caused by the excessively high compression are solved, and furthermore, it is possible to flow into the cylinder by reducing the opening area of the scavenging port. A decrease in combustion temperature due to an increase in the proportion of burned gas remaining in the cylinder accompanying a decrease in the scavenging amount is effective in reducing nitrogen oxides (NOx). In addition, an increase in the expansion stroke improves the thermal efficiency, thereby providing an advantage that is effective in reducing carbon dioxide (CO ₂ ) and fuel consumption.

With the above setting, it is difficult to cope with a situation where a certain amount of output is required. Therefore, in the present invention, the operation of the motor 11B causes the phase variable device 12B connected to the shift fork 27 to move from the direction of the shaft 23B to the direction of the shaft 23A. In proportion to the movement distance, the timing at which the exhaust port opening / closing piston 3B opens / closes the exhaust port 5B advances, and conversely, the timing at which the scavenging port opening / closing piston 3A opens / closes the scavenging port is delayed.

Therefore, with the operation of the motor 11A,
The sleeve sliding device 12A connects the sleeve 9 to the crankshaft 2
It is slid from the direction B to the direction of the crankshaft 2A. As a result, in the scavenging port 5A, the opening area and the opening timing of the exhaust port 5B are increased, and the opening area of the exhaust port 5B and the opening timing are reduced. Is advanced, and the compression stroke is expanded.

In accordance with the above setting change, the position of the scavenging port opening / closing piston 3A at the time when the exhaust port opening / closing piston 3B opens the exhaust port 5B at the end of the expansion stroke shifts to the top dead center side, thereby increasing the expansion stroke. Decreases.

However, since the position of the scavenging port opening / closing piston 3A at the time when the exhaust port opening / closing piston 3B closes the exhaust port 5B at the start of the compression stroke shifts to the bottom dead center side, the compression stroke expands. , The actual displacement increases.

Further, the amount of scavenging gas flowing into the cylinder is increased by increasing the opening area of the scavenging port, and the burned gas remaining in the cylinder is reduced by increasing the scavenging amount. As a result, although the thermal efficiency decreases with a decrease in the expansion stroke, it is easy to cope with a situation where a certain output or more is required.

Further, in a situation where more output is required, the two crankshafts 2A, 2A
When the phase of B is further changed, the timing at which the scavenging port opening / closing piston 3A closes the scavenging port 5A and the timing at which the exhaust port opening / closing piston 3B closes the exhaust port 5B are reversed, so that even after the exhaust port opening. The scavenging port continues to be opened, during which the scavenging air supercharged by the supercharging device 13 and cooled by the cooling device 14 continues to flow into the cylinder, so that supercharging is possible. Also, the compression ratio is reduced due to the mismatch of the top dead center timings of the two pistons that reciprocate oppositely.

In such a configuration, the thermal efficiency decreases due to a decrease in the expansion stroke. However, the expansion of the compression stroke and the increase in the amount of exhaust due to supercharging make it easier to improve the output.
Since fuel vaporization and mixing with scavenging are promoted, particulate matter (PM) generated by incomplete combustion can be reduced. Also, the reduction in particulate matter (PM) has made it possible to reduce fuel consumption.

However, the improvement in combustion efficiency due to the above-described improvement in combustion raises the problem that the combustion temperature rises, thereby increasing the amount of generated nitrogen oxides (NOx).
However, according to the operation of the engine according to the above setting, the combustion temperature can be reduced due to the reduction of the compression ratio due to the mismatch of the top dead center timings of the two pistons reciprocating in the cylinder, and the piston remains in the cylinder. A reduction in the emission temperature of nitrogen oxides (NOx) due to a decrease in the combustion temperature due to the burned gas has also become possible.

Next, in the embodiment shown in FIG. 7, the scavenging port opening / closing piston 3A for opening and closing the scavenging port 5A and the exhaust port 5B opened in the cylinder, and the reciprocating motion of the exhaust port opening / closing piston 3B are interlocked. As means for synchronizing the phases of the rotating crankshafts 2A and 2B, a spur gear 1
The spur gear 19A, which rotates in conjunction with a spline threaded on the shaft end of the crankshaft 2A in a structure in which the gears 9A, 19B, and 19C mesh with each other, is rotated by a motor 11
C activates the phase varying device 12C to enable it to move in the longitudinal direction of the crankshaft.

Further, a scavenging port 5 opened in the cylinder opened and closed by a scavenging port opening / closing piston 3A and an exhaust port opening / closing piston 3B opposed to each other in the cylinder.
An independent scavenging valve 20A and an exhaust valve 20B are provided for A and the exhaust port 5B, and the opening area and the opening / closing timing can be arbitrarily changed.

According to this structure, the motor 11C operates the phase variable device 12C to move the spur gear 19A in the longitudinal direction of the crankshaft, so that the spline gear threaded to the crankshaft 2A and the spur gear 19A is screwed. The angle of the crankshaft 2A can be changed in the direction of rotation, so that it can arbitrarily change the rotation timing of the phase synchronized between the rotating crankshaft 2A and the crankshaft 2B.

Further, the reciprocation of the scavenging port opening / closing piston 3A and the exhaust port opening / closing piston 3B in the cylinder depends on the operation positions of the scavenging valve 20A and the exhaust valve 20B provided in the scavenging port 5A and the exhaust port 5B opened in the cylinder. The opening area and opening / closing timing of the scavenging port 5A and the exhaust port 5B opened in the cylinder which opens and closes by movement can be freely changed. As a result, the same effect as that of the embodiment shown in FIG. It has become possible.

The mechanism for generating the phase difference between the two crankshafts can be set for either of the two crankshafts.

In the embodiment shown in FIG. 8, the meshing of the spur gears 19A, 19B, and 19C for synchronizing the phases of the crankshafts 2A and 2B shown in the above embodiment is performed with the helical gears 21A, 21B, and 21C. And the helical gear 21A, which rotates in conjunction with the crankshaft 2A, can be slid in the front-rear direction of the crankshaft 2A.

According to this structure, the shift fork 27 slides the gear 21A in the front-rear direction of the crankshaft 2A by the operation of the motor 11D. The sliding angle changes the rotation angle of the gear 21C meshed with the gear 21A and further moves the angle of the gear 21B, so that the phases of the crankshafts 2A and 2B tuned by the meshing of the gears can be changed. .

The above mechanism can be set on either of the two crankshafts. If the intermediate helical gear for interlocking the two crankshafts is set to an even number, the above mechanism becomes all helical gears. It is possible with either one of the settings.

Further, according to the shapes of the cavity and the groove formed on the top surface of the piston of the embodiment shown in FIG. 10, at the timing of the start of the expansion stroke from the end of the compression stroke when two opposing pistons come closest to each other, the annular shape is obtained. It is possible to form a communication path that communicates the combustion chamber with the glow plug 22 and the fuel injection port 28 with the combustion chamber.

By the way, in the piston of the embodiment shown in FIG. 5, a layer of metal and ceramic is further adhered by vapor deposition and plating on the piston top surface including the cavity and the groove, and the piston and the cavity are generated on the piston top surface including the groove. The piston has a heat insulating structure from heating by combustion.

FIGS. 7 to 10 show engines operating on alcohol-based and liquefied petroleum-gas based fuels. Conventional alcohol-based fuel engines have a problem in that starting at low temperatures is difficult because alcohol-based fuels do not contain low-boiling components, and harmful formaldehyde is generated by incomplete combustion. Therefore, there is a problem in that the output is reduced due to the difficulty in vaporizing the fuel due to the exhaust gas, and a decrease in the displacement due to the scavenging air (intake) whose volume has increased due to the vaporization outside the cylinder flowing into the cylinder.

However, according to the engine of the present invention, the two pistons inject fuel into the cylinder from the fuel injection nozzle (not shown) after the start of the compression stroke after scavenging and closing the exhaust port during cold start. The problem of output drop does not occur.

The fuel is agitated by the swirl in the cylinder, and ignition and combustion are started by the glow plug 22 and a spark plug (not shown). Once the combustion starts, this phenomenon is peculiar to a two-cycle engine. The burned gas remaining in the cylinder facilitates continuation of combustion, and significantly reduces the amount of harmful formaldehyde generated by incomplete combustion, which is a problem with alcohol fuels.

Further, since the compression ratio can be easily changed, different types of fuel can be used in one engine.

The scavenging port opening / closing piston reciprocating in the cylinder and the scavenging port opening / closing piston allow different settings of the piston stroke and the bore diameter of the cylinder.

[0063]

As described above, according to the structure of the opposed-piston two-stroke uniflow engine of the present invention, the phase of the two pistons for opening and closing the scavenging port and the exhaust port opened in the cylinder is further changed. By freely changing the setting of the opening area and the opening / closing timing of the sweep / exhaust port, the length of the compression stroke and the expansion stroke and the setting of the compression ratio can be changed.

As a result, improvement of the maximum output by increasing or decreasing the optimal compression ratio and the displacement by the change of the required output, reduction of the carbon dioxide by reducing the fuel consumption, and the problem of the two-stroke engine have been considered as problems. The burned gas remaining in the cylinder is effective as a measure to reduce nitrogen oxides (NOx), and the supercharged scavenging gas flows into the cylinder while generating a strong vortex (swirl). It is easy and the emission of particulate matter (PM) can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a shape of a combustion chamber and a cylinder and a piston at the end of a compression stroke of a conventional Junkers type two-cycle diesel engine.

FIG. 2 is a longitudinal sectional view of an opposed-piston type two-cycle uniflow engine according to an embodiment of the present invention.

FIG. 3 is a sectional view of a scavenging port in the embodiment of FIG. 2;

FIG. 4 is a perspective view of a scavenging port opening / closing piston in the embodiment of FIG. 2;

5 is a cross-sectional view of a cylinder and two pistons at the end of a compression stroke in the embodiment of FIG. 2;

FIG. 6 is a perspective sectional view of the variable phase device in the embodiment of FIG. 2;

FIG. 7 is a longitudinal sectional view showing another embodiment of the present invention.

FIG. 8 is a longitudinal sectional view showing still another embodiment of the present invention.

FIG. 9 is a perspective view of an exhaust valve in the embodiment of FIG.

FIG. 10 is a perspective view of an exhaust port opening / closing piston in the embodiment of FIG. 8;

FIG. 11 is a sectional view showing another embodiment of the variable phase device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2A, B Crankshaft 3A, B Piston 4A, B Connecting rod 5A Scavenging port 5B Exhaust port 8 Fuel injection nozzle 9 Sleeve 10B Exhaust passage 11A, B Motor 12A Sleeve sliding device 12B Variable phase device 13 Supercharging device 14 Cooling device 15 Output shaft 16A, B Cavity 17A, B groove 20B Exhaust valve 22 Glow plug 23A, B, C shaft 24 Piston pin 25 Piston ring 26 Flywheel 27 Shift fork 29 Ceramic layer 31 Sector 32 Burning plate

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) F02F 1/22 F02F 1/22 A F term (reference) 3G023 AA02 AA04 AA05 AA08 AB05 AC04 AD01 AD06 AF01 AF02 AF03 3G024 AA09 AA25 DA02 DA14 DA15 DA17 DA25 FA00 3G092 AA02 AA03 AA06 AA10 AA11 AA12 AA18 AB03 DA03 DD08 FA17 FA18 GA01

Claims (4)

[Claims] An opposed-piston type two-cycle uniflow type in which an intake port and an exhaust port opened in a cylinder are opened and closed by reciprocating movement of an intake port opening and closing piston and an exhaust port opening and closing piston disposed opposite to each other in a cylinder. At the timing when the two pistons approach each other from the end of the compression stroke to the beginning of the expansion stroke in the engine, a communication passage that connects the combustion chamber and the inner peripheral wall of the cylinder to the combustion chamber is formed by the cavity and the groove formed on the piston top surface. An opposed-piston two-stroke uni-flow engine characterized by having the following structure. 2. A means for synchronizing the phases between two crankshafts rotating in conjunction with the reciprocation of a scavenging port opening / closing piston and an exhaust port opening / closing piston for opening and closing an intake port and an exhaust port opened in a cylinder. As
An opposed-piston two-stroke uniflow engine in which the phase of two tuned crankshafts can be arbitrarily changed in an opposed-piston two-stroke uniflow engine in which a rotating shaft and a gear mesh with each other. 3. An opposed-piston two-cycle uniflow type in which an intake port and an exhaust port opened in the cylinder are opened and closed by reciprocating movement of an intake port opening / closing piston and an exhaust port opening / closing piston opposed to each other in a cylinder. An opposed-piston type two-stroke uniflow engine, wherein a sleeve forming a cylinder is slidable at an arbitrary position. 4. An opposed-piston two-stroke uniflow engine that opens and closes an intake port and an exhaust port opened in a cylinder by reciprocating movement of an intake port opening / closing piston and an exhaust port opening / closing piston opposed to each other in a cylinder. , A means for independently changing the opening area and the opening / closing timing of the intake port and exhaust port openings opened in the cylinder is provided.